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Sample records for csi detector array

  1. Charged-particle detection efficiencies of close-packed CsI arrays

    NASA Astrophysics Data System (ADS)

    Morfouace, P.; Lynch, W. G.; Tsang, M. B.

    2017-03-01

    Detector efficiency determination is essential to correct the measured yields and extract reliable cross sections of particles emitted in nuclear reactions. We investigate the efficiencies for measuring the full energies of light charged particle in arrays of CsI crystals employed in particle detection arrays such as HiRA, LASSA and MUST2. We perform these simulations with a GEANT4 Monte Carlo transport code implemented in the NPTool framework. Both Coulomb multiple scattering and nuclear reactions within the crystal can significantly reduce the efficiency of detecting the full energy of high energy particles. The calculated efficiencies decrease exponentially as a function of the range of the particle and are quite similar for both the hydrogen (p , d , t) and helium (3He, α) isotopes. The use of a close-packed array introduces significant position dependent efficiency losses at the interior boundaries between crystals that need to be considered in the design of an array and in the efficiency corrections of measured energy spectra.

  2. Solid state neutron detector array

    SciTech Connect

    Seidel, J.G.; Ruddy, F.H.; Brandt, C.D.; Dulloo, A.R.; Lott, R.G.; Sirianni, E.; Wilson, R.O.

    1999-08-17

    A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors. 7 figs.

  3. Advanced UV Detectors and Detector Arrays

    NASA Technical Reports Server (NTRS)

    Pankove, Jacques I.; Torvik, John

    1998-01-01

    Gallium Nitride (GaN) with its wide energy bandgap of 3.4 eV holds excellent promise for solar blind UV detectors. We have successfully designed, fabricated and tested GaN p-i-n detectors and detector arrays. The detectors have a peak responsivity of 0.14A/W at 363 nm (3.42 eV) at room temperature. This corresponds to an internal quantum efficiency of 56%. The responsivity decreases by several orders of magnitude to 0.008 A/W at 400 nm (3.10 eV) giving the excellent visible rejection ratio needed for solar-blind applications.

  4. Detector Arrays For Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Mccreight, C. R.; Mckelvey, M. E.; Goebel, J. H.; Anderson, G. M.; Lee, J. H.

    1988-01-01

    Paper describes status of program for developing integrated infrared detectors for astronomy. Program covers variety of detectors, including extrinsic silicon, extrinsic germanium, and indium antimonide devices with hybrid silicon multiplexers. Paper notes for arrays to reach background noise limit in cryogenic telescope, continued reductions in readout noise and dark current needed.

  5. A CsI low-temperature detector for dark matter search

    NASA Astrophysics Data System (ADS)

    Angloher, G.; Dafinei, I.; Gektin, A.; Gironi, L.; Gotti, C.; Gütlein, A.; Hauff, D.; Maino, M.; Nagorny, S. S.; Nisi, S.; Pagnanini, L.; Pattavina, L.; Pessina, G.; Petricca, F.; Pirro, S.; Pröbst, F.; Reindl, F.; Schäffner, K.; Schieck, J.; Seidel, W.; Vasyukov, S.

    2016-11-01

    Cryogenic detectors have a long history of success in the field of rare event searches. In particular scintillating calorimeters are very suitable detectors for this task since two signals are induced by a particle interaction in a scintillating crystal. The thermal signal provides a precise measurement of the deposited energy while the simultaneously measured scintillation light signal yields particle discrimination as the amount of produced scintillation light depends on the nature of the interacting particle. We investigate the calorimetric properties and background rejection capabilities of two large CsI (undoped) crystals (∼122 g each) operated as scintillating calorimeters at milli-Kelvin temperatures. Furthermore, we discuss the feasibility of this detection approach towards a future background-free dark matter experiment based on alkali halide crystals, with active particle discrimination via the two-channel detection.

  6. Massively Parallel MRI Detector Arrays

    PubMed Central

    Keil, Boris; Wald, Lawrence L

    2013-01-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called “ultimate” SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays. PMID:23453758

  7. Stressed detector arrays for airborne astronomy

    NASA Technical Reports Server (NTRS)

    Stacey, G. J.; Beeman, J. W.; Haller, E. E.; Geis, N.; Poglitsch, A.; Rumitz, M.

    1989-01-01

    The development of stressed Ge:Ga detector arrays for far-infrared astronomy from the Kuiper Airborne Observatory (KAO) is discussed. Researchers successfully constructed and used a three channel detector array on five flights from the KAO, and have conducted laboratory tests of a two-dimensional, 25 elements (5x5) detector array. Each element of the three element array performs as well as the researchers' best single channel detector, as do the tested elements of the 25 channel system. Some of the exciting new science possible with far-infrared detector arrays is also discussed.

  8. Quantum efficiencies of imaging detectors with alkali halide photocathodes. I - Microchannel plates with separate and integral CsI photocathodes

    NASA Technical Reports Server (NTRS)

    Carruthers, George R.

    1987-01-01

    Measurements and comparisons have been made of the quantum efficiencies of microchannel plate (MCP) detectors in the far-UV (below 2000-A) wavelength range using CsI photocathodes (a) deposited on the front surfaces of microchannel plates and (b) deposited on solid substrates as opaque photocathodes with the resulting photoelectrons input to microchannel plates. The efficiences were measured in both pulse-counting and photodiode modes of operation. Typical efficiencies are about 15 percent at 1216 A for a CsI-coated MCP compared with 65 percent for an opaque CsI photocathode MCP detector. Special processing has yielded an efficiency as high as 20 percent for a CsI-coated MCP. This may possibly be further improved by optimization of the tilt angle of the MCP channels relative to the front face of the MCP and incident radiation. However, at present there still remains a factor of at least 3 quantum efficiency advantage in the separate opaque CsI photocathode configuration.

  9. Arrays of Bolometric Detectors for Submillimeter Astronomy

    NASA Technical Reports Server (NTRS)

    Silverberg, R. F.; Moseley, S. H.; Freund, M.; Allen, C.; Harper, A.; Loewenstein, R.; Dowell, C. D.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    Large format two dimensional arrays of bolometric detectors are required for many millimeter and submillimeter applications. We describe the development and testing of such arrays and the plans for using them in both a ground-based and airborne instrument.

  10. Quantum efficiency of opaque CsI photocathodes with channel electron multiplier arrays in the extreme and far ultraviolet

    NASA Technical Reports Server (NTRS)

    Martin, C.; Bowyer, S.

    1982-01-01

    The arrays are overcoated with a CsI photocathode in the VUV. The measurements are part of the development program for the Extreme Ultraviolet Explorer. Monochromatic light from a hollow cathode discharge source passing through a McPherson grazing incidence monochromator is used to illuminate the CsI photocathode. The beam diameter is kept small (approximately 2 mm) to confine it within the individual thickness strips. A bias grid is used to produce a 50-V/mm electric field to guarantee collection of all photoelectrons emitted by the CEMA (channel electron multiplier array) webbing. The CEMAs are operated with a gain of 2-3 x 10 to the 6th and are moderately saturated. A channeltron secondary transfer standard is used to determine the absolute QE in the EUV, whereas an NBS calibrated windowed photodiode is used to measure the FUV absolute QE. It is noted that the CsI gives a factor of 3 increase in the QE in the EUV and a factor of 50-5000 in the FUV.

  11. Si:As BIB detector arrays

    NASA Technical Reports Server (NTRS)

    Bharat, R.; Petroff, M. D.; Speer, J. J.; Stapelbroek, M. G.

    1986-01-01

    Highlights of the results obtained on arsenic-doped silicon blocked impurity band (BIB) detectors and arrays since the invention of the BIB concept a few years ago are presented. After a brief introduction and a description of the BIB concept, data will be given on single detector performance. Then different arrays that were fabricated will be described and test data presented.

  12. Junction-side illuminated silicon detector arrays

    DOEpatents

    Iwanczyk, Jan S.; Patt, Bradley E.; Tull, Carolyn

    2004-03-30

    A junction-side illuminated detector array of pixelated detectors is constructed on a silicon wafer. A junction contact on the front-side may cover the whole detector array, and may be used as an entrance window for light, x-ray, gamma ray and/or other particles. The back-side has an array of individual ohmic contact pixels. Each of the ohmic contact pixels on the back-side may be surrounded by a grid or a ring of junction separation implants. Effective pixel size may be changed by separately biasing different sections of the grid. A scintillator may be coupled directly to the entrance window while readout electronics may be coupled directly to the ohmic contact pixels. The detector array may be used as a radiation hardened detector for high-energy physics research or as avalanche imaging arrays.

  13. Infrared array detectors. [for astronomical observation

    NASA Technical Reports Server (NTRS)

    Arens, J. F.

    1982-01-01

    Arrays of detectors sensitive to infrared radiation will enable astronomical observations to be made with shorter observing times than with discrete detectors and with good relative spatial accuracy. Systems using such arrays are being developed for astronomy in several regions of the electromagnetic spectrum. An example of an infrared system is given here consisting of a 32x32 element bismuth doped silicon charge injection device array that has been used in an astronomical camera.

  14. Imaging responses of on-site CsI and Gd2O2S flat-panel detectors: Dependence on the tube voltage

    NASA Astrophysics Data System (ADS)

    Jeon, Hosang; Chung, Myung Jin; Youn, Seungman; Nam, Jiho; Lee, Jayoung; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Ho Kyung

    2015-07-01

    One of the emerging issues in radiography is low-dose imaging to minimize patient's exposure. The scintillating materials employed in most indirect flat-panel detectors show a drastic change of X-ray photon absorption efficiency around their K-edge energies that consequently affects image quality. Using various tube voltages, we investigated the imaging performance of most popular scintillators: cesium iodide (CsI) and gadolinium oxysulfide (Gd2O2S). The integrated detective quantum efficiencies (iDQE) of four detectors installed in the same hospital were evaluated according to the standardized procedure IEC 62220-1 at tube voltages of 40 - 120 kVp. The iDQE values of the Gd2O2S detectors were normalized by those of CsI detectors to exclude the effects of image postprocessing. The contrast-to-noise ratios (CNR) were also evaluated by using an anthropomorphic chest phantom. The iDQE of the CsI detector outperformed that of the Gd2O2S detector over all tube voltages. Moreover, we noted that the iDQE of the Gd2O2S detectors quickly rolled off with decreasing tube voltage under 70 kVp. The CNRs of the two scintillators were similar at 120 kVp. At 60 kVp, however, the CNR of Gd2O2S was about half that of CsI. Compared to the Gd2O2S detectors, variations in the DQE performance of the CsI detectors were relatively immune to variations in the applied tube voltages. Therefore, we claim that Gd2O2S detectors are inappropriate for use in low-tube-voltage imaging (e.g., extremities and pediatrics) with low patient exposure.

  15. Thermopile Detector Arrays for Space Science Applications

    NASA Technical Reports Server (NTRS)

    Foote, M. C.; Kenyon, M.; Krueger, T. R.; McCann, T. A.; Chacon, R.; Jones, E. W.; Dickie, M. R.; Schofield, J. T.; McCleese, D. J.; Gaalema, S.

    2004-01-01

    Thermopile detectors are widely used in uncooled applications where small numbers of detectors are required, particularly in low-cost commercial applications or applications requiring accurate radiometry. Arrays of thermopile detectors, however, have not been developed to the extent of uncooled bolometer and pyroelectric/ferroelectric arrays. Efforts at JPL seek to remedy this deficiency by developing high performance thin-film thermopile detectors in both linear and two-dimensional formats. The linear thermopile arrays are produced by bulk micromachining and wire bonded to separate CMOS readout electronic chips. Such arrays are currently being fabricated for the Mars Climate Sounder instrument, scheduled for launch in 2005. Progress is also described towards realizing a two-dimensional thermopile array built over CMOS readout circuitry in the substrate.

  16. High-resolution ionization detector and array of such detectors

    DOEpatents

    McGregor, Douglas S.; Rojeski, Ronald A.

    2001-01-16

    A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.

  17. Low background IR detector and detector array evaluations

    NASA Technical Reports Server (NTRS)

    Goebel, J. H.; Jared, D. A.; Lee, J. H.; Mccreight, C. R.; Mckelvey, M. E.; Stafford, P. S.

    1983-01-01

    A technology program has been underway at Ames since 1978 to develop and evaluate detectors and integrated detector arrays for low-background astronomical applications. The approach is to evaluate existing (less than 24 micron) array technology under low-background conditions, with the aim of adapting and optimizing existing devices. For longer wavelengths, where the technology is much less mature, development is sponsored and devices are evaluated, in both discrete and array formats, for eventual applications. The status of this program has been reported previously. We rely on industrial and university sources for the detectors. Typically, after a brief functionality check in the supplier's laboratory, we work with the device at Ames to characterize its low-background performance. In the case of promising arrays or detectors, we conduct ground-based telescope testing to face the problems associated with real applications. A list of devices tested at Ames is given. In the array category, accumulation-mode charge-injection-devices (AMCIDs) appear repeatedly; this reflects our recent experience with the 2 x 64 and 16 x 16 arrays. Results from the 1 x 16 CID and InSb CCD have been reported. The status of our tests of the discrete Ge:x detectors from Lawrence Berkeley Laboratory are described below. Tests of a 1 x 2 switched sample photoconductor array are just beginning. A 32-channel CMOS multiplexer has been tested at 10 K. Low-temperature silicon MOSFETs and germanium JFETs have also been tested, primarily at Ball Aerospace. This paper describes results to date on three elements of this program: AMCID array, discrete Ge:Ga detectors, and Ge JFET preamplifiers.

  18. Monolithic short wave infrared (SWIR) detector array

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

  19. Modeling Charge Collection in Detector Arrays

    NASA Technical Reports Server (NTRS)

    Hardage, Donna (Technical Monitor); Pickel, J. C.

    2003-01-01

    A detector array charge collection model has been developed for use as an engineering tool to aid in the design of optical sensor missions for operation in the space radiation environment. This model is an enhancement of the prototype array charge collection model that was developed for the Next Generation Space Telescope (NGST) program. The primary enhancements were accounting for drift-assisted diffusion by Monte Carlo modeling techniques and implementing the modeling approaches in a windows-based code. The modeling is concerned with integrated charge collection within discrete pixels in the focal plane array (FPA), with high fidelity spatial resolution. It is applicable to all detector geometries including monolithc charge coupled devices (CCDs), Active Pixel Sensors (APS) and hybrid FPA geometries based on a detector array bump-bonded to a readout integrated circuit (ROIC).

  20. Neutron detector characterization for SCINTIA array

    SciTech Connect

    Matei, C.; Hambsch, F. J.; Oberstedt, S.

    2011-07-01

    SCINTIA is a new detector array of organic scintillators under development at the Inst. for Reference Materials and Measurements (IRMM). The present design of SCINTIA includes NE213, p-terphenyl and Li glass neutron detectors positioned in a spherical configuration around the target. The properties of a novel p-terphenyl neutron detector to be used with SCINTIA have been investigated using photon sources and neutrons from a time tagged {sup 252}Cf(sf) source. The results show that the p-terphenyl crystal has better energy resolution, increased proton light output and neutron efficiency when compared to a similar size NE213 equivalent neutron detector. (authors)

  1. Array Detectors for Plasma Spectrochemistry.

    DTIC Science & Technology

    1988-02-04

    Applied Spectroscopy , (1987), 41, 1114. (2) R.B. Bilhorn, P.M. Epperson, J.V. Sweedler, M.B. Denton, Applied Spectroscopy , (1987), 41, 1125. 19. Abstract (continued) ,7different detector element based on the actual photon flux falling on each element during a specific measurement; binning, allowing the combination of charge stored in multiple elements while on the detector; and frame transfer, allowinq computer summation of multiple exposures of a single analysis.tA/,: -. • -’- ,, ,- - Readout modes such as random access

  2. Imaging Using Energy Discriminating Radiation Detector Array

    SciTech Connect

    Willson, Paul D.; Clajus, Martin; Tuemer, Tuemay O.; Visser, Gerard; Cajipe, Victoria

    2003-08-26

    Industrial X-ray radiography is often done using a broad band energy source and always a broad band energy detector. There exist several major advantages in the use of narrow band sources and or detectors, one of which is the separation of scattered radiation from primary radiation. ARDEC has developed a large detector array system in which every detector element acts like a multi-channel analyzer. A radiographic image is created from the number of photons detected in each detector element, rather than from the total energy absorbed in the elements. For high energies, 25 KeV to 4 MeV, used in radiography, energy discriminating detectors have been limited to less than 20,000 photons per second per detector element. This rate is much too slow for practical radiography. Our detector system processes over two million events per second per detector pixel, making radiographic imaging practical. This paper expounds on the advantages of the ARDEC radiographic imaging process.

  3. Study of a Li doped CsI scintillator crystal as a neutron detector

    NASA Astrophysics Data System (ADS)

    Madi Filho, T.; Pereira, M. C. C.; Berretta, J. R.; Cárdenas, J. P. N.

    2015-07-01

    The radiation monitoring system is an important requirement in the premises of a nuclear reactor. A variety of types of radiation (neutrons. gamma. beta and fission products) exist in a reactor. associated to the broad energy spectrum of these radiations. implying the need of detectors to be used in the reactor system and security. as well as radiation monitoring. As the neutron sources are associated to gamma radiation. it is necessary that the neutron detecting system may be capable to discriminate the gamma interference. In our work environment. there are two Nuclear Research Reactors and a neutron irradiator with two AmBe sources (592GBq of Am. each). These conditions warrant the development of new types of detectors. Due to the absence of charge in the neutron. it is necessary to use a converter material that generates radiations capable to produce signals in the detector. Materials with high cross section. like Li or B. are used for this purpose. The CsIcrystal doped with 6Li has been studied. The concentration of the lithium doping element (Li) studied was 10-3M. The detector test was done using an AmBe source (37GBq) and gamma sources. The crystal was coupled to a photomultiplier.

  4. A Study of the quality of CsI detectors and pulse-shape discrimination of scintillators for ?[U+0251]-particles, ?[U+0263]-particles, and neutrons

    NASA Astrophysics Data System (ADS)

    Salyer, Kaitlin; Rogachev, Grigory; Hooker, Joshua

    2016-09-01

    This project studied the capabilities of two different scintillators, Cesium Iodide (CsI) and p-Terphenyl. First, the resolution of a CsI detector was investigated by exposing only very small areas of its surface at a time to an alpha source. Second, the abilities of p-Terphenyl to detect alpha particles, gamma particles, and neutrons were analyzed through pulse shape discrimination. p-Terphenyl is of particular interest because it will be used in the Mitchell Institute Neutrino Experiment at Reactor (MINER) at Texas A&M University for measuring background data. The information learned from conducting these tests will be useful in understanding and expanding the limits of the experiments in which these detectors will ultimately be used.

  5. Adaptive Detector Arrays for Optical Communications Receivers

    NASA Technical Reports Server (NTRS)

    Vilnrotter, V.; Srinivasan, M.

    2000-01-01

    The structure of an optimal adaptive array receiver for ground-based optical communications is described and its performance investigated. Kolmogorov phase screen simulations are used to model the sample functions of the focal-plane signal distribution due to turbulence and to generate realistic spatial distributions of the received optical field. This novel array detector concept reduces interference from background radiation by effectively assigning higher confidence levels at each instant of time to those detector elements that contain significant signal energy and suppressing those that do not. A simpler suboptimum structure that replaces the continuous weighting function of the optimal receiver by a hard decision on the selection of the signal detector elements also is described and evaluated. Approximations and bounds to the error probability are derived and compared with the exact calculations and receiver simulation results. It is shown that, for photon-counting receivers observing Poisson-distributed signals, performance improvements of approximately 5 dB can be obtained over conventional single-detector photon-counting receivers, when operating in high background environments.

  6. SQUID Multiplexers for Cryogenic Detector Arrays

    NASA Technical Reports Server (NTRS)

    Irwin, Kent; Beall, James; Deiker, Steve; Doriese, Randy; Duncan, William; Hilton, Gene; Moseley, S. Harvey; Reintsema, Carl; Stahle, Caroline; Ullom, Joel; Vale, Leila

    2004-01-01

    SQUID multiplexers make it possible to build arrays of thousands of cryogenic detectors with a manageable number of readout channels. We are developing time-division SQUID multiplexers based on Nb trilayer SQUIDs to read arrays of superconducting transition-edge sensors. Our first-generation, 8-channel SQUID multiplexer was used in FIBRE, a one-dimensional TES array for submillimeter astronomy. Our second-generation 32-pixel multiplexer, based on an improved architecture, has been developed for instruments including Constellation-X, SCUBA-2, and solar x-ray astronomy missions. SCUBA-2, which is being developed for the James Clerk Maxwell Telescope, will have more than 10,000 pixels. We are now developing a third-generation architecture based on superconducting hot-electron switches. The use of SQUID multiplexers in instruments operating at above 2 K will also be discussed.

  7. Broadband optical absorption enhancement of hexagonal nanoconical frustum arrays texturing for c-Si film solarcells

    NASA Astrophysics Data System (ADS)

    Wangyang, Peihua; Wang, Qingkang; Hu, Kexiang; Wan, Xia; Huang, Kun

    2013-05-01

    In this paper, the optical properties of the silicon hexagonal nanoconical frustum (SiHNF) arrays are theoretically studied via simulation based on the Rigorous Coupled Wave Analysis (RCWA) in detail. The results show that the SiHNF bottom diameter (Dbot) should be equal to the array periodicity for efficient solar energy harvesting, and the optimized light absorption could be realized when the SiHNF height reaches 1000 nm with Dtop equal to100 nm. The optimal SiHNF arrays has the periodicity of 700 nm, the top diameter of 100 nm and the SiHNF height of 1000 nm, yielding an ultimate efficiency of 30.54%, which is more than two times of a 2.33 μm thick Si thin film solar cells. Comparing to nanopillar and square nanoconical frustum structures, the enhanced ultimate efficiency of SiHNF structure is less sensitive to the incident zenith angle and SiHNF top diameter. The possible physical mechanism behind the observation is also explored in thiswork.

  8. Spiral biasing adaptor for use in Si drift detectors and Si drift detector arrays

    DOEpatents

    Li, Zheng; Chen, Wei

    2016-07-05

    A drift detector array, preferably a silicon drift detector (SDD) array, that uses a low current biasing adaptor is disclosed. The biasing adaptor is customizable for any desired geometry of the drift detector single cell with minimum drift time of carriers. The biasing adaptor has spiral shaped ion-implants that generate the desired voltage profile. The biasing adaptor can be processed on the same wafer as the drift detector array and only one biasing adaptor chip/side is needed for one drift detector array to generate the voltage profiles on the front side and back side of the detector array.

  9. Interference effects in reticon photodiode array detectors.

    PubMed

    Mount, G H; Sanders, R W; Brault, J W

    1992-03-01

    A detector system incorporating the Reticon RL1024S photodiode array has been constructed at the National Oceanic and Atmospheric Administration Aeronomy Laboratory as part of a double spectrograph to be used to study the Earth's atmosphere from ground-based and aircraft-based platforms. To determine accurately the abundances of atmospheric trace gases, this new system must be able to measure spectral absorptions as small as 0.02%. The detector, manufactured by EG&G Reticon, exhibits superior signal-to-noise characteristics at the light levels characteristic of scattered skylights, but interference in the passivating layer (a thin layer of SiO(2) that is deposited during the manufacture to protect the silicon active area from water vapor) causes major problems in achieving the required precision. The mechanism of the problems and the solution we have implemented are described in detail.

  10. Microphone array based novel infant deafness detector.

    PubMed

    Agnihotri, Chinmayee; Thiyagarajan, S; Kalyansundar, Archana

    2010-01-01

    This work focuses on an infant deafness detector unit, using the concept of microphone array. This instrument is based on the principle of evoked acoustic emissions (OAEs). The key feature of the microphone array is its ability to increase signal-to-noise ratio (SNR) and reproducibility of the OAE responses. These further significantly contribute to improve the sensitivity and specificity of the overall system. Low level sound pressure values are recorded by the sensitive microphones in microphone array unit and processed using TI's DSP6416. The sound stimulus transmitted to human ear is generated and controlled by the 6416 DSP (Digital signal processor). Hardware circuit details and the algorithm used in signal processing are discussed in this paper. Standard averaging technique is used in the implemented algorithm. The final result speaks about the hearing capacity of a patient. The proof that the usage of microphone arrays leads to better SNR values than using a single microphone in an OAE probe, is successfully carried out in this work.

  11. Electromagnetic modeling and resonant detectors and arrays

    NASA Astrophysics Data System (ADS)

    Choi, K. K.; Sun, J.; DeCuir, E. A.; Olver, K. A.; Wijewarnasuriya, P.

    2015-05-01

    We recently developed a finite element three-dimensional electromagnetic model for quantum efficiency (QE) computation. It is applicable to any arbitrary detector geometry and materials. Using this model, we can accurately account for the open literature experimental results that we have investigated, which include those from GaAs solar cells, GaSb type-II superlattices, and GaAs quantum wells. We applied the model to design a photon trap to increase detector QE. By accumulating and storing incident light in the resonator-QWIP structure, we observed experimental QE as high as 71%. This improvement shows that we are now able to fully determine the optical properties of QWIPs. For example, we can design QWIPs to detect at certain wavelengths with certain bandwidths. To illustrate this capability, we designed QWIPs with its QE spectrum matching well with the transmission spectrum of a medium. We subsequently produced several focal plane arrays according to these designs with 640 × 512 and 1 K × 1 K formats. In this paper, we will compare the modeled QE and the experimental results obtained from single detectors as well as FPAs.

  12. Advanced ACTPol Cryogenic Detector Arrays and Readout

    NASA Astrophysics Data System (ADS)

    Henderson, S. W.; Allison, R.; Austermann, J.; Baildon, T.; Battaglia, N.; Beall, J. A.; Becker, D.; De Bernardis, F.; Bond, J. R.; Calabrese, E.; Choi, S. K.; Coughlin, K. P.; Crowley, K. T.; Datta, R.; Devlin, M. J.; Duff, S. M.; Dunkley, J.; Dünner, R.; van Engelen, A.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Hills, F.; Hilton, G. C.; Hincks, A. D.; Hloẑek, R.; Ho, S. P.; Hubmayr, J.; Huffenberger, K.; Hughes, J. P.; Irwin, K. D.; Koopman, B. J.; Kosowsky, A. B.; Li, D.; McMahon, J.; Munson, C.; Nati, F.; Newburgh, L.; Niemack, M. D.; Niraula, P.; Page, L. A.; Pappas, C. G.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sherwin, B. D.; Sievers, J. L.; Simon, S. M.; Spergel, D. N.; Staggs, S. T.; Stevens, J. R.; Thornton, R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope, adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background anisotropies—imaged in intensity and polarization at few arcminute-scale resolution—will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the Advanced ACTPol cryogenic detector arrays.

  13. Advanced ACTPol Cryogenic Detector Arrays and Readout

    NASA Technical Reports Server (NTRS)

    Henderson, S.W.; Allison, R.; Austermann, J.; Baildon, T.; Battaglia, N.; Beall, J. A.; Becker, D.; De Bernardis, F.; Bond, J. R.; Wollack, E. J.

    2016-01-01

    Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope, adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background anisotropies-imaged in intensity and polarization at few arcminute-scale resolution-will enable precision cosmological constraints and also awide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the AdvancedACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the AdvancedACTPol cryogenic detector arrays.

  14. Multiwavelength infrared focal plane array detector

    NASA Technical Reports Server (NTRS)

    Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)

    1995-01-01

    A multiwavelength focal plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y<1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.

  15. Fabrication of Pop-up Detector Arrays on Si Wafers

    NASA Technical Reports Server (NTRS)

    Li, Mary J.; Allen, Christine A.; Gordon, Scott A.; Kuhn, Jonathan L.; Mott, David B.; Stahle, Caroline K.; Wang, Liqin L.

    1999-01-01

    High sensitivity is a basic requirement for a new generation of thermal detectors. To meet the requirement, close-packed, two-dimensional silicon detector arrays have been developed in NASA Goddard Space Flight Center. The goal of the task is to fabricate detector arrays configured with thermal detectors such as infrared bolometers and x-ray calorimeters to use in space fliGht missions. This paper focuses on the fabrication and the mechanical testing of detector arrays in a 0.2 mm pixel size, the smallest pop-up detectors being developed so far. These array structures, nicknamed "PUDS" for "Pop-Up Detectors", are fabricated on I pm thick, single-crystal, silicon membranes. Their designs have been refined so we can utilize the flexibility of thin silicon films by actually folding the silicon membranes to 90 degrees in order to obtain close-packed two-dimensional arrays. The PUD elements consist of a detector platform and two legs for mechanical support while also serving as electrical and thermal paths. Torsion bars and cantilevers connecting the detector platform to the legs provide additional flexures for strain relief. Using micro-electromechanical structure (MEMS) fabrication techniques, including photolithography, anisotropic chemical etching, reactive-ion etching, and laser dicing, we have fabricated PLTD detector arrays of fourteen designs with a variation of four parameters including cantilever length, torsion bar length and width, and leg length. Folding tests were conducted to test mechanical stress distribution for the array structures. We obtained folding yields and selected optimum design parameters to reach minimal stress levels. Computer simulation was also employed to verify mechanical behaviors of PUDs in the folding process. In addition, scanning electron microscopy was utilized to examine the flatness of detectors and the alignment of detector pixels in arrays. The fabrication of thermistors and heaters on the pop-up detectors is under way

  16. The Impact of Array Detectors on Raman Spectroscopy

    ERIC Educational Resources Information Center

    Denson, Stephen C.; Pommier, Carolyn J. S.; Denton, M. Bonner

    2007-01-01

    The impact of array detectors in the field of Raman spectroscopy and all low-light-level spectroscopic techniques is examined. The high sensitivity of array detectors has allowed Raman spectroscopy to be used to detect compounds at part per million concentrations and to perform Raman analyses at advantageous wavelengths.

  17. Detector arrays for low-background space infrared astronomy

    NASA Technical Reports Server (NTRS)

    Mccreight, C. R.; Mckelvey, M. E.; Goebel, J. H.; Anderson, G. M.; Lee, J. H.

    1986-01-01

    The status of development and characterization tests of integrated infrared detector array technology for astronomy applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, with hybrid silicon multiplexers. Laboratory test results and successful astronomy imagery have established the usefulness of integrated arrays in low-background astronomy applications.

  18. Detector arrays for low-background space infrared astronomy

    NASA Technical Reports Server (NTRS)

    Mccreight, C. R.; Mckelvey, M. E.; Goebel, J. H.; Anderson, G. M.; Lee, J. H.

    1986-01-01

    The status of development and characterization tests of integrated infrared detector array technology for astronomy applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, with hybrid silicon multiplexers. Laboratary test results and successful astronomy imagery have established the usefulness of integrated arrays in low-background astronomy applications.

  19. Position sensitivity of MAMA detectors. [Multi-Anode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Morgan, J. S.; Slater, D. S.; Timothy, J. G.; Jenkins, E. B.

    1988-01-01

    The results of laboratory and telescopic measurements of the position sensitivity of a visible MAMA detector utilizing a 'coarse-fine' array are presented. The photometric accuracy of this detector was determined under point source illumination. It was found that computed centroid positions are accurate across the entire array to within 0.04 pixels.

  20. Modulation transfer function of a trapezoidal pixel array detector

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Guo, Rongli; Ni, Jinping; Dong, Tao

    2016-01-01

    The modulation transfer function (MTF) is the tool most commonly used for quantifying the performance of an electro-optical imaging system. Recently, trapezoid-shaped pixels were designed and used in a retina-like sensor in place of rectangular-shaped pixels. The MTF of a detector with a trapezoidal pixel array is determined according to its definition. Additionally, the MTFs of detectors with differently shaped pixels, but the same pixel areas, are compared. The results show that the MTF values of the trapezoidal pixel array detector are obviously larger than those of rectangular and triangular pixel array detectors at the same frequencies.

  1. A 16 x 16 element extrinsic silicon detector array

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Two bismuth-doped silicon accumulation-mode charge-injection device (AMCID) infrared detector arrays are studied. The geometry and composition of the arrays, and a description of the cold and warm electronics components of the system are described. Instructions for setting up and operating the array system, plus results of a functional test, are included.

  2. Results from the Puebla extensive air shower detector array

    NASA Astrophysics Data System (ADS)

    Salazar, H.; Martinez, O.; Moreno, E.; Cotzomi, J.; Villaseñor, L.; Saavedrac, O.

    2003-07-01

    We describe the design and operation of the first stage of the EAS-UAP extensive air shower array, as a detector of very high energy cosmic rays ( Eo > 10 14eV). The array is located at the Campus of Puebla University and consists of 18 liquid scintillator detectors, with an active surface of 1 m2 each and a detector spacing of 20 m in a square grid. In this report we discuss the stability and the calibration of the detector array, as derived from the 10 detectors in operation in the first stage. The main characteristics of the array allow us also to use it as an educational and training facility. First distributions of the arrival direction and the lateral shower srpead are also given.

  3. PbS-PbSe IR detector arrays

    NASA Technical Reports Server (NTRS)

    Barrett, John R. (Inventor)

    1986-01-01

    A silicon wafer is provided which does not employ individually bonded leads between the IR sensitive elements and the input stages of multiplexers. The wafer is first coated with lead selenide in a first detector array area and is thereafter coated with lead sulfide within a second detector array area. The described steps result in the direct chemical deposition of lead selenide and lead sulfide upon the silicon wafer to eliminate individual wire bonding, bumping, flip chipping, planar interconnecting methods of connecting detector array elements to silicon chip circuitry, e.g., multiplexers, to enable easy fabrication of very long arrays. The electrode structure employed, produces an increase in the electrical field gradient between the electrodes for a given volume of detector material, relative to conventional electrode configurations.

  4. Particle Identification in the NIMROD-ISiS Detector Array

    SciTech Connect

    Wuenschel, S.; Hagel, K.; May, L. W.; Wada, R.; Yennello, S. J.

    2009-03-10

    Interest in the influence of the neutron-to-proton (N/Z) ratio on multifragmenting nuclei has demanded an improvement in the capabilities of multi-detector arrays as well as the companion analysis methods. The particle identification method used in the NIMROD-ISiS 4{pi} array is described. Performance of the detectors and the analysis method are presented for the reaction of {sup 86}Kr+{sup 64}Ni at 35 MeV/u.

  5. Scientific Applications and Promise of Cryogenic Detector Arrays

    NASA Astrophysics Data System (ADS)

    Moseley, Samuel Harvey

    2009-12-01

    During the past year, the first results from a new generation of instruments based on kilopixel-scale arrays of cryogenic detectors have been released. I will review the history of low temperature detector arrays which has enabled this development, the science which has driven this rapid progress, describe the instruments now in operation and their initial scientific results, and speculate on the developments we may see in the next decade.

  6. Gamma-spectrometry with Compton suppressed detectors arrays

    SciTech Connect

    Schueck, C.; Hannachi, F.; Chapman, R.; Lisle, J.C.; Mo, J.N.; Paul, E.; Love, D.J.G.; Nolan, P.J.; Nelson, A.H.; Walker, P.M.

    1985-01-01

    Recent results of experiments performed with two different Compton-suppressed detectors arrays in Daresbury and Berkeley (/sup 163,164/Yb and /sup 154/Er, respectively), are presented together with a brief description of the national French array presently under construction in Strasbourg. 25 refs., 15 figs.

  7. Rubicon - a New Diode Array Detector System

    NASA Astrophysics Data System (ADS)

    Schmidt-Kaler, T.; Rudolph, R.; Tug, H.

    A photon-counting system with a 512-channel parallel output digital image tube is presented. Electronics developed separately for each detector channel as well as data aquisition are optimized for low power consumption and high counting rates. This detector, characterized by wide dynamic range, very low noise and high photometric accuracy, is especially suitable for spectrophotometry and calibrations.

  8. Low-background detector arrays for infrared astronomy

    NASA Technical Reports Server (NTRS)

    Mccreight, C. R.; Estrada, J. A.; Goebel, J. H.; Mckelvey, M. E.; Mckibbin, D. D.; Mcmurray, R. E., Jr.; Weber, T. T.

    1989-01-01

    The status of a program which develops and characterizes integrated infrared (IR) detector array technology for space astronomical applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, coupled to silicon readout electronics. Low-background laboratory test results include measurements of responsivity, noise, dark current, temporal response, and the effects of gamma-radiation. In addition, successful astronomical imagery has been obtained on some arrays from this program. These two aspects of the development combine to demonstrate the strong potential for integrated array technology for IR space astronomy.

  9. A Study of Lane Differentiation Using An Array of Detectors.

    SciTech Connect

    McKigney E. A.; Gholkar, R. V.; Vega, D. A.

    2004-01-01

    The authors discuss a method for locating a radioactive source in the context of determining which lane a source is in on a roadway. This method is appropriate for use over a large range of source velocities, and could provide an advance alarm prior to a vehicle passing a portal monitor. This is a novel method which uses data from the entire array simultaneously to locate the source, rather than relying on only one or two sensors. A description of the underlying method will be given, along with results from five and six detector arrays. The five detector array was used mainly for static tests. The six detector array was used for dynamic tests, including slow movement of a source in a vehicle.

  10. LWIR detector arrays based on nipi superlattices

    NASA Technical Reports Server (NTRS)

    Maserjian, J.; Grunthaner, F. J.; Elliott, C. T.

    1990-01-01

    It is proposed that nipi superlattice structures in InSb or InAs can be grown with modern techniques to achieve tunable and stable LWIR detectors with high performance. Key device and material considerations for the application of such nipi superlattices to LWIR detectors are examined. It is shown that practical absorption coefficients (of about 100/cm) can be achieved with high doping concentrations (of about 10 to the 19th/cu cm) achievable in these materials. In particular, recent delta doping techniques being developed in molecular beam epitaxy offer promise of higher doping concentrations, improved uniformity, and greater flexibility in tailoring the structures for optimum detector performance.

  11. Bolometeric detector arrays for CMB polarimetry

    NASA Technical Reports Server (NTRS)

    Kuo, C. L.; Bock, J. J.; Day, P.; Goldin, A.; Golwala, S.; Holmes, W.; Irwin, K.; Kenyon, M.; Lange, A. E.; LeDuc, H. G.; Rossinot, P.; Sterb, J.; Vayonakis, A.; Wang, G.; Yun, M.; Zmuidzinas, J.

    2005-01-01

    We describe the development of antenna coupled bolometers for CMB polarization experiments. The necessary components of a bolometric CMB polarimeter - a beam forming element, a band defining filter, and detectors - are all fabricated on a silicon chip with photolithography.

  12. Surface detector array for the Pierre Auger observatory

    NASA Astrophysics Data System (ADS)

    Salazar, H.; Garipov, G. K.; Khrenov, B. A.; Martínez, O.; Moreno, E.; Villaseñor, L.; Zepeda, A.

    2001-05-01

    The Pierre Auger international collaboration will install two observatories, one in the southern hemisphere and other in the northern hemisphere. Each observatory will consist of two different subsystem: a surface detector array of about 1600 water Cherenkov detectors (WCD) and a set of fluorescence eyes to measure the longitudinal development of air showers. The large area covered by the surface detectors requires efficient calibration and monitoring methods that can be implemented remotely. We present several complementary methods to calibrate and monitor the performance of the individual surface detector stations. We also present some results of the studies made with a full size prototype tank in Puebla, Mexico and in Malargue, Argentina. .

  13. Photon counting detector array algorithms for deep space optical communications

    NASA Astrophysics Data System (ADS)

    Srinivasan, Meera; Andrews, Kenneth S.; Farr, William H.; Wong, Andre

    2016-03-01

    For deep-space optical communications systems utilizing an uplink optical beacon, a single-photon-counting detector array on the flight terminal can be used to simultaneously perform uplink tracking and communications as well as accurate downlink pointing at photon-starved (pW=m2) power levels. In this paper, we discuss concepts and algorithms for uplink signal acquisition, tracking, and parameter estimation using a photon-counting camera. Statistical models of detector output data and signal processing algorithms are presented, incorporating realistic effects such as Earth background and detector/readout blocking. Analysis and simulation results are validated against measured laboratory data using state-of-the-art commercial photon-counting detector arrays, demonstrating sub-microradian tracking errors under channel conditions representative of deep space optical links.

  14. Integrated Miniature Arrays of Optical Biomolecule Detectors

    NASA Technical Reports Server (NTRS)

    Iltchenko, Vladimir; Maleki, Lute; Lin, Ying; Le, Thanh

    2009-01-01

    Integrated miniature planar arrays of optical sensors for detecting specific biochemicals in extremely small quantities have been proposed. An array of this type would have an area of about 1 cm2. Each element of the array would include an optical microresonator that would have a high value of the resonance quality factor (Q . 107). The surface of each microresonator would be derivatized to make it bind molecules of a species of interest, and such binding would introduce a measurable change in the optical properties of the microresonator. Because each microresonator could be derivatized for detection of a specific biochemical different from those of the other microresonators, it would be possible to detect multiple specific biochemicals by simultaneous or sequential interrogation of all the elements in the array. Moreover, the derivatization would make it unnecessary to prepare samples by chemical tagging. Such interrogation would be effected by means of a grid of row and column polymer-based optical waveguides that would be integral parts of a chip on which the array would be fabricated. The row and column polymer-based optical waveguides would intersect at the elements of the array (see figure). At each intersection, the row and column waveguides would be optically coupled to one of the microresonators. The polymer-based waveguides would be connected via optical fibers to external light sources and photodetectors. One set of waveguides and fibers (e.g., the row waveguides and fibers) would couple light from the sources to the resonators; the other set of waveguides and fibers (e.g., the column waveguides and fibers) would couple light from the microresonators to the photodetectors. Each microresonator could be addressed individually by row and column for measurement of its optical transmission. Optionally, the chip could be fabricated so that each microresonator would lie inside a microwell, into which a microscopic liquid sample could be dispensed.

  15. SRAM As An Array Of Energetic-Ion Detectors

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G.; Blaes, Brent R.; Lieneweg, Udo; Nixon, Robert H.

    1993-01-01

    Static random-access memory (SRAM) designed for use as array of energetic-ion detectors. Exploits well-known tendency of incident energetic ions to cause bit flips in cells of electronic memories. Design of ion-detector SRAM involves modifications of standard SRAM design to increase sensitivity to ions. Device fabricated by use of conventional complementary metal oxide/semiconductor (CMOS) processes. Potential uses include gas densimetry, position sensing, and measurement of cosmic-ray spectrum.

  16. Uncooled Infrared Detector Arrays With Electrostatically Levitated Sensing Elements

    DTIC Science & Technology

    2005-03-28

    detectors"" vout operating at room temperature . Their resistance changes V2 Ni l following a temperature rise from the absorption of incident radiation...advantages of this approach are: Although in recent times, uncooled microbolometer 1) The detector temperature is not disturbed by thermal arrays have seen...levels by performing the deposition at an elevated temperature . The technology developed here was applied to a new class of acoustic transducer, a

  17. Status of the Neutral Current Detector Array at SNO

    NASA Astrophysics Data System (ADS)

    Cox, Adam

    2003-05-01

    The third phase of data taking at the Sudbury Neutrino Observatory (SNO) is currently scheduled to begin in the autumn of 2003 with the installation of the Neutral Current Detectors (NCD). The NCDs, an array of ^3He proportional counters, will make an independent measurement of the flux of ^8B solar neutrinos at SNO. The latest results in experimental neutrino physics have given the SNO collaboration the opportunity to maximize the physics capabilities of SNO by deploying just half of the initially proposed NCD array. In order to minimize backgrounds, only the best counters with the lowest intrinsic radioactivity have been selected for deployment into the SNO detector.

  18. Detectors based on silicon photomultiplier arrays for medical imaging applications

    SciTech Connect

    Llosa, G.; Barrio, J.; Cabello, J.; Lacasta, C.; Oliver, J. F.; Stankova, V.; Solaz, C.

    2011-07-01

    Silicon photomultipliers (SiPMs) have experienced a fast development and are now employed in different research fields. The availability of 2D arrays that provide information of the interaction position in the detector has had a high interest for medical imaging. Continuous crystals combined with segmented photodetectors can provide higher efficiency than pixellated crystals and very high spatial resolution. The IRIS group at IFIC is working on the development of detector heads based on continuous crystals coupled to SiPM arrays for different applications, including a small animal PET scanner in collaboration with the Univ. of Pisa and INFN Pisa, and a Compton telescope for dose monitoring in hadron therapy. (authors)

  19. Detector array evaluation and figures of merit

    NASA Technical Reports Server (NTRS)

    Dereniak, Eustace L.

    1990-01-01

    The commonly used methods to evaluate the performance of a two-dimensional focal-plane array using charge transfer devices are reviewed. Two figures of merit that attempt to combine quantum efficiency, read noise and dark-current generation into a single parameter are discussed. The figures of merit are suggested as possible alternatives to the D asterisk.

  20. Si:Bi switched photoconducttor infrared detector array

    NASA Technical Reports Server (NTRS)

    Eakin, C. E.

    1983-01-01

    A multiplexed infrared detector array is described. The small demonstration prototype consisted of two cryogenically cooled, bismuth doped silicon, extrinsic photoconductor pixels multiplexed onto a single output channel using an on focal plane switch integration sampling technique. Noise levels of the order of 400 to 600 rms electrons per sample were demonstrated for this chip and wire hybrid version.

  1. A broadband superconducting detector suitable for use in large arrays.

    PubMed

    Day, Peter K; LeDuc, Henry G; Mazin, Benjamin A; Vayonakis, Anastasios; Zmuidzinas, Jonas

    2003-10-23

    Cryogenic detectors are extremely sensitive and have a wide variety of applications (particularly in astronomy), but are difficult to integrate into large arrays like a modern CCD (charge-coupled device) camera. As current detectors of the cosmic microwave background (CMB) already have sensitivities comparable to the noise arising from the random arrival of CMB photons, the further gains in sensitivity needed to probe the very early Universe will have to arise from large arrays. A similar situation is encountered at other wavelengths. Single-pixel X-ray detectors now have a resolving power of DeltaE < 5 eV for single 6-keV photons, and future X-ray astronomy missions anticipate the need for 1,000-pixel arrays. Here we report the demonstration of a superconducting detector that is easily fabricated and can readily be incorporated into such an array. Its sensitivity is already within an order of magnitude of that needed for CMB observations, and its energy resolution is similarly close to the targets required for future X-ray astronomy missions.

  2. A Broadband Superconducting Detector Suitable for Use in Large Arrays

    NASA Technical Reports Server (NTRS)

    Day, Peter K.; LeDuc, Henry G.; Mazin, Benjamin A.; Vayonakis, Anastasios; Zmuldzinas, Jonas

    2003-01-01

    Cryogenic detectors are extremely sensitive and have a wide variety of applications (particularly in astronomy), but are difficult to integrate into large arrays like a modern CCD (charge-coupled device) camera. As current detectors of the cosmic microwave background (CMB) already have sensitivities comparable to the noise arising from the random arrival of CMB photons, the further gains in sensitivity needed to probe the very early Universe will have to arise from large arrays. A similar situation is encountered at other wavelengths. Single-pixel X-ray detectors now have a resolving power of (Delta)E < 5 eV for single 6-keV photons, and future X-ray astronomy missions anticipate the need for 1,000-pixel arrays. Here we report the demonstration of a superconducting detector that is easily fabricated and can readily be incorporated into such an array. Its sensitivity is already within an order of magnitude of that needed for CMB observations, and its energy resolution is similarly close to the targets required for future X-ray astronomy missions.

  3. Conceptual design of a hybrid Ge:Ga detector array

    NASA Technical Reports Server (NTRS)

    Parry, C. M.

    1984-01-01

    For potential applications in space infrared astronomy missions such as the Space Infrared Telescope Facility and the Large Deployable Reflector, integrated arrays of long-wavelength detectors are desired. The results of a feasibility study which developed a design for applying integrated array techniques to a long-wavelength (gallium-doped germanium) material to achieve spectral coverage between 30 and 200 microns are presented. An approach which builds up a two-dimensional array by stacking linear detector modules is presented. The spectral response of the Ge:Ga detectors is extended to 200 microns by application of uniaxial stress to the stack of modules. The detectors are assembled with 1 mm spacing between the elements. Multiplexed readout of each module is accomplished with integration sampling of a metal-oxide-semiconductor (MOS) switch chip. Aspects of the overall design, including the anticipated level of particle effects on the array in the space environment, a transparent electrode design for 200 microns response, estimates of optical crosstalk, and mechanical stress design calculations are included.

  4. First Results from the Telescope Array RAdar (TARA) Detector

    NASA Astrophysics Data System (ADS)

    Myers, Isaac

    2014-03-01

    The TARA cosmic ray detector has been in operation for about a year and a half. This bi-static radar detector was designed with the goal of detecting cosmic rays in coincidence with Telescope Array (TA). A new high power (25 kW, 5 MW effective radiated power) transmitter and antenna array and 250 MHz fPGA-based DAQ have been operational since August 2013. The eight-Yagi antenna array broadcasts a 54.1 MHz tone across the TA surface detector array toward our receiver station 50 km away at the Long Ridge fluorescence detector. Receiving antennas feed an intelligent DAQ that self-adjusts to the fluctuating radio background and which employs a bank of matched filters that search in real-time for chirp radar echoes. Millions of triggers have been collected in this mode. A second mode is a forced trigger scheme that uses the trigger status of the fluorescence telescope. Of those triggers collected in FD-triggered mode, about 800 correspond with well-reconstructed TA events. I will describe recent advancements in calibrating key components in the transmitter and receiver RF chains and the analysis of FD-triggered data. Work supported by W.M. Keck Foundation and NSF.

  5. High resolution decoding of Multi-Anode Microchannel Array detectors

    NASA Technical Reports Server (NTRS)

    Kasle, David B.; Morgan, Jeffrey S.

    1991-01-01

    The Multi-Anode Microchannel Array (MAMA) is a photon counting detector which utilizes a photocathode for photon to electron conversion, a microchannel plate (MCP) for signal amplification and a proximity focused anode array for position sensitivity. The detector electronics decode the position of an event through coincidence discrimination. The decoding algorithm which associates a given event with the appropriate pixel is determined by the geometry of the array. A new algorithm incorporated into a CMOS Application Specific Integrated Circuit (ASIC) decoder which improves the pixel spatial resolution is described. The new algorithm does not degrade the detector throughput and does not require any modifications to the detector tube. The standard MAMA detector has a pixel size of 25 x 25 square microns, but with the new decoder circuit the pixel size is reduced to 12.5 x 12.5 square microns. We have built the first set of decode electronics utilizing the new ASIC chips and report here on the first imaging tests of this system.

  6. Photon counting photodiode array detector for far ultraviolet (FUV) astronomy

    NASA Technical Reports Server (NTRS)

    Hartig, G. F.; Moos, H. W.; Pembroke, R.; Bowers, C.

    1982-01-01

    A compact, stable, single-stage intensified photodiode array detector designed for photon-counting, far ultraviolet astronomy applications employs a saturable, 'C'-type MCP (Galileo S. MCP 25-25) to produce high gain pulses with a narrowly peaked pulse height distribution. The P-20 output phosphor exhibits a very short decay time, due to the high current density of the electron pulses. This intensifier is being coupled to a self-scanning linear photodiode array which has a fiber optic input window which allows direct, rigid mechanical coupling with minimal light loss. The array was scanned at a 250 KHz pixel rate. The detector exhibits more than adequate signal-to-noise ratio for pulse counting and event location. Previously announced in STAR as N82-19118

  7. Applications of pyroelectric materials in array-based detectors.

    PubMed

    Holden, Anthony J

    2011-09-01

    The development of low-cost, uncooled (room temperature operation) thermal detector arrays has been accelerating in recent years and now commercial products are becoming widely available. As costs come down and volumes rise, these devices are entering the consumer marketplace, providing everything from sophisticated security and people-monitoring devices to hand-held thermal imagers for preventative maintenance and building inspection. Two technologies have established significant market shares in uncooled thermal detector array products. These are resistive microbolometers and pyroelectric ceramics. To address the true mass market, the pyroelectric arrays offer significant cost advantage. In this paper, recent developments in a variety of products based on pyroelectric ceramic arrays are described and their performance and applicability are compared and contrasted with competing technologies. This includes the use of low-element-count arrays for applications in people counting and queue measurement, and the drive for cost-effective imaging arrays for mass-market thermal imaging. The technical challenges in materials production, device development, and low-cost manufacture are reviewed and future opportunities and challenges are outlined.

  8. Order-sorting filter transmittance measured with an array detector

    NASA Technical Reports Server (NTRS)

    Heaney, James B.; Bradley, Scott E.; Bly, Vincent T.; Ewin, Audrey J.; La, Anh T.

    1993-01-01

    The simultaneous measurement of the spectrally and spatially variant transmittance of a linear variable order-sorting filter in a manner that closely resembles its conditions of actual use is described. The transmittance of a prototype order-sorting filter was measured in the 400- to 880-nm wavelength region by illuminating it with the output beam of a spectrophotometer while the filter was attached to the front of a 30 x 32 pixel silicon array detector. The filter was designed to be used in the output beam of a grating spectrometer to prevent the dispersal of higher diffracted orders onto an array detector. Areas of the filter that were spatially matched to the corresponding detector pixel column had measured peak transmittances of about 90 percent that were uniform to within +/- 1.5 percent along a given column. Transmittances for incident wavelengths shorter than the desired bandpass, corresponding to the order overlap region, were measured in the 0.003 range. Line spread function measurements made with the array detector indicated no significant beam spreading caused by inserting the filter into the beam.

  9. Heterodyne detection with mismatch correction based on array detector

    NASA Astrophysics Data System (ADS)

    Dong, Hongzhou; Li, Guoqiang; Yang, Ruofu; Yang, Chunping; Ao, Mingwu

    2016-07-01

    Based on an array detector, a new heterodyne detection system, which can correct the mismatches of amplitude and phase between signal and local oscillation (LO) beams, is presented in this paper. In the light of the fact that, for a heterodyne signal, there is a certain phase difference between the adjacent two samples of analog-to-digital converter (ADC), we propose to correct the spatial phase mismatch by use of the time-domain phase difference. The corrections can be realized by shifting the output sequences acquired from the detector elements in the array, and the steps of the shifting depend on the quantity of spatial phase mismatch. Numerical calculations of heterodyne efficiency are conducted to confirm the excellent performance of our system. Being different from previous works, our system needs not extra optical devices, so it provides probably an effective means to ease the problem resulted from the mismatches.

  10. Heterodyne detection with mismatch correction base on array detector

    NASA Astrophysics Data System (ADS)

    Hongzhou, Dong; Guoqiang, Li; Ruofu, Yang; Chunping, Yang; Mingwu, Ao

    2016-07-01

    Based on an array detector, a new heterodyne detection system, which can correct the mismatches of amplitude and phase between signal and local oscillation (LO) beams, is presented in this paper. In the light of the fact that, for a heterodyne signal, there is a certain phase difference between the adjacent two samples of analog-to-digital converter (ADC), we propose to correct the spatial phase mismatch by use of the time-domain phase difference. The corrections can be realized by shifting the output sequences acquired from the detector elements in the array, and the steps of the shifting depend on the quantity of spatial phase mismatch. Numerical calculations of heterodyne efficiency are conducted to confirm the excellent performance of our system. Being different from previous works, our system needs not extra optical devices, so it provides probably an effective means to ease the problem resulted from the mismatches.

  11. A new detector array for charged particle spectroscopy

    NASA Astrophysics Data System (ADS)

    Cowin, R. L.; Watson, D. L.; Chappell, S. P. G.; Clarke, N. M.; Freer, M.; Fulton, B. R.; Cunningham, R. A.; Curtis, N.; Dillon, G. K.; Lilley, J.; Jones, C. D.; Lee, P.; Rae, W. D. M.

    1999-02-01

    A compact and highly segmented detector array consisting of 44 gas-silicon-caesium iodide, position sensitive, particle identification detector telescopes and up to 10 position-sensitive, silicon strip detectors has been constructed for the study of light-ion-heavy-ion reactions including cluster break-up in the energy range 5-15MeV/nucleon. The detectors are housed in a purpose built vacuum chamber. The telescopes are placed in fixed positions, covering the forward hemisphere from 3 to 30° in the laboratory with the target placed at 535mm from the front of the telescopes or 6-52° with the target placed at 215mm. The strip detectors are placed in any of 30 fixed positions in the forward hemisphere. For 85MeV 12C ions the telescope energy resolution (gas plus silicon) is 345keV with an angular resolution of 0.03°. Using the gas-silicon section ions with Z up to 21 can be identified. For ions that pass through the silicon isotopic identification is achieved using the silicon-CsI combination. The strip detector energy resolution is 200keV, with an angular resolution of 0.1°.

  12. The Telescope Array Middle Drum fluorescence detector simulation on GPUs

    NASA Astrophysics Data System (ADS)

    Abu-Zayyad, Tareq; Telescope-Array Collaboration

    2014-06-01

    In recent years, the Graphics Processing Unit (GPU) has been recognized and widely used as an accelerator for many scientific calculations. In general, problems amenable to parallelization are ones that benefit most from the use of GPUs. The Monte Carlo simulation of fluorescence detector response to air showers presents many opportunities for parallelization. In this paper we report on a Monte Carlo program used for the simulation of the Telescope Array Fluorescence Detector located at the Middle Drum site which uses GPU acceleration. All of the physics simulation from shower development, light production and atmospheric attenuation, as well as, the realistic detector optics and electronics simulations are done on the GPU. A detailed description of the code implementation is given, and results on the accuracy and performance of the simulation are presented as well. Improvements in computational throughput in excess of 50× are reported and the accuracy of the results is on par with the CPU implementation of the simulation.

  13. Imaging MAMA detector systems. [Multi-Anode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.

    1990-01-01

    Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

  14. READOUT SYSTEM FOR ARRAYS OF FRISCH-RING CDZNTE DETECTORS.

    SciTech Connect

    CUI, Y.; BOLOTNIKOV, A.E.; CAMARDA, G.S.; DE GERONIMO, G.; O'CONNOR, P.; JAMES, R.B.; KARGAR, A.; HARRISON, M.J.; MCGREGOR, D.S.

    2006-10-29

    Frisch-ring CdZnTe detectors have demonstrated good energy resolution for identifying isotopes, <1% FWHM at 662 keV, and good efficiency for detecting gamma rays. We will fabricate and test at Brookhaven National Laboratory an integrated module of a 64-element array of 6 x 6 x 12 mm{sup 3} Frisch-ring detectors, coupled with a readout electronics system. It supports 64 readout channels, and includes front-end electronics, signal processing circuit, USB interface and high-voltage power supply. The data-acquisition software is used to process the data stream, which includes amplitude and timing information for each detected event. This paper describes the design and assembly of the detector modules, readout electronics, and a conceptual prototype system. Some test results are also reported.

  15. Distributed Antenna-Coupled TES for FIR Detectors Arrays

    NASA Technical Reports Server (NTRS)

    Day, Peter K.; Leduc, Henry G.; Dowell, C. Darren; Lee, Richard A.; Zmuidzinas, Jonas

    2007-01-01

    We describe a new architecture for a superconducting detector for the submillimeter and far-infrared. This detector uses a distributed hot-electron transition edge sensor (TES) to collect the power from a focal-plane-filling slot antenna array. The sensors lay directly across the slots of the antenna and match the antenna impedance of about 30 ohms. Each pixel contains many sensors that are wired in parallel as a single distributed TES, which results in a low impedance that readily matches to a multiplexed SQUID readout These detectors are inherently polarization sensitive, with very low cross-polarization response, but can also be configured to sum both polarizations. The dual-polarization design can have a bandwidth of 50The use of electron-phonon decoupling eliminates the need for micro-machining, making the focal plane much easier to fabricate than with absorber-coupled, mechanically isolated pixels. We discuss applications of these detectors and a hybridization scheme compatible with arrays of tens of thousands of pixels.

  16. The detector calibration system for the CUORE cryogenic bolometer array

    NASA Astrophysics Data System (ADS)

    Cushman, Jeremy S.; Dally, Adam; Davis, Christopher J.; Ejzak, Larissa; Lenz, Daniel; Lim, Kyungeun E.; Heeger, Karsten M.; Maruyama, Reina H.; Nucciotti, Angelo; Sangiorgio, Samuele; Wise, Thomas

    2017-02-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic experiment designed to search for neutrinoless double-beta decay of 130Te and other rare events. The CUORE detector consists of 988 TeO2 bolometers operated underground at 10 mK in a dilution refrigerator at the Laboratori Nazionali del Gran Sasso. Candidate events are identified through a precise measurement of their energy. The absolute energy response of the detectors is established by the regular calibration of each individual bolometer using gamma sources. The close-packed configuration of the CUORE bolometer array combined with the extensive shielding surrounding the detectors requires the placement of calibration sources within the array itself. The CUORE Detector Calibration System is designed to insert radioactive sources into and remove them from the cryostat while respecting the stringent heat load, radiopurity, and operational requirements of the experiment. This paper describes the design, commissioning, and performance of this novel source calibration deployment system for ultra-low-temperature environments.

  17. Digital readouts for large microwave low-temperature detector arrays

    NASA Astrophysics Data System (ADS)

    Mazin, Benjamin A.; Day, Peter K.; Irwin, Kent D.; Reintsema, Carl D.; Zmuidzinas, Jonas

    2006-04-01

    Over the last several years many different types of low-temperature detectors (LTDs) have been developed that use a microwave resonant circuit as part of their readout. These devices include microwave kinetic inductance detectors (MKID), microwave SQUID readouts for transition edge sensors (TES), and NIS bolometers. Current readout techniques for these devices use analog frequency synthesizers and IQ mixers. While these components are available as microwave integrated circuits, one set is required for each resonator. We are exploring a new readout technique for this class of detectors based on a commercial-off-the-shelf technology called software defined radio (SDR). In this method a fast digital to analog (D/A) converter creates as many tones as desired in the available bandwidth. Our prototype system employs a 100 MS/s 16-bit D/A to generate an arbitrary number of tones in 50 MHz of bandwidth. This signal is then mixed up to the desired detector resonant frequency (˜10 GHz), sent through the detector, then mixed back down to baseband. The baseband signal is then digitized with a series of fast analog to digital converters (80 MS/s, 14-bit). Next, a numerical mixer in a dedicated integrated circuit or FPGA mixes the resonant frequency of a specified detector to 0 Hz, and sends the complex detector output over a computer bus for processing and storage. In this paper we will report on our results in using a prototype system to readout a MKID array, including system noise performance, X-ray pulse response, and cross-talk measurements. We will also discuss how this technique can be scaled to read out many thousands of detectors.

  18. Topological detector: measuring continuous dosimetric quantities with few-element detector array

    NASA Astrophysics Data System (ADS)

    Han, Zhaohui; Brivio, Davide; Sajo, Erno; Zygmanski, Piotr

    2016-08-01

    A prototype topological detector was fabricated and investigated for quality assurance of radiation producing medical devices. Unlike a typical array or flat panel detector, a topological detector, while capable of achieving a very high spatial resolution, consists of only a few elements and therefore is much simpler in construction and more cost effective. The key feature allowing this advancement is a geometry-driven design that is customized for a specific dosimetric application. In the current work, a topological detector of two elements was examined for the positioning verification of the radiation collimating devices (jaws, MLCs, and blades etc). The detector was diagonally segmented from a rectangular thin film strip (2.5 cm  ×  15 cm), giving two contiguous but independent detector elements. The segmented area was the central portion of the strip measuring 5 cm in length. Under irradiation, signals from each detector element were separately digitized using a commercial multichannel data acquisition system. The center and size of an x-ray field, which were uniquely determined by the collimator positions, were shown mathematically to relate to the difference and sum of the two signals. As a proof of concept, experiments were carried out using slit x-ray fields ranging from 2 mm to 20 mm in size. It was demonstrated that, the collimator positions can be accurately measured with sub-millimeter precisions.

  19. Fast, High-Precision Readout Circuit for Detector Arrays

    NASA Technical Reports Server (NTRS)

    Rider, David M.; Hancock, Bruce R.; Key, Richard W.; Cunningham, Thomas J.; Wrigley, Chris J.; Seshadri, Suresh; Sander, Stanley P.; Blavier, Jean-Francois L.

    2013-01-01

    The GEO-CAPE mission described in NASA's Earth Science and Applications Decadal Survey requires high spatial, temporal, and spectral resolution measurements to monitor and characterize the rapidly changing chemistry of the troposphere over North and South Americas. High-frame-rate focal plane arrays (FPAs) with many pixels are needed to enable such measurements. A high-throughput digital detector readout integrated circuit (ROIC) that meets the GEO-CAPE FPA needs has been developed, fabricated, and tested. The ROIC is based on an innovative charge integrating, fast, high-precision analog-to-digital circuit that is built into each pixel. The 128×128-pixel ROIC digitizes all 16,384 pixels simultaneously at frame rates up to 16 kHz to provide a completely digital output on a single integrated circuit at an unprecedented rate of 262 million pixels per second. The approach eliminates the need for off focal plane electronics, greatly reducing volume, mass, and power compared to conventional FPA implementations. A focal plane based on this ROIC will require less than 2 W of power on a 1×1-cm integrated circuit. The ROIC is fabricated of silicon using CMOS technology. It is designed to be indium bump bonded to a variety of detector materials including silicon PIN diodes, indium antimonide (InSb), indium gallium arsenide (In- GaAs), and mercury cadmium telluride (HgCdTe) detector arrays to provide coverage over a broad spectral range in the infrared, visible, and ultraviolet spectral ranges.

  20. The development and test of multi-anode microchannel array detector systems. Part 2: Soft X-ray detectors

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1986-01-01

    Detector systems based on the high gain microchannel plate (MCP) electron multiplier were used extensively for imaging at soft X-ray wavelengths both on the ground and in space. The latest pulse counting electronic readout systems provide zero readout noise, spatial resolutions (FWHM) of 25 microns or better and can determine the arrival times of detected photons to an accuracy of the order of 100 ns. These systems can be developed to produce detectors with active areas of 100 nm in diameter or greater. The use of CsI photocathodes produces very high detective quantum efficiencies at wavelengths between about 100 and 1A (approximately 0.1 to 10 keV) with moderate energy resolution. The operating characteristics of the different types of soft X-ray MCP detector systems are described and the prospects for future developments are discussed.

  1. Bolometric Array Detectors for Space-Borne Astronomy

    NASA Technical Reports Server (NTRS)

    Lange, Andrew E.

    2000-01-01

    Funding from the NASA Innovative Research Grant was used to develop bolometric detectors. As described in the proposal, silicon nitride micromesh ('spider-web') absorbers had been demonstrated at U.C. Berkeley but not developed to be flight-worthy devices. We proceeded to first fabricate bolometers with Neutron Transmutation Doped (NTD) Ge thermistors that demonstrated high optical coupling (Church et al. 1996) and were developed for a ground-based millimeter-wave receiver (Mauskopf et al. 1997). The next generation of devices used In bump-bonded thermistors to achieve devices with performance product NEP*sqrt(tau) = 3e - 18 j at 300 mK, demonstrating a full order of magnitude improvement over pervious devices. These devices achieved an NEP = 1e-18 W/rtHz (Murray et al. 1996) as promised in the proposal. Sensitivities as good as 1e - 19 W/rtHz appear achievable with the silicon nitride architecture (Bock et al. 1997). Finally, arrays of micromesh bolometers were shown to be feasible in the last year of the program by etching a large number of devices on a single silicon wafer (75 mm). Full arrays were subsequently demonstrated for selection on the ESA/NASA Far-Infrared Space Telescope (FIRST) in competition with detectors provided by CEA in France and GSFC in the US Micromesh bolometer arrays are now baselined for both the ESA/NASA Planck and FIRST missions.

  2. Design of micro-sensor-array detector for toxic gas

    NASA Astrophysics Data System (ADS)

    Liao, Hai-yang; Tian, Peng

    2010-08-01

    To quickly measure the trace concentration of the single component toxic gas (e.g. sarin), a micro-array toxic gas detector is designed. A 3 x 3 gas sensor array with metalloporphyrins as sensitive materials is introduced. A micro-capsule that can be easy to be loaded and unloaded is designed for the gas reaction. A fiber-array optical path is designed, which is based on the principle that gas sensors will show different colors after reaction with the toxic gas. The tricolor information about the concentration of gas is collected by the color liner CCD. A control handling system with C8051F021 MCU as the core is implemented and embedded into the detector to perform the functions of gas sampling, data collection and analysis calculation. Data acquisition experimental results show that the proposed scheme can effectively collect the color information after gas reaction. Moreover, the system has many important advantages, such as small size, compact structure, high degree of automation, fast detection speed and high performance-cost ratio, etc.

  3. Novel Multiplexing Technique for Detector and Mixer Arrays

    NASA Technical Reports Server (NTRS)

    Karasik, Boris S.; McGrath, William R.

    2001-01-01

    Future submillimeter and far-infrared space telescopes will require large-format (many 1000's of elements) imaging detector arrays to perform state-of-the-art astronomical observations. A crucial issue related to a focal plane array is a readout scheme which is compatible with large numbers of cryogenically-cooled (typically < 1 K) detectors elements. When the number of elements becomes of the order of thousands, the physical layout for individual readout amplifiers becomes nearly impossible to realize for practical systems. Another important concern is the large number of wires leading to a 0.1-0.3 K platform. In the case of superconducting transition edge sensors (TES), a scheme for time-division multiplexing of SQUID read-out amplifiers has been recently demonstrated. In this scheme the number of SQUIDs is equal to the number (N) of the detectors, but only one SQUID is turned on at a time. The SQUIDs are connected in series in each column of the array, so the number of wires leading to the amplifiers can be reduced, but it is still of the order of N. Another approach uses a frequency domain multiplexing scheme of the bolometer array. The bolometers are biased with ac currents whose frequencies are individual for each element and are much higher than the bolometer bandwidth. The output signals are connected in series in a summing loop which is coupled to a single SQUID amplifier. The total number of channels depends on the ratio between the SQUID bandwidth and the bolometer bandwidth and can be at least 100 according to the authors. An important concern about this technique is a contribution of the out-of-band Johnson noise which multiplies by factor N(exp 1/2) for each frequency channel. We propose a novel solution for large format arrays based on the Hadamard transform coding technique which requires only one amplifier to read out the entire array of potentially many 1000's of elements and uses approximately 10 wires between the cold stage and room temperature

  4. Intra-pixel response of infrared detector arrays for JWST

    NASA Astrophysics Data System (ADS)

    Hardy, Tim; Baril, M. R.; Pazder, J.; Stilburn, J. S.

    2008-07-01

    The near-infrared instruments on the James Webb Space Telescope will use 5 micron cutoff HAWAII-2RG detector arrays. We have investigated the response of this type of detector at sub-pixel resolution to determine whether variations at this scale would affect the performance of the instruments. Using a simple experimental setup we were able to get measurements with a resolution of approximately 4 microns. We have measured an un-hybridized HAWAII-1RG multiplexer, a hybridized HAWAII-1RG device with a 5 micron cutoff HgCdTe detector layer, and a hybridized HAWAII-2RG device with a 5 micron cutoff substrate-removed HgCdTe detector layer. We found that the intra-pixel response functions of the hybrid devices are basically smooth and well behaved, and vary little from pixel to pixel. However, we did find numerous sub-pixel sized defects, notably some long straight thin features like scratches. We were not able to detect any significant variations with wavelength between 0.65 and 2.2 microns, but in the -1RG device there was a variation with temperature. When cooled from 80K to 40K, the pixel response became narrower, and some signal began to be lost at the edges of the pixel. We believe this reflects a reduction in charge diffusion at the lower temperature.

  5. Performance simulations of the medusa neutron detector array (abstract)

    SciTech Connect

    Kremens, R.L.; Russotto, M.A.; Tudman, S. )

    1995-01-01

    A 960-channel neutron detector array is under construction to measure various neutron reaction products from direct-drive laser-driven inertially confined fusion experiments. Analytical and Monte-Carlo model simulations have been completed which demonstrate the usefulness of this diagnostic for broad classes of fusion experiments. The modeling accounts for neutron production rate and spectra from the target and detector and acquisition electronics response. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460 and the University of Rochester. The support of DOE does not constitute an endorsement by DOE of the views expressed in this article.

  6. Undersampling Correction for Array Detector-Based Satellite Spectrometers

    NASA Technical Reports Server (NTRS)

    Chance, Kelly; Kurosu, Thomas P.; Sioris, Christopher E.

    2004-01-01

    Array detector-based instruments are now fundamental to measurements of ozone and other atmospheric trace gases from space in the ultraviolet, visible, and infrared. The present generation of such instruments suffers, to a greater or lesser degree, from undersampling of the spectra, leading to difficulties in the analysis of atmospheric radiances. We provide extended analysis of the undersampling suffered by modem satellite spectrometers, which include Global Ozone Monitoring Experiment (GOME), Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), Ozone Monitoring Instrument (OMI), and Ozone Mapping and Profiler Suite (OMPS). The analysis includes basic undersampling, the effects of binning into separate detector pixels, and the application of high-resolution Fraunhofer spectral data to correct for undersampling in many useful cases.

  7. Curved-channel microchannel array plates. [photoelectric detectors

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1981-01-01

    The microchannel array plate (MCP) is a photoelectric detector with an imaging capability comparable to that of a photographic plate. Recently MCPs in which the channels are curved to inhibit ion feedback have become available. These devices represent a major advance in MCP technology, since a single curved-channel MCP can be operated stably at high gain in the pulse-counting mode without any of the problems of stability of response or short lifetime reported for 'chevron' MCP detectors. Attention is given to the mode of operation of channel electron multipliers (CEM) and MCP, curved-channel MCP, test procedures, and performance characteristics. The accumulated test data show that the fundamental operating characteristics of the curved-channel MCP are directly related to those for the CEM.

  8. An MLC calibration method using a detector array

    SciTech Connect

    Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray

    2009-10-15

    Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw's leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf's position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 {+-}0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of {+-}0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration.

  9. Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry

    NASA Astrophysics Data System (ADS)

    Bock, James

    2014-01-01

    We are developing high-sensitivity millimeter-wave detector arrays for measuring the polarization of the cosmic microwave background (CMB). This development is directed to advance the technology readiness of the Inflation Probe mission in NASA's Physics of the Cosmos program. The Inflation Probe is a fourth-generation CMB satellite that will measure the polarization of the CMB to astrophysical limits, characterizing the inflationary polarization signal, mapping large-scale structure based on polarization induced by gravitational lensing, and mapping Galactic magnetic fields through measurements of polarized dust emission. The inflationary polarization signal is produced by a background of gravitational waves from the epoch of inflation, an exponential expansion of space-time in the early universe, with an amplitude that depends on the physical mechanism producing inflation. The inflationary polarization signal may be distinguished by its unique 'B-mode' vector properties from polarization from the density variations that predominantly source CMB temperature anisotropy. Mission concepts for the Inflation Probe are being developed in the US, Europe and Japan. The arrays are based on planar antennas that provide integral beam collimation, polarization analysis, and spectral band definition in a compact lithographed format that eliminates discrete fore-optics such as lenses and feedhorns. The antennas are coupled to transition-edge superconducting bolometers, read out with multiplexed SQUID current amplifiers. The superconducting sensors and readouts developed in this program share common technologies with NASA X-ray and FIR detector applications. Our program targets developments required for space observations, and we discuss our technical progress over the past two years and plans for future development. We are incorporating arrays into active sub-orbital and ground-based experiments, which advance technology readiness while producing state of the art CMB

  10. Capillary Array Waveguide Amplified Fluorescence Detector for mHealth

    PubMed Central

    Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

    2013-01-01

    array can potentially be used for sensitive analysis of multiple fluorescent detection assays simultaneously. The simple phone based capillary array approach presented in this paper is capable of amplifying weak fluorescent signals thereby improving the sensitivity of optical detectors based on mobile phones. This may allow sensitive biological assays to be measured with low sensitivity detectors and may make mHealth practical for many diagnostics applications, especially in resource-poor and global health settings. PMID:24039345

  11. Antenna coupled detectors for 2D staring focal plane arrays

    NASA Astrophysics Data System (ADS)

    Gritz, Michael A.; Kolasa, Borys; Lail, Brian; Burkholder, Robert; Chen, Leonard

    2013-06-01

    Millimeter-wave (mmW)/sub-mmW/THz region of the electro-magnetic spectrum enables imaging thru clothing and other obscurants such as fog, clouds, smoke, sand, and dust. Therefore considerable interest exists in developing low cost millimeter-wave imaging (MMWI) systems. Previous MMWI systems have evolved from crude mechanically scanned, single element receiver systems into very complex multiple receiver camera systems. Initial systems required many expensive mmW integrated-circuit low-noise amplifiers. In order to reduce the cost and complexity of the existing systems, attempts have been made to develop new mmW imaging sensors employing direct detection arrays. In this paper, we report on Raytheon's recent development of a unique focal plane array technology, which operates broadly from the mmW through the sub-mmW/THz region. Raytheon's innovative nano-antenna based detector enables low cost production of 2D staring mmW focal plane arrays (mmW FPA), which not only have equivalent sensitivity and performance to existing MMWI systems, but require no mechanical scanning.

  12. Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

    DOEpatents

    Strauss, Charlie E.

    1997-01-01

    Apparatus and method for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO.sub.2 laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart.

  13. Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

    DOEpatents

    Strauss, C.E.

    1997-11-18

    Apparatus and method are disclosed for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO{sub 2} laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart. 4 figs.

  14. Mechanical designs and development of TES bolometer detector arrays for the Advanced ACTPol experiment

    NASA Astrophysics Data System (ADS)

    Ward, Jonathan T.; Austermann, Jason; Beall, James A.; Choi, Steve K.; Crowley, Kevin T.; Devlin, Mark J.; Duff, Shannon M.; Gallardo, Patricio A.; Henderson, Shawn W.; Ho, Shuay-Pwu Patty; Hilton, Gene; Hubmayr, Johannes; Khavari, Niloufar; Klein, Jeffrey; Koopman, Brian J.; Li, Dale; McMahon, Jeffrey; Mumby, Grace; Nati, Federico; Niemack, Michael D.; Page, Lyman A.; Salatino, Maria; Schillaci, Alessandro; Schmitt, Benjamin L.; Simon, Sara M.; Staggs, Suzanne T.; Thornton, Robert; Ullom, Joel N.; Vavagiakis, Eve M.; Wollack, Edward J.

    2016-07-01

    The next generation Advanced ACTPol (AdvACT) experiment is currently underway and will consist of four Transition Edge Sensor (TES) bolometer arrays, with three operating together, totaling 5800 detectors on the sky. Building on experience gained with the ACTPol detector arrays, AdvACT will utilize various new technologies, including 150 mm detector wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors includes a feedhorn array of stacked silicon wafers which form a spline profile leading to each pixel. This is then followed by a waveguide interface plate, detector wafer, back short cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured from high purity copper and then gold plated. In addition to the detector array assembly, the array package also encloses cryogenic readout electronics. We present the full mechanical design of the AdvACT high frequency (HF) detector array package along with a detailed look at the detector array stack assemblies. This experiment will also make use of extensive hardware and software previously developed for ACT, which will be modified to incorporate the new AdvACT instruments. Therefore, we discuss the integration of all AdvACT arrays with pre-existing ACTPol infrastructure.

  15. Mechanical Design and Development of TES Bolometer Detector Arrays for the Advanced ACTPol Experiment

    NASA Technical Reports Server (NTRS)

    Ward, Jonathan T.; Austermann, Jason; Beall, James A.; Choi, Steve K.; Crowley, Kevin T.; Devlin, Mark J.; Duff, Shannon M.; Gallardo, Patricio M.; Henderson, Shawn W.; Ho, Shuay-Pwu Patty; Hilton, Gene; Hubmayr, Johannes; Khavari, Niloufar; Klein, Jeffrey; Koopman, Brian J.; Li, Dale; McMahon, Jeffrey; Mumby, Grace; Nati, Federico; Wollack, Edward J.

    2016-01-01

    The next generation Advanced ACTPol (AdvACT) experiment is currently underway and will consist of four Transition Edge Sensor (TES) bolometer arrays, with three operating together, totaling 5800 detectors on the sky. Building on experience gained with the ACTPol detector arrays, AdvACT will utilize various new technologies, including 150 mm detector wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors includes a feedhorn array of stacked silicon wafers which form a spline pro le leading to each pixel. This is then followed by a waveguide interface plate, detector wafer, back short cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured from high purity copper and then gold plated. In addition to the detector array assembly, the array package also encloses cryogenic readout electronics. We present the full mechanical design of the AdvACT high frequency (HF) detector array package along with a detailed look at the detector array stack assemblies. This experiment will also make use of extensive hardware and software previously developed for ACT, which will be modi ed to incorporate the new AdvACT instruments. Therefore, we discuss the integration of all AdvACT arrays with pre-existing ACTPol infrastructure.

  16. Thermal crosstalk simulation and measurement of linear terahertz detector arrays

    NASA Astrophysics Data System (ADS)

    Li, Weizhi; Huang, Zehua; Wang, Jun; Li, Mingyu; Gou, Jun; Jiang, Yadong

    2015-11-01

    Thermal simulation of differently structured linear terahertz detector arrays (TDAs) based on lithium tantalate was performed by finite element analysis (FEA). Simulation results revealed that a relatively simple TDA structure can have good thermal insulation, i.e., low thermal crosstalk effect (TCE), between adjacent pixels, which was thus selected for the real fabrication of TDA sample. Current responsivity (Ri) of the sample for a 2.52 THz source was measured to be 6.66 × 10-6 A/W and non-uniformity (NU) of Ri was 4.1%, showing good performance of the sample. TCE test result demonstrated that small TCE existed in the sample, which was in good agreement with the simulation results.

  17. Electrical breakdown gas detector featuring carbon nanotube array electrodes.

    PubMed

    Kim, Seongyul; Pal, Sunil; Ajayan, Pulickel M; Borca-Tasciuc, Theodorian; Koratkar, Nikhil

    2008-01-01

    We demonstrate here detection of dichloro-difluoro-methane and oxygen in mixtures with helium using a carbon nanotube electrical breakdown sensor device. The sensor is comprised of an aligned array of multiwalled carbon nanotubes deposited on a nickel based super-alloy (Inconel 600) as the anode; the counter electrode is a planar nickel sheet. By monitoring the electrical breakdown characteristics of oxygen and dichloro-difluoro-methane in a background of helium, we find that the detection limit for dichloro-difluoro-methane is approximately 0.1% and the corresponding limit for oxygen is approximately 1%. A phenomenologigal model is proposed to describe the trends observed in detection of the two mixtures. These results indicate that carbon nanotube based electrical breakdown sensors show potential as end detectors in gas-chromatography devices.

  18. Method of fabricating multiwavelength infrared focal plane array detector

    NASA Technical Reports Server (NTRS)

    Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)

    1996-01-01

    A multiwavelength local plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y.ltoreq.1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.

  19. Terahertz spectroscopy with a holographic Fourier transform spectrometer plus array detector using coherent synchrotron radiation

    SciTech Connect

    Nikolay I. Agladz, John Klopf, Gwyn Williams, Albert J. Sievers

    2010-06-01

    By use of coherent terahertz synchrotron radiation, we experimentally tested a holographic Fourier transform spectrometer coupled to an array detector to determine its viability as a spectral device. Somewhat surprisingly, the overall performance strongly depends on the absorptivity of the birefringent lithium tantalate pixels in the array detector.

  20. Energy spectrum measured by the telescope array surface detector

    NASA Astrophysics Data System (ADS)

    Ivanov, Dmitri

    2012-05-01

    Two conflicting measurements of the ultra high energy cosmic ray (UHECR) flux have been reported by the Akeno Giant Air Shower Array (AGASA) and the High Resolution Fly's Eye (HiRes) experiments. HiRes observes a ˜5sigma suppression at E = 1019.75 eV, which is in agreement with the prediction of Greisen-Zatsepin-Kuz'min (GZK) theory. AGASA, in contrast, sees the flux extended well beyond E = 1020 eV with no visible break, suggesting that the flux is limited only by the rate at which the sources can produce the UHECR and not by interaction of energetic particles with the cosmic microwave background, thus challenging the relativistic invariance principle. In response to this discrepancy, a new experiment named the Telescope Array (TA) has been deployed, which combines the detection elements used separately by HiRes and AGASA. We describe the TA surface detector (SD) analysis using a technique new to the field, which consists of a detailed Monte-Carlo (MC) simulation of the SD response to the natural cosmic rays, validating the MC by comparing its distributions with the data, and calculation of the SD aperture from the MC. We will also describe our reconstruction procedure, based solely upon the data, and its application to both data and the MC. Finally, we will describe the energy spectrum resulting from this analysis, which is found to be in excellent agreement with the HiRes result, and as such, is the first confirmation of the GZK effect by a ground array of scintillation counters.

  1. Assessment study of infrared detector arrays for low-background astronomical research

    NASA Technical Reports Server (NTRS)

    Ando, K. J.

    1978-01-01

    The current state-of-the-art of infrared detector arrays employing charge coupled devices (CCD) or charge injection devices (CID) readout are assessed. The applicability, limitations and potentials of such arrays under the low-background astronomical observing conditions of interest for SIRFT (Shuttle Infrared Telescope Facility) are determined. The following are reviewed: (1) monolithic extrinsic arrays; (2) monolithic intrinsic arrays; (3) charge injection devices; and (4) hybrid arrays.

  2. Demonstration of a passive, low-noise, millimeter-wave detector array for imaging

    NASA Astrophysics Data System (ADS)

    Wikner, David; Grossman, Erich

    2009-05-01

    The design of a millimeter-wave (MMW) camera is presented. The camera is meant to serve as a demonstration platform for a new 32-channel MMW detector array that requires no pre-amplification prior to detection. The Army Research Laboratory (ARL) and National Institute of Standards and Technology (NIST) have worked with the Defense Advanced Research Projects Agency and several contractors for four years to develop an affordable MMW detector array technology suitable for use in a large staring array. The camera described uses one particular embodiment of detector array that resulted from the program. This paper reviews the design of the MMW optics that will be used to form imagery with the linear array and the tradeoffs made in that design. Also presented are the results of laboratory tests of the detector array that were made at both ARL and NIST.

  3. Progress of Multicolor Single Detector to Detector Array Development for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Abedin, M. Nurul; Refaat, Tamer F.; Bhat, Ishwara; Xiao, Ye-Gao; Bandra, Sumith; Gunapala, Sarath D.

    2004-01-01

    Knowledge of the spatial and temporal distribution of atmospheric species such as CO2, O3, H2O, and CH4 is important for understanding the chemistry and physical cycles involving Earth s atmosphere. Although several remote sensing techniques are suitable for such measurements they are considered high cost techniques involving complicated instrumentation. Therefore, simultaneous measurement of atmospheric species using a single remote sensing instrument is significant for minimizing cost, size and complexity. While maintaining the instrument sensitivity and range, quality of multicolor detector, in terms of high quantum efficiency and low noise are vital for these missions. As the first step for developing multicolor focal plan array, the structure of a single element multicolor detector is presented in this paper. The detector consists of three p-n junction layers of Si, GaSb and InAs wafer bonded to cover the spectral range UV to 900 nm, 800 nm to 1.7 m, and 1.5 m to 3.4 m, respectively. Modeling of the absorption coefficient for each material was carried out for optimizing the layers thicknesses for maximum absorption. The resulted quantum efficiency of each layer has been determined except InAs layer. The optical and electrical characterization of each layer structure is reported including dark current and spectral response measurements of Si pin structure and of GaSb and InAs p-n junctions. The effect of the material processing is discussed.

  4. Stressed and unstressed Ge:Ga detector arrays for airborne astronomy

    NASA Technical Reports Server (NTRS)

    Stacey, G. J.; Beeman, J. W.; Haller, E. E.; Geis, N.; Poglitsch, A.; Rumitz, M.

    1992-01-01

    The construction and operation of 2D arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-IR astronomy from the Kuiper Airborne Observatory is presented. The 25 element (5 x 5) arrays are designed for a new cryogenically cooled spectrometer. The 2D spatial array described has the advantage of absolute registry between pixels in a map.

  5. The CSI Schools Project

    ERIC Educational Resources Information Center

    Dorling, Mark; Johnstone, Emm

    2012-01-01

    The popularity of forensic science in schools continues to grow alongside the proportion of prime time scheduling devoted to CSI television shows. Yet the understanding of how forensic tests are used in narrowing down a field of possible suspects to the point where just one can be arrested or taken to trial is far less well understood. Students…

  6. 13 micron cutoff HgCdTe detector arrays for space and ground-based astronomy

    NASA Astrophysics Data System (ADS)

    McMurtry, Craig W.; Cabrera, Mario S.; Dorn, Meghan L.; Pipher, Judith L.; Forrest, William J.

    2016-07-01

    With the recent success of our development of 10 micron HgCdTe infrared (IR) detector arrays,1,2 we have used what we learned and extended the cutoff wavelength to 13 microns. These 13 micron HgCdTe detector arrays can operate at higher temperatures than Si:As, e.g. in a properly designed spacecraft with passive cooling, the 13 micron IR array will work well at temperatures around 30K. We present the initial measurements of dark current, noise and quantum efficiency for the first deliveries of 13 micron HgCdTe detector arrays from Teledyne Imaging Sensors. We also discuss our plans to develop 15 micron cutoff HgCdTe detector arrays which would facilitate the detection of the broad CO2 absorption feature in the atmospheres of exoplanets, particularly those in the habitable zone of their host star.

  7. The development and test of ultra-large-format multi-anode microchannel array detector systems

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1984-01-01

    The specific tasks that were accomplished with each of the key elements of the multi-anode microchannel array detector system are described. The modes of operation of position-sensitive electronic readout systems for use with high-gain microchannel plates are described and their performance characteristics compared and contrasted. Multi-anode microchannel array detector systems with formats as large as 256 x 1024 pixels are currently under evaluation. Preliminary performance data for sealed ultraviolet and visible-light detector tubes show that the detector systems have unique characteristics which make them complementary to photoconductive array detectors, such as CCDs, and superior to alternative pulse-counting detector systems employing high-gain MCPs.

  8. Synthesis arrangement and parity correction of linear array infrared detector

    NASA Astrophysics Data System (ADS)

    Wang, Qun; Hong, Pu; Wang, Bo; Wang, Chensheng

    2010-11-01

    According to the configuration and technical specification of the detector, which has multiple channels, channels mixing, high speed outputs and separate columns between odd and even, a real time digital processing unit based on the CPLD, FPGA and DSP has been developed to achieve the data synthesis and arrangement function and the parity correction algorithm. A special interface circuit with 4 CPLDs is designed to complete the first synthesis step where the 16 channels of data are combined into 4 channels. The second step is finished in FPGA and ROM address encoder where the 4 channels of data are combined into 1 channel. For output data synchronization, FIFO is adopted to achieve the delay of even channels in the parity correction. Data of odd channels enters the columns synthesis unit without any processing and even channels shall be processed in the columns synthesis unit after entering the FIFO unit first and experiencing the delay process. Thereby the pre-processing before image processing of the linear array thermal imager is accomplished.

  9. Design data brochure for CSI series V solar heating system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Generalized information on system configuration, system sizing, and mechanical layout is presented to assist the architect or designer in preparing construction drawings and specifications for the installation of the CSI integrated solar heating systems. Efficiency in space utilization of a full length collector and the importance of proper sizing of the collector array are among the topics discussed. Details of storage and transport subsystems are provided along with drawings and specifications of all components of the CSI system.

  10. Method of fabricating a PbS-PbSe IR detector array

    NASA Technical Reports Server (NTRS)

    Barrett, John R. (Inventor)

    1987-01-01

    A silicon wafer is provided which does not employ individually bonded leads between the IR sensitive elements and the input stages of multiplexers. The wafer is first coated with lead selenide in a first detector array area and is thereafter coated with lead sulfide within a second detector array area. The described steps result in the direct chemical deposition of lead selenide and lead sulfide upon the silicon wafer to eliminate individual wire bonding, bumping, flip chiping, planar interconnecting methods of connecting detector array elements to silicon chip circuitry, e.g., multiplexers, to enable easy fabrication of very long arrays. The electrode structure employed, produces an increase in the electrical field gradient between the electrodes for a given volume of detector material, relative to conventional electrode configurations.

  11. Method for producing a hybridization of detector array and integrated circuit for readout

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Grunthaner, Frank J. (Inventor)

    1993-01-01

    A process is explained for fabricating a detector array in a layer of semiconductor material on one substrate and an integrated readout circuit in a layer of semiconductor material on a separate substrate in order to select semiconductor material for optimum performance of each structure, such as GaAs for the detector array and Si for the integrated readout circuit. The detector array layer is lifted off its substrate, laminated on the metallized surface on the integrated surface, etched with reticulating channels to the surface of the integrated circuit, and provided with interconnections between the detector array pixels and the integrated readout circuit through the channels. The adhesive material for the lamination is selected to be chemically stable to provide electrical and thermal insulation and to provide stress release between the two structures fabricated in semiconductor materials that may have different coefficients of thermal expansion.

  12. Assembly and Integration Process of the First High Density Detector Array for the Atacama Cosmology Telescope

    NASA Technical Reports Server (NTRS)

    Li, Yaqiong; Choi, Steve; Ho, Shuay-Pwu; Crowley, Kevin T.; Salatino, Maria; Simon, Sara M.; Staggs, Suzanne T.; Nati, Federico; Wollack, Edward J.

    2016-01-01

    The Advanced ACTPol (AdvACT) upgrade on the Atacama Cosmology Telescope (ACT) consists of multichroicTransition Edge Sensor (TES) detector arrays to measure the Cosmic Microwave Background (CMB) polarization anisotropies in multiple frequency bands. The first AdvACT detector array, sensitive to both 150 and 230 GHz, is fabricated on a 150 mm diameter wafer and read out with a completely different scheme compared to ACTPol. Approximately 2000 TES bolometers are packed into the wafer leading to both a much denser detector density and readout circuitry. The demonstration of the assembly and integration of the AdvACT arrays is important for the next generation CMB experiments, which will continue to increase the pixel number and density. We present the detailed assembly process of the first AdvACT detector array.

  13. Underground Prototype Water Cherenkov Muon Detector with the Tibet Air Shower Array

    SciTech Connect

    Amenomori, M.; Nanjo, H.; Bi, X. J.; Ding, L. K.; Feng, Zhaoyang; He, H. H.; Hu, H. B.; Lu, H.; Lu, S. L.; Ren, J. R.; Tan, Y. H.; Wang, B.; Wang, H.; Wang, Y.; Wu, H. R.; Zhang, H. M.; Zhang, J. L.; Zhang, Y.; Chen, D.; Kawata, K.

    2008-12-24

    We are planning to build a 10,000 m{sup 2} water-Cherenkov-type muon detector (MD) array under the Tibet air shower (AS) array. The Tibet AS+MD array will have the sensitivity to detect gamma rays in the 100 TeV region by an order of the magnitude better than any other previous existing detectors in the world. In the late fall of 2007, a prototype water Cherenkov muon detector of approximately 100 m{sup 2} was constructed under the existing Tibet AS array. The preliminary data analysis is in good agreement with our MC simulation. We are now ready for further expanding the underground water Cherenkov muon detector.

  14. Assembly and integration process of the first high density detector array for the Atacama Cosmology Telescope

    NASA Astrophysics Data System (ADS)

    Li, Yaqiong; Choi, Steve; Ho, Shuay-Pwu; Crowley, Kevin T.; Salatino, Maria; Simon, Sara M.; Staggs, Suzanne T.; Nati, Federico; Ward, Jonathan; Schmitt, Benjamin L.; Henderson, Shawn; Koopman, Brian J.; Gallardo, Patricio A.; Vavagiakis, Eve M.; Niemack, Michael D.; McMahon, Jeff; Duff, Shannon M.; Schillaci, Alessandro; Hubmayr, Johannes; Hilton, Gene C.; Beall, James A.; Wollack, Edward J.

    2016-07-01

    The Advanced ACTPol (AdvACT) upgrade on the Atacama Cosmology Telescope (ACT) consists of multichroic Transition Edge Sensor (TES) detector arrays to measure the Cosmic Microwave Background (CMB) polarization anisotropies in multiple frequency bands. The first AdvACT detector array, sensitive to both 150 and 230 GHz, is fabricated on a 150 mm diameter wafer and read out with a completely different scheme compared to ACTPol. Approximately 2000 TES bolometers are packed into the wafer leading to both a much denser detector density and readout circuitry. The demonstration of the assembly and integration of the AdvACT arrays is important for the next generation CMB experiments, which will continue to increase the pixel number and density. We present the detailed assembly process of the first AdvACT detector array.

  15. Characteristics of stereo images from detectors in focal plane array.

    PubMed

    Son, Jung-Young; Yeom, Seokwon; Chun, Joo-Hwan; Guschin, Vladmir P; Lee, Dong-Su

    2011-07-01

    The equivalent ray geometry of two horizontally aligned detectors at the focal plane of the main antenna in a millimeter wave imaging system is analyzed to reveal the reason why the images from the detectors are fused as an image with a depth sense. Scanning the main antenna in both horizontal and vertical directions makes each detector perform as a camera, and the two detectors can work like a stereo camera in the millimeter wave range. However, the stereo camera geometry is different from that of the stereo camera used in the visual spectral range because the detectors' viewing directions are diverging to each other and they are a certain distance apart. The depth sense is mainly induced by the distance between detectors. The images obtained from the detectors in the millimeter imaging system are perceived with a good depth sense. The disparities responsible for the depth sense are identified in the images.

  16. Enhancement of concentration range of chromatographically detectable components with array detector mass spectrometry

    SciTech Connect

    Enke, Christie

    2013-02-19

    Methods and instruments for high dynamic range analysis of sample components are described. A sample is subjected to time-dependent separation, ionized, and the ions dispersed with a constant integration time across an array of detectors according to the ions m/z values. Each of the detectors in the array has a dynamically adjustable gain or a logarithmic response function, producing an instrument capable of detecting a ratio of responses or 4 or more orders of magnitude.

  17. Chemical imaging of cotton fibers using an infrared microscope and a focal-plane array detector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this presentation, the chemical imaging of cotton fibers with an infrared microscope and a Focal-Plane Array (FPA) detector will be discussed. Infrared spectroscopy can provide us with information on the structure and quality of cotton fibers. In addition, FPA detectors allow for simultaneous spe...

  18. Brief Introduction to the γ-DETECTOR Array at Institute of Modern Physics in Lanzhou

    NASA Astrophysics Data System (ADS)

    Hua, W.; Zhang, N. T.; Liu, M. L.; Zheng, Y.; Fang, Y. D.; Zhou, X. H.; Zhang, Y. H.; Lei, X. G.; Guo, Y. X.

    2013-11-01

    A new γ-detector array at Institute of modern physics in Lanzhou is now in construction. The spherical frame is designed using Solidworks, and is assembled by 4 kinds of irregular polygons. 32 detectors could be placed on this frame in maximum, which are arranged with 4-4-4-8-4-4-4 configuration.

  19. Vacuum photodiode detector array for broadband UV detection in a tokamak plasma.

    PubMed

    Zweben, S J; Menyuk, C R; Taylor, R J

    1979-08-01

    An array of vacuum photodiode detectors has been used to monitor discharge equilibrium, stability, and cleanliness in the Macrotor tokamak. These detectors use the photoelectric effect on small tungsten plates to measure UV emission in the band lambda approximately 200-1200 angstroms, and so are sensitive mainly to impurity line radiation in Macrotor. The response of this system to controlled impurity contamination experiments and to disruptions is described. The design, construction, and background problems associated with these detectors are discussed in detail.

  20. Modulation Transfer Function (MTF) measurement techniques for lenses and linear detector arrays

    NASA Technical Reports Server (NTRS)

    Schnabel, J. J., Jr.; Kaishoven, J. E., Jr.; Tom, D.

    1984-01-01

    Application is the determination of the Modulation Transfer Function (MTF) for linear detector arrays. A system set up requires knowledge of the MTF of the imaging lens. Procedure for this measurement is described for standard optical lab equipment. Given this information, various possible approaches to MTF measurement for linear arrays is described. The knife edge method is then described in detail.

  1. A near-infrared 64-pixel superconducting nanowire single photon detector array with integrated multiplexed readout

    SciTech Connect

    Allman, M. S. Verma, V. B.; Stevens, M.; Gerrits, T.; Horansky, R. D.; Lita, A. E.; Mirin, R.; Nam, S. W.; Marsili, F.; Beyer, A.; Shaw, M. D.; Kumor, D.

    2015-05-11

    We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array as well as characterization measurements are discussed.

  2. Application of the Monte Carlo method for the efficiency calibration of CsI and NaI detectors for gamma-ray measurements from terrestrial samples.

    PubMed

    Baccouche, S; Al-Azmi, D; Karunakara, N; Trabelsi, A

    2012-01-01

    Gamma-ray measurements in terrestrial/environmental samples require the use of high efficient detectors because of the low level of the radionuclide activity concentrations in the samples; thus scintillators are suitable for this purpose. Two scintillation detectors were studied in this work; CsI(Tl) and NaI(Tl) with identical size for measurement of terrestrial samples for performance study. This work describes a Monte Carlo method for making the full-energy efficiency calibration curves for both detectors using gamma-ray energies associated with the decay of naturally occurring radionuclides (137)Cs (661keV), (40)K (1460keV), (238)U ((214)Bi, 1764keV) and (232)Th ((208)Tl, 2614keV), which are found in terrestrial samples. The magnitude of the coincidence summing effect occurring for the 2614keV emission of (208)Tl is assessed by simulation. The method provides an efficient tool to make the full-energy efficiency calibration curve for scintillation detectors for any samples geometry and volume in order to determine accurate activity concentrations in terrestrial samples.

  3. Detector arrays for high resolution spectroscopy from 5-28 microns (Contributed)

    NASA Astrophysics Data System (ADS)

    Wiedemann, G.; Jennings, D. E.; Moseley, S. H.; Lamb, G.

    A linear Si:As BIB detector array (Rockwell International) is being implemented in a postdispersion detection system for ground based Fourier transform spectrometers. The array version can be used as a multichannel narrow band filter for extended spectral coverage or for imaging with a narrow bandpass. A Si:As solid state photomultiplier array (Rockwell) is evaluated for use in high resolution infrared spectrometers. Test results and applications are discussed.

  4. Integrated filter and detector array for spectral imaging

    NASA Technical Reports Server (NTRS)

    Labaw, Clayton C. (Inventor)

    1992-01-01

    A spectral imaging system having an integrated filter and photodetector array is disclosed. The filter has narrow transmission bands which vary in frequency along the photodetector array. The frequency variation of the transmission bands is matched to, and aligned with, the frequency variation of a received spectral image. The filter is deposited directly on the photodetector array by a low temperature deposition process. By depositing the filter directly on the photodetector array, permanent alignment is achieved for all temperatures, spectral crosstalk is substantially eliminated, and a high signal to noise ratio is achieved.

  5. Electronics for the Extensive Air Shower Detector Array at the University of Puebla

    NASA Astrophysics Data System (ADS)

    Pérez, E.; Conde, R.; Martínez, O.; Murrieta, T.; Salazar, H.; Villaseñor, L.

    2006-09-01

    In this paper we describe in detail the electronics cards that were designed to be the basis of the data acquisition system (DAS) of the extensive air shower detector array built in the Campus of the University of Puebla. The purpose of this observatory is to measure the energy and arrival direction of primary cosmic rays with energies around 1015 eV. The array consists of 18 liquid scintillator detectors (12 in the first stage) and 6 water Cherenkov detectors (one of 10 m2 cross section and five smaller ones of 1.86 m2 cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m2. The electronics described here uses analog to digital converters of 10 bits working at a sampling speed of 40 MS/s and field-programmable gate array (FPGA).

  6. Trigger and aperture of the surface detector array of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Abraham, J.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arisaka, K.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avila, G.; Bäcker, T.; Badagnani, D.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Barroso, S. L. C.; Baughman, B.; Bauleo, P.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; Benzvi, S.; Berat, C.; Bergmann, T.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Colombo, E.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Domenico, M.; de Donato, C.; de Jong, S. J.; de La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; de Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; Del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Duvernois, M. A.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrero, A.; Fick, B.; Filevich, A.; Filipčič, A.; Fleck, I.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fulgione, W.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Goggin, L. M.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hague, J. D.; Halenka, V.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Hussain, M.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Jiraskova, S.; Kadija, K.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D.-H.; Krieger, A.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, K.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Lee, J.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McEwen, M.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Meurer, C.; Mičanović, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Mueller, S.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parlati, S.; Parra, A.; Parrisius, J.; Parsons, R. D.; Pastor, S.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; PeĶala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Redondo, A.; Revenu, B.; Rezende, F. A. S.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivière, C.; Rizi, V.; Robledo, C.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-D'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santo, E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schroeder, F.; Schulte, S.; Schüssler, F.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; Sigl, G.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Stasielak, J.; Stephan, M.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Tamashiro, A.; Tamburro, A.; Tapia, A.; Tarutina, T.; Taşcău, O.; Tcaciuc, R.; Tcherniakhovski, D.; Tegolo, D.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Venters, T.; Verzi, V.; Videla, M.; Villaseñor, L.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Watson, A. A.; Westerhoff, S.; Whelan, B. J.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Williams, C.; Winchen, T.; Winnick, M. G.; Wundheiler, B.; Yamamoto, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.

    2010-01-01

    The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3×1018eV, for all zenith angles between 0∘ and 60∘, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance.

  7. Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays.

    PubMed

    Szkudlarek, Krzesimir; Sypek, Maciej; Cywiński, Grzegorz; Suszek, Jarosław; Zagrajek, Przemysław; Feduniewicz-Żmuda, Anna; Yahniuk, Ivan; Yatsunenko, Sergey; Nowakowska-Siwińska, Anna; Coquillat, Dominique; But, Dmytro B; Rachoń, Martyna; Węgrzyńska, Karolina; Skierbiszewski, Czesław; Knap, Wojciech

    2016-09-05

    We present the concept, the fabrication processes and the experimental results for materials and optics that can be used for terahertz field-effect transistor detector focal plane arrays. More specifically, we propose 3D printed arrays of a new type - diffractive multi-zone lenses of which the performance is superior to that of previously used mono-zone diffractive or refractive elements and evaluate them with GaN/AlGaN field-effect transistor terahertz detectors. Experiments performed in the 300-GHz atmospheric window show that the lens arrays offer both a good efficiency and good uniformity, and may improve the signal-to-noise ratio of the terahertz field-effect transistor detectors by more than one order of magnitude. In practice, we tested 3 × 12 lens linear arrays with printed circuit board THz detector arrays used in postal security scanners and observed significant signal-to-noise improvements. Our results clearly show that the proposed technology provides a way to produce cost-effective, reproducible, flat optics for large-size field-effect transistor THz-detector focal plane arrays.

  8. Terahertz detectors arrays based on orderly aligned InN nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Xuechen; Liu, Huiqiang; Li, Qiuguo; Chen, Hao; Peng, Rufang; Chu, Sheng; Cheng, Binbin

    2015-08-01

    Nanostructured terahertz detectors employing a single semiconducting nanowire or graphene sheet have recently generated considerable interest as an alternative to existing THz technologies, for their merit on the ease of fabrication and above-room-temperature operation. However, the lack of alignment in nanostructure device hindered their potential toward practical applications. The present work reports ordered terahertz detectors arrays based on neatly aligned InN nanowires. The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a “transfer-printing” method. Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose. The detector showed good photoresponse as well as low noise level. Besides, dense arrays of such detectors were also fabricated, which rendered a peak responsivity of 1.1 V/W from 7 detectors connected in series.

  9. Terahertz detectors arrays based on orderly aligned InN nanowires

    PubMed Central

    Chen, Xuechen; Liu, Huiqiang; Li, Qiuguo; Chen, Hao; Peng, Rufang; Chu, Sheng; Cheng, Binbin

    2015-01-01

    Nanostructured terahertz detectors employing a single semiconducting nanowire or graphene sheet have recently generated considerable interest as an alternative to existing THz technologies, for their merit on the ease of fabrication and above-room-temperature operation. However, the lack of alignment in nanostructure device hindered their potential toward practical applications. The present work reports ordered terahertz detectors arrays based on neatly aligned InN nanowires. The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a “transfer-printing” method. Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose. The detector showed good photoresponse as well as low noise level. Besides, dense arrays of such detectors were also fabricated, which rendered a peak responsivity of 1.1 V/W from 7 detectors connected in series. PMID:26289498

  10. Some energy considerations in gamma ray burst location determinations by an anisotropic array of detectors

    NASA Technical Reports Server (NTRS)

    Young, J. H.

    1986-01-01

    The anisotropic array of detectors to be used in the Burst and Transient Experiment (BATSE) for locating gamma ray burst sources is examined with respect to its ability to locate those sources by means of the relative response of its eight detectors. It was shown that the energy-dependent attenuation effects of the aluminum window covering each detector has a significant effect on source location determinations. Location formulas were derived as a function of detector counts and gamma ray energies in the range 50 to 150 keV. Deviation formulas were derived and serve to indicate the location error that would be cuased by ignoring the influence of the passive absorber.

  11. Quantum Well and Quantum Dot Modeling for Advanced Infrared Detectors and Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Ting, David; Gunapala, S. D.; Bandara, S. V.; Hill, C. J.

    2006-01-01

    This viewgraph presentation reviews the modeling of Quantum Well Infrared Detectors (QWIP) and Quantum Dot Infrared Detectors (QDIP) in the development of Focal Plane Arrays (FPA). The QWIP Detector being developed is a dual band detector. It is capable of running on two bands Long-Wave Infrared (LWIR) and Medium Wavelength Infrared (MWIR). The same large-format dual-band FPA technology can be applied to Quantum Dot Infrared Photodetector (QDIP) with no modification, once QDIP exceeds QWIP in single device performance. Details of the devices are reviewed.

  12. Non-volatile resistive photo-switches for flexible image detector arrays

    NASA Astrophysics Data System (ADS)

    Nau, Sebastian; Wolf, Christoph; Sax, Stefan; List-Kratochvil, Emil J. W.

    2015-09-01

    The increasing quest to find lightweight, conformable or flexible image detectors for machine vision or medical imaging brings organic electronics into the spotlight for these fields of application. Here were we introduce a unique imaging device concept and its utilization in an organic, flexible detector array with simple passive matrix wiring. We present a flexible organic image detector array built up from non-volatile resistive multi-bit photo-switchable elements. This unique realization is based on an organic photodiode combined with an organic resistive memory device wired in a simple crossbar configuration. The presented concept exhibits significant advantages compared to present organic and inorganic detector array technologies, facilitating the detection and simultaneous storage of the image information in one detector pixel, yet also allowing for simple read-out of the information from a simple passive-matrix crossbar wiring. This concept is demonstrated for single photo-switchable pixels as well as for arrays with sizes up to 32 by 32 pixels (1024 bit). The presented results pave the way for a versatile flexible and easy-to-fabricate sensor array technology. In a final step, the concept was expanded to detection of x-rays.

  13. Assembly, characterization, and operation of large-scale TES detector arrays for ACTPol

    NASA Astrophysics Data System (ADS)

    Pappas, Christine Goodwin

    2016-01-01

    The Polarization-sensitive Receiver for the Atacama Cosmology Telescope (ACTPol) is designed to measure the Cosmic Microwave Background (CMB) temperature and polarization anisotropies on small angular scales. Measurements of the CMB temperature and polarization anisotropies have produced arguably the most important cosmological data to date, establishing the LambdaCDM model and providing the best constraints on most of its parameters. To detect the very small fluctuations in the CMB signal across the sky, ACTPol uses feedhorn-coupled Transition-Edge Sensor (TES) detectors. A TES is a superconducting thin film operated in the transition region between the superconducting and normal states, where it functions as a highly sensitive resistive thermometer. In this thesis, aspects of the assembly, characterization, and in-field operation of the ACTPol TES detector arrays are discussed. First, a novel microfabrication process for producing high-density superconducting aluminum/polyimide flexible circuitry (flex) designed to connect large-scale detector arrays to the first stage of readout is presented. The flex is used in parts of the third ACTPol array and is currently being produced for use in the AdvACT detector arrays, which will begin to replace the ACTPol arrays in 2016. Next, we describe methods and results for the in-lab and on-telescope characterization of the detectors in the third ACTPol array. Finally, we describe the ACTPol TES R(T,I) transition shapes and how they affect the detector calibration and operation. Methods for measuring the exact detector calibration and re-biasing functions, taking into account the R(T,I) transition shape, are presented.

  14. Waveguide biosensor with integrated detector array for tuberculosis testing

    NASA Astrophysics Data System (ADS)

    Yan, Rongjin; Lynn, N. Scott; Kingry, Luke C.; Yi, Zhangjing; Slayden, Richard A.; Dandy, David S.; Lear, Kevin L.

    2011-01-01

    A label-free immunoassay using a local evanescent array coupled (LEAC) biosensor is reported. Complementary metal oxide semiconductor chips with integrated photoconductor arrays are used to detect an antibody to a M. tuberculosis protein antigen, HspX. The metrology limits of the LEAC sensor using dc and ac measurement systems correspond to average film thicknesses of 28 and 14 pm, respectively. Limits of detection are 87 and 108 pm, respectively, for mouse immunoglobulin G antibody patterning and antigen detection.

  15. Coherent summation of spatially distorted Doppler lidar signals using a two-dimensional heterodyne detector array

    NASA Technical Reports Server (NTRS)

    Chan, Kin Pui; Killinger, Dennis K.

    1992-01-01

    We have investigated the improvement in the signal-to-noise ratio for a coherent Doppler lidar through the use of a multi-element heterodyne detector array. Such an array enables the spatial summation of atmospheric refractive turbulence induced speckles, and time varying target speckles. Our recent experiments have shown that the non-coherent summation of the lidar signals from a heterodyne detector array can enhance the heterodyne mixing efficiency and thus the signal-to-noise ratio. In this paper, we expand this work to include the coherent summation of array signals. The digitized heterodyne signals were stored in a personal computer. Fast Fourier transforms were performed on both the non-coherent and coherent summations of the detector array signals. It was found that the coherent summation greatly enhanced the accuracy in the Doppler frequency estimate. A theoretical analysis was performed and indicated good agreement with experimental results. We have also applied these results to the more general lidar applications including atmospheric wind sensing, and have found that in most lidar applications the Doppler frequency estimate is increased through the use of the heterodyne detector array.

  16. A 16-channel avalanche photodiode detector array for visible and near-infrared flow cytometry

    NASA Astrophysics Data System (ADS)

    Lawrence, William G.; Stapels, Christopher; Farrell, Richard; Tario, Joseph D., Jr.; Podniesinski, Edward; Wallace, Paul K.; Christian, James F.

    2006-02-01

    We report on the development and application of a flow cytometer using a 16-channel avalanche photodiode (APD) linear detector array. The array is configured with a dispersive grating to simultaneously record emission over a broad wavelength range using the 16 APD channels of the linear APD array. The APD detector elements have a peak quantum efficiency of 80% near 900 nm and have at least 40% quantum efficiency over the 400-nm to 1000-nm wavelength range. The extended red sensitivity of the detector array facilitates the use of lower energy excitation sources and near IR emitting dyes which reduces the impact of autofluorescence in signal starved measurements. The wide wavelength sensitivity of the APD array permits the use of multiple excitation sources and many different fluorescent labels to maximize the number of independent parameters in a given experiment. We show the sensitivity and linearity measurements for a single APD detector. Initial results for the flow cytometer with the 16-element APD array and the 16-channel readout ASIC (application specific integrated circuit) are presented.

  17. Performance of high resolution decoding with Multi-Anode Microchannel Array detectors

    NASA Technical Reports Server (NTRS)

    Kasle, David B.; Horch, Elliott P.

    1993-01-01

    The Multi-Anode Microchannel Array (MAMA) is a microchannel plate based photon counting detector with applications in ground-based and space-based astronomy. The detector electronics decode the position of each photon event, and the decoding algorithm that associates a given event with the appropriate pixel is determined by the geometry of the anode array. The standard MAMA detector has a spatial resolution set by the anode array of 25 microns, but the MCP pore resolution exceeds this. The performance of a new algorithm that halves the pixel spacing and improves the pixel spatial resolution is described. The new algorithm does not degrade the pulse-pair resolution of the detector and does not require any modifications to the detector tube. Measurements of the detector's response demonstrate that high resolution decoding yields a 60 percent enhancement in spatial resolution. Measurements of the performance of the high resolution algorithm with a 14 micron MAMA detector are also described. The parameters that control high resolution performance are discussed. Results of the application of high resolution decoding to speckle interferometry are presented.

  18. Development of a mercuric iodide detector array for in-vivo x-ray imaging

    SciTech Connect

    Patt, B.E.; Iwanczyk, J.S.; Tornai, M.P.; Levin, C.S.; Hoffman, E.J.

    1995-12-31

    A nineteen element mercuric iodide (HgI{sub 2}) detector array has been developed in order to investigate the potential of using this technology for in-vivo x-ray and gamma-ray imaging. A prototype cross-grid detector array was constructed with hexagonal pixels of 1.9 mm diameter (active area = 3.28 mm{sup 2}) and 0.2 mm thick septa. The overall detector active area is roughly 65 mm{sup 2}. A detector thickness of 1.2 mm was used to achieve about 100% efficiency at 60 keV and 67% efficiency at 140 keV The detector fabrication, geometry and structure were optimized for charge collection and to minimize crosstalk between elements. A section of a standard high resolution cast-lead gamma-camera collimator was incorporated into the detector to provide collimation matching the discrete pixel geometry. Measurements of spectral and spatial performance of the array were made using 241-Am and 99m-Tc sources. These measurements were compared with similar measurements made using an optimized single HgI{sub 2} x-ray detector with active area of about 3 mm{sup 2} and thickness of 500 {mu}m.

  19. Proton Transfer Reactions Studied Using the VANDLE Neutron Detector Array

    NASA Astrophysics Data System (ADS)

    Thornsberry, C. R.; Burcher, S.; Gryzwacz, R.; Jones, K. L.; Paulauskas, S. V.; Smith, K.; Vostinar, M.; Allen, J.; Bardayan, D. W.; Blankstein, D.; Deboer, J.; Hall, M.; O'Malley, P. D.; Reingold, C.; Tan, W.; Cizewski, J. A.; Lepailleur, A.; Walter, D.; Febbraro, M.; Pain, S. D.; Marley, S. T.

    2016-09-01

    Proton transfer reactions, such as (d,n), are powerful tools for the study of single particle proton states of exotic nuclei. Measuring the outgoing neutron allows for the extraction of spectroscopic information from the recoil nucleus. With the development of new radioactive ion beam facilities, such as FRIB in the U.S., comes the need for new tools for the study of reactions involving radioactive nuclei. Neutron detectors, such as VANDLE, are sensitive to gamma rays in addition to neutrons. This results in high background rates for measurements with high external trigger rates. The use of discriminating recoil particle detectors, such as phoswich detectors, allow for the selection of a clean recoil tag by separating the recoil nucleus of interest from unreacted RIB components. Developments of low energy proton transfer measurements in inverse kinematics and recent (d,n) results will be presented. This work supported in part by the U.S. Department of Energy and the National Science Foundation.

  20. The DUV Stability of Superlattice-Doped CMOS Detector Arrays

    NASA Technical Reports Server (NTRS)

    Hoenk, M. E.; Carver, A. G.; Jones, T.; Dickie, M.; Cheng, P.; Greer, H. F.; Nikzad, S.; Sgro, J.; Tsur, S.

    2013-01-01

    JPL and Alacron have recently developed a high performance, DUV camera with a superlattice doped CMOS imaging detector. Supperlattice doped detectors achieve nearly 100% internal quantum efficiency in the deep and far ultraviolet, and a single layer, Al2O3 antireflection coating enables 64% external quantum efficiency at 263nm. In lifetime tests performed at Applied Materials using 263 nm pulsed, solid state and 193 nm pulsed excimer laser, the quantum efficiency and dark current of the JPL/Alacron camera remained stable to better than 1% precision during long-term exposure to several billion laser pulses, with no measurable degradation, no blooming and no image memory at 1000 fps.

  1. Development of a forward-angle gamma-ray detector array for MoNA-LISA

    NASA Astrophysics Data System (ADS)

    Votaw, Daniel; MoNA Collaboration Collaboration

    2017-01-01

    In recent years invariant mass spectroscopy has been successfully applied to measure neutron-unbound states. In this method neutrons are measured in coincidence with charged fragments following reactions with radioactive beams produced in projectile fragmentation reactions. When the final nucleus has bound excited states it is necessary to include gamma-ray detection in order to extract the excitation energy of the initial state. Because the MoNA-LISA setup at NSCL uses a large-gap Sweeper magnet to deflect the charged particles, conventional gamma-ray scintillation arrays cannot be used efficiently because of the large fringe field of the magnet. Thus we are developing a small cesium iodide (CsI) array using silicon photomultipliers (SiPMs) which are agnostic to the presence of a magnetic field. Using GEANT4 simulations the parameters of the array will be optimized to achieve the required efficiency and energy resolution of the Doppler-corrected energy spectra, necessary to extract the gamma-ray transitions in the final nucleus. NSF PHY-1002511, DOE-NNSA DE-NA0000979.

  2. Zonal wavefront sensor with reduced number of rows in the detector array.

    PubMed

    Boruah, Bosanta R; Das, Abhijit

    2011-07-10

    In this paper, we describe a zonal wavefront sensor in which the photodetector array can have a smaller number of rows. The test wavefront is incident on a two-dimensional array of diffraction gratings followed by a single focusing lens. The periodicity and the orientation of the grating rulings of each grating can be chosen such that the +1 order beam from the gratings forms an array of focal spots in the detector plane. We show that by using a square array of zones, it is possible to generate an array of +1 order focal spots having a smaller number of rows, thus reducing the height of the required detector array. The phase profile of the test wavefront can be estimated by measuring the displacements of the +1 order focal spots for the test wavefront relative to the +1 order focal spots for a plane reference wavefront. The narrower width of the photodetector array can offer several advantages, such as a faster frame rate of the wavefront sensor, a reduced amount of cross talk between the nearby detector zones, and a decrease in the maximum thermal noise. We also present experimental results of a proof-of-concept experimental arrangement using the proposed wavefront sensing scheme.

  3. Application and Design of Satellite Infrared Spectral Imaging Radiometers with Uncooled Microbolometer Array Detectors

    NASA Technical Reports Server (NTRS)

    Spinhirne, James; Lancaster, Regie; Maschhoff, Kevin; Starr, David OC (Technical Monitor)

    2001-01-01

    Uncooled infrared microbolometer array detectors have application for space borne spectral imaging radiometer of several types to lower size, power and cost and provide improved performance. Other advantages of eliminating cooling requirement are simplified systems, simplified satellite integration and improved reliability. A prototype microbolometer instrument for cloud observations was flown on the STS-85 space shuttle mission. Extensive data were acquired at_km resolution at four thermal infrared wavelength bands. From the 320x280 detector array both spectral and angular information can be used to advantage in cloud retrievals and has been demonstrated. An engineering model Compact Visible and Infrared Imaging Radiometer (COVIR) for small satellite missions has been developed. Application of advanced microbolometer array detectors for three axis stabilized GOES thermal imagers has been studied.

  4. Analysis of upper and lower bounds of the frame noise in linear detector arrays

    NASA Technical Reports Server (NTRS)

    Jaggi, S.

    1991-01-01

    This paper estimates the upper and lower bounds of the frame noise of a linear detector array that uses a one-dimensional scan pattern. Using chi-square distribution, it is analytically shown why it is necessary to use the average of the variances and not the average of the standard deviations to estimate these bounds. Also, a criteria for determining whether any excessively noisy lines exist among the detectors is derived from these bounds. Using a Gaussian standard random variable generator, these bounds are demonstrated to be accurate within the specified confidence interval. A silicon detector array is then used for actual dark current measurements. The criterion developed for determination of noisy detectors is checked on the experimentally obtained data.

  5. Application of neural networks to digital pulse shape analysis for an array of silicon strip detectors

    NASA Astrophysics Data System (ADS)

    Flores, J. L.; Martel, I.; Jiménez, R.; Galán, J.; Salmerón, P.

    2016-09-01

    The new generation of nuclear physics detectors that used to study nuclear reactions is considering the use of digital pulse shape analysis techniques (DPSA) to obtain the (A,Z) values of the reaction products impinging in solid state detectors. This technique can be an important tool for selecting the relevant reaction channels at the HYDE (HYbrid DEtector ball array) silicon array foreseen for the Low Energy Branch of the FAIR facility (Darmstadt, Germany). In this work we study the feasibility of using artificial neural networks (ANNs) for particle identification with silicon detectors. Multilayer Perceptron networks were trained and tested with recent experimental data, showing excellent identification capabilities with signals of several isotopes ranging from 12C up to 84Kr, yielding higher discrimination rates than any other previously reported.

  6. Parasitic antenna effect in terahertz plasmon detector array for real-time imaging system

    NASA Astrophysics Data System (ADS)

    Yang, Jong-Ryul; Lee, Woo-Jae; Ryu, Min Woo; Rok Kim, Kyung; Han, Seong-Tae

    2015-10-01

    The performance uniformity of each pixel integrated with a patch antenna in a terahertz plasmon detector array is very important in building the large array necessary for a real-time imaging system. We found a parasitic antenna effect in the terahertz plasmon detector whose response is dependent on the position of the detector pixel in the illumination area of the terahertz beam. It was also demonstrated that the parasitic antenna effect is attributed to the physical structure consisting of signal pads, bonding wires, and interconnection lines on a chip and a printed circuit board. Experimental results show that the performance of the detector pixel is determined by the sum of the effects of each parasitic antenna and the on-chip integrated antenna designed to detect signals at the operating frequency. The parasitic antenna effect can be minimized by blocking the interconnections with a metallic shield.

  7. Measurements and analysis of optical crosstalk in a microwave kinetic inductance detector array

    NASA Astrophysics Data System (ADS)

    Bisigello, L.; Yates, S. J. C.; Ferrari, L.; Baselmans, J. J. A.; Baryshev, A.

    2016-07-01

    The main advantage of Microwave Kinetic Inductance Detector arrays (MKID) is their multiplexing capability, which allows for building cameras with a large number of pixels and good sensitivity, particularly suitable to perform large blank galaxy surveys. However, to have as many pixels as possible it is necessary to arrange detectors close in readout frequency. Consequently KIDs overlap in frequency and are coupled to each other producing crosstalk. Because crosstalk can be only minimised by improving the array design, in this work we aim to correct for this effect a posteriori. We analysed a MKID array consisting of 880 KIDs with readout frequencies at 4-8 GHz. We measured the beam patterns for every detector in the array and described the response of each detector by using a two-dimensional Gaussian fit. Then, we identified detectors affected by crosstalk above -30 dB level from the maximum and removed the signal of the crosstalking detectors. Moreover, we modelled the crosstalk level for each KID as a function of the readout frequency separation starting from the assumption that the transmission of a KID is a Lorenztian function in power. We were able to describe the general crosstalk level of the array and the crosstalk of each KID within 5 dB, so enabling the design of future arrays with the crosstalk as a design criterion. In this work, we demonstrate that it is possible to process MKID images a posteriori to decrease the crosstalk effect, subtracting the response of each coupled KID from the original map.

  8. Hybrid Extensive Air Shower Detector Array at the University of Puebla to Study Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Martínez, O.; Pérez, E.; Salazar, H.; Villaseñor, L.

    We describe the design of an extensive air shower detector array built in the Campus of the University of Puebla (located at 19°N, 90°W, 800 gcm -2) to measure the energy and arrival direction of primary cosmic rays with energies around 1015 eV. The array consists of 18 liquid scintillator detectors (12 in the first stage) and 6 water Cherenkov detectors (one of 10 m 2 cross section and five smaller ones of 1.86 m 2 cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m 2. In this paper we discuss the calibration and stability of the array, and discuss the capability of hybrid arrays, such as this one consisting of water Cherenkov and liquid scintillator detectors, to allow a separation of the electromagnetic and muon components of extensive air showers. This separation plays an important role in the determination of the mass and identity of the primary cosmic ray. This facility is also used to train students interested in the field of cosmic rays.

  9. The water Cherenkov detector array for studies of cosmic rays at the University of Puebla

    NASA Astrophysics Data System (ADS)

    Cotzomi, J.; Moreno, E.; Murrieta, T.; Palma, B.; Pérez, E.; Salazar, H.; Villaseñor, L.

    2005-11-01

    We describe the design and performance of a hybrid extensive air shower detector array built on the Campus of the University of Puebla ( 19∘N, 90∘W, 800 g/cm2) to measure the energy, arrival direction and composition of primary cosmic rays with energies around 1 PeV, i.e., around the knee of the cosmic ray spectrum. The array consists of 3 water Cherenkov detectors of 1.86 m2 cross-section and 12 liquid scintillator detectors of 1 m2 distributed in a square grid with a detector spacing of 20 m over an area of 4000 m2. We discuss the calibration and stability of the array for both sets of detectors and report on preliminary measurements and reconstruction of the lateral distributions for the electromagnetic (EM) and muonic components of extensive air showers. We also discuss how the hybrid character of the array can be used to measure mass composition of the primary cosmic rays by estimating the relative contents of muons with respect to the EM component of extensive air showers. This facility is also used to train students interested in the field of cosmic rays.

  10. A sub-millimeter resolution PET detector module using a multi-pixel photon counter array

    PubMed Central

    Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B; Tai, Yuan-Chuan

    2010-01-01

    A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 × 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 × 0.8 × 3 mm3 and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 × 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and ±5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when ±10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing

  11. 20 element HgI sub 2 energy dispersive x-ray array detector system

    SciTech Connect

    Iwanczyk, J.A.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. ); Hedman, B.; Hodgson, K.O. . Stanford Synchrotron Radiation Lab.); Patt, B.E. )

    1991-01-01

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K{sub a}) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  12. 20 element HgI{sub 2} energy dispersive x-ray array detector system

    SciTech Connect

    Iwanczyk, J.A.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J.; Hedman, B.; Hodgson, K.O.; Patt, B.E.

    1991-12-31

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K{sub a}) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  13. Extensive Air Shower Detector Array at the Universidad Autonoma de Puebla

    NASA Astrophysics Data System (ADS)

    Cotzomi, J.; Moreno, E.; Aguilar, S.; Palma, B.; Martinez, O.; Salazar, H.; Villasenor, L.

    2002-07-01

    We describe the operation of an Extensive Air Shower Array located at the campus of the FCFM-BUAP. The array consists of 8 liquid scintillation detectors with a surface of 1 m2 each and a detector spacing of 20 m in a square grid. The array was designed to measure the energy and arrival direction of primary particles that generate extensive air showers (EAS) in the region of 1013 eV - 1016 eV. The angular distribution measured with this array, Cos8(Theta) xSin(Theta), agrees very well with the literature. We also present the measured energies of a number of vertical showers in the range of 5 x1012 eV to 5 x1013 eV.

  14. Implementation of digital multiplexing for high resolution X-ray detector arrays.

    PubMed

    Sharma, P; Swetadri Vasan, S N; Titus, A H; Cartwright, A N; Bednarek, D R; Rudin, S

    2012-01-01

    We describe and demonstrate for the first time the use of the novel Multiple Module Multiplexer (MMMIC) for a 2×2 array of new electron multiplying charge coupled device (EMCCD) based x-ray detectors. It is highly desirable for x-ray imaging systems to have larger fields of view (FOV) extensible in two directions yet to still be capable of doing high resolution imaging over regions-of-interest (ROI). The MMMIC achieves these goals by acquiring and multiplexing data from an array of imaging modules thereby enabling a larger FOV, and at the same time allowing high resolution ROI imaging through selection of a subset of modules in the array. MMMIC also supports different binning modes. This paper describes how a specific two stage configuration connecting three identical MMMICs is used to acquire and multiplex data from a 2×2 array of EMCCD based detectors. The first stage contains two MMMICs wherein each MMMIC is getting data from two EMCCD detectors. The multiplexed data from these MMMICs is then forwarded to the second stage MMMIC in the similar fashion. The second stage that has only one MMMIC gives the final 12 bit multiplexed data from four modules. This data is then sent over a high speed Camera Link interface to the image processing computer. X-ray images taken through the 2×2 array of EMCCD based detectors using this two stage configuration of MMMICs are shown successfully demonstrating the concept.

  15. Performances Of Arrays Of Ge:Ga Far-Infrared Detectors

    NASA Technical Reports Server (NTRS)

    Mccreight, C.; Farhoomand, J.

    1992-01-01

    Report presents evaluation of performances of two electronic modules containing few-element linear focal-plane arrays of Ge:Ga photodetectors and associated multiplexing readout circuitry. Tested to demonstrate feasibility of many-element, two-dimensional focal-plane arrays of far-infrared detectors and associated circuitry for use in astronomical and other low-background scientific observations. Revealed deficiencies that must be overcome in future designs.

  16. Multispectral Detector Based on Array of Carbon-Nanotube Quantum Wells

    DTIC Science & Technology

    2009-09-30

    2006-Mar 2009 4. TITLE AND SUBTITLE MULTISPECTRAL DETECTOR BASED ON AN ARRAY OF CARBON- NANOTUBE QUANTUM WELLS 5. FUNDING NUMBERS FA9550-06-1-0366...carbon nanotube quantum wells exposed to external weak THz fields. Each of the individual well in the array had been independently controlled by a dc...the intrinsic noises considerably. 14. SUBJECT TERMS 15. NUMBER OF PAGES 23 THz field nanosensors, carbon nanotube quantum wells, Luttinger

  17. Confined Space Imager (CSI) Software

    SciTech Connect

    Karelilz, David

    2013-07-03

    The software provides real-time image capture, enhancement, and display, and sensor control for the Confined Space Imager (CSI) sensor system The software captures images over a Cameralink connection and provides the following image enhancements: camera pixel to pixel non-uniformity correction, optical distortion correction, image registration and averaging, and illumination non-uniformity correction. The software communicates with the custom CSI hardware over USB to control sensor parameters and is capable of saving enhanced sensor images to an external USB drive. The software provides sensor control, image capture, enhancement, and display for the CSI sensor system. It is designed to work with the custom hardware.

  18. The DUV Stability of Superlattice-Doped CMOS Detector Arrays

    NASA Technical Reports Server (NTRS)

    Hoenk, M. E.; Carver, A.; Jones, T.; Dickie, M.; Cheng, P.; Greer, H. F.; Nikzad, S.; Sgro, J.

    2013-01-01

    In this paper, we present experimental results and band structure calculations that illuminate the unique properties of superlattice-doped detectors. Numerical band structure calculations are presented to analyze the dependencies of surface passivation on dopant profiles and interface trap densities (Figure 3). Experiments and calculations show that quantum-engineered surfaces, grown at JPL by low temperature molecular beam epitaxy, achieve a qualitative as well as quantitative uniqueness in their near-immunity to high densities of surface and interface traps.

  19. Circuit for high resolution decoding of multi-anode microchannel array detectors

    NASA Technical Reports Server (NTRS)

    Kasle, David B. (Inventor)

    1995-01-01

    A circuit for high resolution decoding of multi-anode microchannel array detectors consisting of input registers accepting transient inputs from the anode array; anode encoding logic circuits connected to the input registers; midpoint pipeline registers connected to the anode encoding logic circuits; and pixel decoding logic circuits connected to the midpoint pipeline registers is described. A high resolution algorithm circuit operates in parallel with the pixel decoding logic circuit and computes a high resolution least significant bit to enhance the multianode microchannel array detector's spatial resolution by halving the pixel size and doubling the number of pixels in each axis of the anode array. A multiplexer is connected to the pixel decoding logic circuit and allows a user selectable pixel address output according to the actual multi-anode microchannel array detector anode array size. An output register concatenates the high resolution least significant bit onto the standard ten bit pixel address location to provide an eleven bit pixel address, and also stores the full eleven bit pixel address. A timing and control state machine is connected to the input registers, the anode encoding logic circuits, and the output register for managing the overall operation of the circuit.

  20. Laboratory characterization of direct readout Si:Sb and Si:Ga infrared detector arrays

    NASA Technical Reports Server (NTRS)

    Mckelvey, Mark E.; Moss, Nicolas N.; Mcmurray, R. E., Jr.; Estrada, John A.; Goebel, John H.; Mccreight, Craig R.; Savage, Maureen L.; Junga, Frank; Whittemore, Thomas

    1989-01-01

    Highlights of recent results obtained at Ames Research Center in performance evaluations of infrared detector arrays are presented. Antimony- and gallium-doped silicon direct readout 58x62 element hybrid devices from Ames' ongoing detector technology development program are described. The observed characteristics meet most of the performance goals specified by the Space Infrared Telescope Facility (SIRTF) instrument teams and compare favorably with the best performance reported for discrete non-integrating extrinsic silicon detectors. Initial results of radiation environment testing are reported, and non-ideal behavior demonstrated by these test devices is discussed.

  1. Experience using an automated fault location system with a time-of-flight wall detector array

    NASA Astrophysics Data System (ADS)

    Olson, D.; Greiman, W.; Hall, D.; Balaban, D.; Day, C.

    1990-08-01

    We describe the architecture of a general purpose monitoring system and give examples of its use with a 300 element detector array in a relativistic heavy ion experiment. The system has a simple and well defined interface between the detector specific parts of the system and those which are independent of any detector specific features. Tracking simple statistics on the fundamental data items (ADC and TDC values) are sufficient to diagnose the higher level components in the system. The monitoring of on-line beam data provides a sensitive monitor of global parameters of the experiment.

  2. X-ray source considerations in operation of digital detector arrays

    SciTech Connect

    Jensen, Terrence; Wendt, Scott

    2014-02-18

    Digital Detector Arrays (DDA) are increasingly replacing film in radiography applications. Standards exist for characterizing the performance of these detectors, and for using them in specific inspections. We have observed that the selection of the x-ray source to use with these detectors can also have a significant influence on the performance. We look at differences between standard, and micro-focus x-ray tubes, and end-window vs. side-window micro-focus tubes. We find that for best results, one must calibrate the DDA for the source settings used during an inspection. This is particularly true for variable-focus sources.

  3. Detector Arrays for the James Webb Space Telescope Near-Infrared Spectrograph

    NASA Technical Reports Server (NTRS)

    Rauscher, Bernard J.; Alexander, David; Brambora, Clifford K.; Derro, Rebecca; Engler, Chuck; Fox, Ori; Garrison, Matthew B.; Henegar, Greg; Hill, robert J.; Johnson, Thomas; Lindler, Don J.; Manthripragada, Sridhar S.; Marshall, Ceryl; Mott, Brent; Parr, Thomas M.; Roher, Wayne D.; Shakoorzadeh, Kamdin B.; Smith, Miles; Waczynski, Augustyn; Wen, Yiting; Wilson, Donna; Xia-Serafino, Wei

    2007-01-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 micron cutoff (lambda(sub co) = 5 microns) 2048x2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T approx. 37 K. In this article, we provide a brief introduction to NIRSpec, its detector subsystem (DS), detector readout in the space radiation environment, and present a snapshot of the developmental status of the NIRSpec DS as integration and testing of the engineering test unit begins.

  4. A 4 π charged-particle detector array for light-ion-induced nuclear fragmentation studies

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, K.; Alexander, A.; Bracken, D. S.; Brzychczyk, J.; Dorsett, J.; Ensman, R.; Renshaw Foxford, E.; Hamilton, T.; Komisarcik, K.; McDonald, K. N.; Morley, K. B.; Poehlman, J.; Powell, C.; Viola, V. E.; Yoder, N. R.; Ottarson, J.; Madden, N.

    1994-12-01

    Operating characteristics of the Indiana Silicon Sphere 4 π detector array are outlined. The detector geometry is spherical, with 90 telescopes in the forward hemisphere and 72 at backward angles, covering a total solid angle of 74% of 4π. Each telescope consists of a simple gas-ion chamber, operated with C3F8 gas, followed by a 0.5 mm thick ion-implanted silicon detector and a 28 mm CsI(Tl) crystal, readout by a photodiode. Custom-built bias supplies and NIM preamp/shaper modules were used in conjunction with commercial CFD, TDC and ADC CAMAC units.

  5. THz Direct Detector and Heterodyne Receiver Arrays in Silicon Nanoscale Technologies

    NASA Astrophysics Data System (ADS)

    Grzyb, Janusz; Pfeiffer, Ullrich

    2015-10-01

    The main scope of this paper is to address various implementation aspects of THz detector arrays in the nanoscale silicon technologies operating at room temperatures. This includes the operation of single detectors, detectors operated in parallel (arrays), and arrays of detectors operated in a video-camera mode with an internal reset to support continuous-wave illumination without the need to synchronize the source with the camera (no lock-in receiver required). A systematic overview of the main advantages and limitations in using silicon technologies for THz applications is given. The on-chip antenna design challenges and co-design aspects with the active circuitry are thoroughly analyzed for broadband detector/receiver operation. A summary of the state-of-the-art arrays of broadband THz direct detectors based on two different operation principles is presented. The first is based on the non-quasistatic resistive mixing process in a MOSFET channel, whereas the other relies on the THz signal rectification by nonlinearity of the base-emitter junction in a high-speed SiGe heterojunction bipolar transistor (HBT). For the MOSFET detector arrays implemented in a 65 nm bulk CMOS technology, a state-of-the-art optical noise equivalent power (NEP) of 14 pW/ at 720 GHz was measured, whereas for the HBT detector arrays in a 0.25 μm SiGe process technology, an optical NEP of 47 pW/ at 700 GHz was found. Based on the implemented 1k-pixel CMOS camera with an average power consumption of 2.5 μW/pixel, various design aspects specific to video-mode operation are outlined and co-integration issues with the readout circuitry are analyzed. Furthermore, a single-chip 2 × 2 array of heterodyne receivers for multi-color active imaging in a 160-1000 GHz band is presented with a well-balanced NEP across the operation bandwidth ranging from 0.1 to 0.24 fW/Hz (44.1-47.8 dB single-sideband NF) and an instantaneous IF bandwidth of 10 GHz. In its present implementation, the receiver RF

  6. Versatile, reprogrammable area pixel array detector for time-resolved synchrotron x-ray applications

    SciTech Connect

    Gruner, Sol

    2010-05-01

    The final technical report for DOE grant DE-SC0004079 is presented. The goal of the grant was to perform research, development and application of novel imaging x-ray detectors so as to effectively utilize the high intensity and brightness of the national synchrotron radiation facilities to enable previously unfeasible time-resolved x-ray research. The report summarizes the development of the resultant imaging x-ray detectors. Two types of detector platforms were developed: The first is a detector platform (called a Mixed-Mode Pixel Array Detector, or MM-PAD) that can image continuously at over a thousand images per second while maintaining high efficiency for wide dynamic range signals ranging from 1 to hundreds of millions of x-rays per pixel per image. Research on an even higher dynamic range variant is also described. The second detector platform (called the Keck Pixel Array Detector) is capable of acquiring a burst of x-ray images at a rate of millions of images per second.

  7. Coherent Detector Arrays for Millimeter and Submillimeter Astronomy

    NASA Astrophysics Data System (ADS)

    Goldsmith, Paul F.; Carpenter, John; Erickson, Neal; Fisher, Rick; Ford, John; Gaier, Todd; Groppi, Chris; Harris, Andy; Heyer, Mark; Kulesa, Craig; Lawrence, Charles; Morgan, Matt; Mundy, Lee; Narayanan, Gopal; O'Neil, Karen; Readhead, Tony; Samoska, Lorene; Schloerb, Peter; Snell, Ron; Walker, Christopher; Ziurys, Lucy

    2009-03-01

    Progress in many areas of astronomy requires large-area surveys and observations of extended objects. This includes the cosmic microwave background, nearby galaxies, the Milky Way, and regions of star-forming regions within our galaxy. The ability to carry out such studies is critically dependent on the development of affordable high-sensitivity focal plane arrays, for both spectral line and continuum observations. We discuss a program for the next decade to develop such technology for ground-based and spacebased millimeter and submillimeter astronomy. Appropriate technologies exist, but significant effort is required to make the transition from simply replicating individual pixels to approaching focal plane array design in an integrated fashion from feeds to spectrometers for spectral analysis. This advance is essential to realize the full potential of major new ground-based, suborbital, and future space facilities, and is relevant to the RMS and EOS panels. The recommended budget for this activity is $65M.

  8. Development of 256 x 256 Element Impurity Band Conduction Infrared Detector Arrays for Astronomy

    NASA Technical Reports Server (NTRS)

    Domingo, George

    1997-01-01

    This report describes the work performed on a one and a half year advance technology program to develop Impurity Band Conduction (IBC) detectors with very low dark current, high quantum efficiency, and with good repeatable processes. The program fabricated several epitaxial growths of Si:As detecting layers from 15 to 35 microns thick and analyzed the performance versus the thickness and the Arsenic concentration of these epitaxial layers. Some of the epitaxial runs did not yield because of excessive residual impurities. The thicker epitaxial layers and the ones with higher Arsenic concentration resulted in good detectors with low dark currents and good quantum efficiency. The program hybridized six detector die from the best detector wafers to a low noise, 256 x 256 readout array and delivered the hybrids to NASA Ames for a more detailed study of the performance of the detectors.

  9. Digital Radiography and Computed Tomography Project -- Fully Integrated Linear Detector ArrayStatus Report

    SciTech Connect

    Tim Roney; Robert Seifert; Bob Pink; Mike Smith

    2011-09-01

    The field-portable Digital Radiography and Computed Tomography (DRCT) x-ray inspection systems developed for the Project Manager for NonStockpile Chemical Materiel (PMNSCM) over the past 13 years have used linear diode detector arrays from two manufacturers; Thomson and Thales. These two manufacturers no longer produce this type of detector. In the interest of insuring the long term viability of the portable DRCT single munitions inspection systems and to improve the imaging capabilities, this project has been investigating improved, commercially available detectors. During FY-10, detectors were evaluated and one in particular, manufactured by Detection Technologies (DT), Inc, was acquired for possible integration into the DRCT systems. The remainder of this report describes the work performed in FY-11 to complete evaluations and fully integrate the detector onto a representative DRCT platform.

  10. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.

    PubMed

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-07

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  11. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  12. Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration

    DTIC Science & Technology

    2008-09-01

    correlation coefficient (CC), or some comparable detection statistic, exceeds a given threshold. Since these methods exploit characteristic details of the...multiple channels since stacking can be performed on the correlation coefficient traces with a significant array-gain. A detected event that is co-located...with the master event will record the same time-difference at every site in an arbitrarily spaced network which means that the correlation coefficient traces

  13. Silicon Wafer-Scale Substrate for Microshutters and Detector Arrays

    NASA Technical Reports Server (NTRS)

    Jhabvala, Murzy; Franz, David E.; Ewin, Audrey J.; Jhabvala, Christine; Babu, Sachi; Snodgrass, Stephen; Costen, Nicholas; Zincke, Christian

    2009-01-01

    The silicon substrate carrier was created so that a large-area array (in this case 62,000+ elements of a microshutter array) and a variety of discrete passive and active devices could be mounted on a single board, similar to a printed circuit board. However, the density and number of interconnects far exceeds the capabilities of printed circuit board technology. To overcome this hurdle, a method was developed to fabricate this carrier out of silicon and implement silicon integrated circuit (IC) technology. This method achieves a large number of high-density metal interconnects; a 100-percent yield over a 6-in. (approximately equal to 15-cm) diameter wafer (one unit per wafer); a rigid, thermally compatible structure (all components and operating conditions) to cryogenic temperatures; re-workability and component replaceability, if required; and the ability to precisely cut large-area holes through the substrate. A method that would employ indium bump technology along with wafer-scale integration onto a silicon carrier was also developed. By establishing a silicon-based version of a printed circuit board, the objectives could be met with one solution. The silicon substrate would be 2 mm thick to survive the environmental loads of a launch. More than 2,300 metal traces and over 1,500 individual wire bonds are required. To mate the microshutter array to the silicon substrate, more than 10,000 indium bumps are required. A window was cut in the substrate to allow the light signal to pass through the substrate and reach the microshutter array. The substrate was also the receptacle for multiple unpackaged IC die wire-bonded directly to the substrate (thus conserving space over conventionally packaged die). Unique features of this technology include the implementation of a 2-mmthick silicon wafer to withstand extreme mechanical loads (from a rocket launch); integrated polysilicon resistor heaters directly on the substrate; the precise formation of an open aperture

  14. Development and test of photon-counting microchannel plate detector arrays for use on space telescopes

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1976-01-01

    The full sensitivity, dynamic range, and photometric stability of microchannel array plates(MCP) are incorporated into a photon-counting detection system for space operations. Components of the system include feedback-free MCP's for high gain and saturated output pulse-height distribution with a stable response; multi-anode readout arrays mounted in proximity focus with the output face of the MCP; and multi-layer ceramic headers to provide electrical interface between the anode array in a sealed detector tube and the associated electronics.

  15. Uniform Non-stoichiometric Titanium Nitride Thin Films for Improved Kinetic Inductance Detector Arrays

    NASA Astrophysics Data System (ADS)

    Coiffard, G.; Schuster, K.-F.; Driessen, E. F. C.; Pignard, S.; Calvo, M.; Catalano, A.; Goupy, J.; Monfardini, A.

    2016-08-01

    We describe the fabrication of homogeneous sub-stoichiometric titanium nitride films for microwave kinetic inductance detector (KID) arrays. Using a 6'' sputtering target and a homogeneous nitrogen inlet, the variation of the critical temperature over a 2'' wafer was reduced to {<}25 %. Measurements of a 132-pixel KID arrays from these films reveal a sensitivity of 16 kHz/pW in the 100 GHz band, comparable to the best aluminum KIDs. We measured a noise equivalent power of NEP = 3.6× 10^{-15} W/Hz^{1/2}. Finally, we describe possible routes to further improve the performance of these TiN KID arrays.

  16. Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration

    DTIC Science & Technology

    2007-09-01

    correlation coefficient , or some comparable detection statistic, exceeds a given threshold. Since these methods exploit characteristic details of the full waveform, they provide exquisitely sensitive detectors with far lower detection thresholds than typical short-term average/long-term average (STA/LTA) algorithms. The drawback is that the form of the sought-after signal needs to be known quite accurately a priori, which limits such methods to instances of seismicity whereby a very similar signal has already been observed by every station used. Such instances include

  17. Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA

    NASA Astrophysics Data System (ADS)

    Hüyük, Tayfun; Di Nitto, Antonio; Jaworski, Grzegorz; Gadea, Andrés; Javier Valiente-Dobón, José; Nyberg, Johan; Palacz, Marcin; Söderström, Pär-Anders; Jose Aliaga-Varea, Ramon; de Angelis, Giacomo; Ataç, Ayşe; Collado, Javier; Domingo-Pardo, Cesar; Egea, Francisco Javier; Erduran, Nizamettin; Ertürk, Sefa; de France, Gilles; Gadea, Rafael; González, Vicente; Herrero-Bosch, Vicente; Kaşkaş, Ayşe; Modamio, Victor; Moszynski, Marek; Sanchis, Enrique; Triossi, Andrea; Wadsworth, Robert

    2016-03-01

    The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large γ-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23l and it is filled with the EJ301 liquid scintillator, that presents good neutron- γ discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the 58Ni + 56Fe reaction measured with the Neutron Wall detector array.

  18. Converting films for X-ray detectors, applied to amorphous silicon arrays

    SciTech Connect

    Ross, S.; Zentai, G.

    1998-12-31

    This paper presents results from the on-going efforts to characterize semiconductor thin films for direct X-ray conversion. The authors deposit these thin films onto an amorphous silicon (a-Si:H) readout array with the overall goal of developing a large area X-ray detector for protein crystallography, and for other X-ray imaging fields.

  19. Converting films for x-ray detectors, applied to amorphous silicon arrays.

    SciTech Connect

    Ross, S.; Zentai, G.

    1997-12-05

    This paper presents results from our on-going efforts to characterize semiconductor thin films for direct x-ray conversion. We deposit these thin films onto an amorphous silicon (a-Si:H) readout array with the overall goal of developing a large area x-ray detector for protein crystallography, and for other x-ray imaging fields.

  20. First Data with the Hybrid Array of Gamma-Ray Detectors (HAGRiD)

    NASA Astrophysics Data System (ADS)

    Smith, Karl; Burcher, S.; Carter, A. B.; Gryzwacz, R.; Jones, K. L.; Munoz, S.; Paulauskas, S. V.; Schmitt, K.; Thornsberry, C.; Chipps, K. A.; Febbraro, M.; Pain, S. D.; Baugher, T.; Cizewski, J. A.; Ratkiewicz, A.; Toomey, B.

    2016-09-01

    The structure of nuclei provides insight into astrophysical reaction rates that are difficult to measure directly. These studies are often performed with transfer reaction and beta-decay measurements. These experiments benefit from particle-gamma coincident measurements providing information beyond that of particle detection alone. The Hybrid Array of Gamma Ray Detectors (HAGRiD) of LaBr3(Ce) scintillators has been designed with this purpose in mind. The design of the array permits it to be coupled with particle detector systems, such as the Oak Ridge Rutgers University Barrel Array (ORRUBA) of silicon detectors and the Versatile Array of Neutron Detectors at Low Energy (VANDLE). It is also designed to operate with the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) advanced target system. HAGRiD's design avoids compromising the charged-particle angular resolution due to compact geometries often used to increase the gamma efficiency in other systems. First experimental data with HAGRiD coupled to VANDLE as well as ORRUBA and JENSA will be presented. This work is supported in part by the U.S. Department of Energy, Office of Science Nuclear Physics and the National Science Foundation.

  1. Arrays of Encapsulated CdZnTe Gamma-Ray Detectors for Planetary Missions

    NASA Technical Reports Server (NTRS)

    Moss, C. E.; Ianakiev, K. D.; Prettyman, T. H.; Reedy, R. C.; Smith, M. K.; Sweet, M. R.

    2000-01-01

    Recent results from encapsulated multi-element CdZnTe room-temperature semiconductor gamma-ray detectors are presented. Our multi-element-array design is a good low-mass and low-power candidate for elemental mapping on future planetary missions.

  2. High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy.

    PubMed

    Tate, Mark W; Purohit, Prafull; Chamberlain, Darol; Nguyen, Kayla X; Hovden, Robert; Chang, Celesta S; Deb, Pratiti; Turgut, Emrah; Heron, John T; Schlom, Darrell G; Ralph, Daniel C; Fuchs, Gregory D; Shanks, Katherine S; Philipp, Hugh T; Muller, David A; Gruner, Sol M

    2016-02-01

    We describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500 µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition system, and preliminary results from experiments with 80-200 keV electron beams.

  3. The Belle detector

    NASA Astrophysics Data System (ADS)

    Abashian, A.; Gotow, K.; Morgan, N.; Piilonen, L.; Schrenk, S.; Abe, K.; Adachi, I.; Alexander, J. P.; Aoki, K.; Behari, S.; Doi, Y.; Enomoto, R.; Fujii, H.; Fujita, Y.; Funahashi, Y.; Haba, J.; Hamasaki, H.; Haruyama, T.; Hayashi, K.; Higashi, Y.; Hitomi, N.; Igarashi, S.; Igarashi, Y.; Iijima, T.; Ikeda, Hirokazu; Ikeda, Hitomi; Itoh, R.; Iwai, M.; Iwasaki, H.; Iwasaki, Y.; Joo, K. K.; Kasami, K.; Katayama, N.; Kawai, M.; Kichimi, H.; Kobayashi, T.; Koike, S.; Kondo, Y.; Lee, M. H.; Makida, Y.; Manabe, A.; Matsuda, T.; Murakami, T.; Nagayama, S.; Nakao, M.; Nozaki, T.; Ogawa, K.; Ohkubo, R.; Ohnishi, Y.; Ozaki, H.; Sagawa, H.; Saito, M.; Sakai, Y.; Sasaki, T.; Sato, N.; Sumiyoshi, T.; Suzuki, J.; Suzuki, J. I.; Suzuki, S.; Takasaki, F.; Tamai, K.; Tanaka, M.; Tatomi, T.; Tsuboyama, T.; Tsukada, K.; Tsukamoto, T.; Uehara, S.; Ujiie, N.; Uno, S.; Yabsley, B.; Yamada, Y.; Yamaguchi, H.; Yamaoka, H.; Yamaoka, Y.; Yamauchi, M.; Yoshimura, Y.; Zhao, H.; Abe, R.; Iwai, G.; Kawasaki, T.; Miyata, H.; Shimada, K.; Takahashi, S.; Tamura, N.; Abe, K.; Hanada, H.; Nagamine, T.; Nakajima, M.; Nakajima, T.; Narita, S.; Sanpei, M.; Takayama, T.; Ueki, M.; Yamaga, M.; Yamaguchi, A.; Ahn, B. S.; Kang, J. S.; Kim, Hyunwoo; Park, C. W.; Park, H.; Ahn, H. S.; Jang, H. K.; Kim, C. H.; Kim, S. K.; Lee, S. H.; Park, C. S.; Won, E.; Aihara, H.; Higuchi, T.; Kawai, H.; Matsubara, T.; Nakadaira, T.; Tajima, H.; Tanaka, J.; Tomura, T.; Yokoyama, M.; Akatsu, M.; Fujimoto, K.; Hirose, M.; Inami, K.; Ishikawa, A.; Itami, S.; Kani, T.; Matsumoto, T.; Nagai, I.; Okabe, T.; Oshima, T.; Senyo, K.; Sugi, A.; Sugiyama, A.; Suitoh, S.; Suzuki, S.; Tomoto, M.; Yoshida, K.; Akhmetshin, R.; Chang, P.; Chao, Y.; Chen, Y. Q.; Hou, W. S.; Hsu, S. C.; Huang, H. C.; Huang, T. J.; Lee, M. C.; Lu, R. S.; Peng, J. C.; Peng, K. C.; Sahu, S.; Sung, H. F.; Tsai, K. L.; Ueno, K.; Wang, C. C.; Wang, M. Z.; Alimonti, G.; Browder, T. E.; Casey, B. C. K.; Fang, F.; Guler, H.; Jones, M.; Li, Y.; Olsen, S. L.; Peters, M.; Rodriguez, J. L.; Rosen, M.; Swain, S.; Trabelsi, K.; Varner, G.; Yamamoto, H.; Zheng, Y. H.; An, Q.; Chen, H. F.; Wang, Y. F.; Xu, Z. Z.; Ye, S. W.; Zhang, Z. P.; Asai, M.; Asano, Y.; Mori, S.; Stanič, S.; Tsujita, Y.; Zhang, J.; Žontar, D.; Aso, T.; Aulchenko, V.; Beiline, D.; Bondar, A.; Dneprovsky, L.; Eidelman, S.; Garmash, A.; Kuzmin, A.; Romanov, L.; Root, N.; Shwartz, B.; Sidorov, A.; Sidorov, V.; Usov, Y.; Zhilich, V.; Bakich, A. M.; Peak, L. S.; Varvell, K. E.; Banas, E.; Bozek, A.; Jalocha, P.; Kapusta, P.; Natkaniec, Z.; Ostrowicz, W.; Palka, H.; Rozanka, M.; Rybicki, K.; Behera, P. K.; Mohapatra, A.; Satapathy, M.; Chang, Y. H.; Chen, H. S.; Dong, L. Y.; Li, J.; Liu, H. M.; Mao, Z. P.; Yu, C. X.; Zhang, C. C.; Zhang, S. Q.; Zhao, Z. G.; Zheng, Z. P.; Cheon, B. G.; Choi, Y.; Kim, D. W.; Nam, J. W.; Chidzik, S.; Korotuschenko, K.; Leonidopoulos, C.; Liu, T.; Marlow, D.; Mindas, C.; Prebys, E.; Rabberman, R.; Sands, W.; Wixted, R.; Choi, S.; Dragic, J.; Everton, C. W.; Gordon, A.; Hastings, N. C.; Heenan, E. M.; Moffitt, L. C.; Moloney, G. R.; Moorhead, G. F.; Sevior, M. E.; Taylor, G. N.; Tovey, S. N.; Drutskoy, A.; Kagan, R.; Pakhlov, P.; Semenov, S.; Fukunaga, C.; Suda, R.; Fukushima, M.; Goriletsky, V. I.; Grinyov, B. V.; Lyubinsky, V. R.; Panova, A. I.; Shakhova, K. V.; Shpilinskaya, L. I.; Vinograd, E. L.; Zaslavsky, B. G.; Guo, R. S.; Haitani, F.; Hoshi, Y.; Neichi, K.; Hara, K.; Hara, T.; Hazumi, M.; Hojo, T.; Jackson, D.; Miyake, H.; Nagashima, Y.; Ryuko, J.; Sumisawa, K.; Takita, M.; Yamanaka, T.; Hayashii, H.; Miyabayashi, K.; Noguchi, S.; Hikita, S.; Hirano, H.; Hoshina, K.; Mamada, H.; Nitoh, O.; Okazaki, N.; Yokoyama, T.; Ishino, H.; Ichizawa, S.; Hirai, T.; Kakuno, H.; Kaneko, J.; Nakamura, T.; Ohshima, Y.; Watanabe, Y.; Yanaka, S.; Inoue, Y.; Nakano, E.; Takahashi, T.; Teramoto, Y.; Kang, J. H.; Kim, H. J.; Kim, Heejong; Kwon, Y.-J.; Kawai, H.; Kurihara, E.; Ooba, T.; Suzuki, K.; Unno, Y.; Kawamura, N.; Yuta, H.; Kinoshita, K.; Satpathy, A.; Kobayashi, S.; Kuniya, T.; Murakami, A.; Tsukamoto, T.; Kumar, S.; Singh, J.; Lange, J.; Stock, R.; Matsumoto, S.; Watanabe, M.; Matsuo, H.; Nishida, S.; Nomura, T.; Sakamoto, H.; Sasao, N.; Ushiroda, Y.; Nagasaka, Y.; Tanaka, Y.; Ogawa, S.; Shibuya, H.; Hanagaki, K.; Okuno, S.; Shen, D. Z.; Yan, D. S.; Yin, Z. W.; Tan, N.; Wang, C. H.; Yamaki, T.; Yamashita, Y.

    2002-02-01

    The Belle detector was designed and constructed to carry out quantitative studies of rare B-meson decay modes with very small branching fractions using an asymmetric e +e - collider operating at the ϒ(4S) resonance, the KEK-B-factory. Such studies require data samples containing ˜10 7 B-meson decays. The Belle detector is configured around a 1.5 T superconducting solenoid and iron structure surrounding the KEK-B beams at the Tsukuba interaction region. B-meson decay vertices are measured by a silicon vertex detector situated just outside of a cylindrical beryllium beam pipe. Charged particle tracking is performed by a wire drift chamber (CDC). Particle identification is provided by d E/d x measurements in CDC, aerogel threshold Cherenkov counter and time-of-flight counter placed radially outside of CDC. Electromagnetic showers are detected in an array of CsI( Tl) crystals located inside the solenoid coil. Muons and K L mesons are identified by arrays of resistive plate counters interspersed in the iron yoke. The detector covers the θ region extending from 17° to 150°. The part of the uncovered small-angle region is instrumented with a pair of BGO crystal arrays placed on the surfaces of the QCS cryostats in the forward and backward directions. Details of the design and development works of the detector subsystems, which include trigger, data acquisition and computer systems, are described. Results of performance of the detector subsystems are also presented.

  4. Multiple detector focal plane array ultraviolet spectrometer for the AMPS laboratory

    NASA Technical Reports Server (NTRS)

    Feldman, P. D.

    1975-01-01

    The possibility of meeting the requirements of the amps spectroscopic instrumentation by using a multi-element focal plane detector array in a conventional spectrograph mount was examined. The requirements of the detector array were determined from the optical design of the spectrometer which in turn depends on the desired level of resolution and sensitivity required. The choice of available detectors and their associated electronics and controls was surveyed, bearing in mind that the data collection rate from this system is so great that on-board processing and reduction of data are absolutely essential. Finally, parallel developments in instrumentation for imaging in astronomy were examined, both in the ultraviolet (for the Large Space Telescope as well as other rocket and satellite programs) and in the visible, to determine what progress in that area can have direct bearing on atmospheric spectroscopy.

  5. Performance Measurements On A 32X32 InSb-CID Detector Array For Astronomical Observations

    NASA Astrophysics Data System (ADS)

    Tiphene, D.; Lacombe, F.; Rouan, D.

    1989-01-01

    The use at liquid helium temperature of a InSb-CID detector array differs significantly from opera-tion at conditions usually adopted by the manufacturer (77K). In particular, the dark current behaviour hugely changes between the two temperatures. Only the tunnel current, independant of temperature conditions, is still active at 4.2K while the thermal-family currents vanish. We have studied the tunnel current of one InSb-MIS detector to determine its suitability to the low background conditions that will be met in the space experiment ISO. The search for the maximum integration time and the best quantum efficiency, the constraint about the photonic response linearity (especially at low photon flux), and the reduction of the readout noise constitute the main points of this study. Moreover, laboratory measurements showed secondary effects due to the detector (lag) or to the wiring (crosstalk). The CID array reactions to high energy radiations (Gamma rays) are finally discussed.

  6. Novel Usage for a Cosmic Ray Detector: Study of Lightning at Telescope Array

    NASA Astrophysics Data System (ADS)

    Belz, John; Okuda, Takeshi

    We describe observations performed at the Telescope Array Observatory in which "bursts" of air shower triggers of the surface detector occur in close temporal and spatial coincidence with lighting. These events appear to be consistent with other observations of high-energy particle showers produced by lightning. Telescope Array has the ability to reconstruct these showers using modified UHECR air shower reconstruction techniques, and thus determine the source of particles in the atmospheric breakdown. We describe new efforts to deploy lightning mapping detectors at the Telescope Array site which will enable further study of this phenomenon, along with enabling us to search for evidence of lightning strikes being "seeded" under certain atmospheric conditions by the passage of a UHECR air shower.

  7. Charge Sharing and Charge Loss in a Cadmium-Zinc-Telluride Fine-Pixel Detector Array

    NASA Technical Reports Server (NTRS)

    Gaskin, J. A.; Sharma, D. P.; Ramsey, B. D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a Cadmium-Zinc-Telluride (CZT) multi-pixel detector is ideal for hard x-ray astrophysical observation. As part of on-going research at MSFC (Marshall Space Flight Center) to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4x4 (750micron pitch), lmm thick pixel array and modeled these results using a Monte-Carlo simulation. This model was then used to predict the amount of charge sharing for a much finer pixel array (with a 300micron pitch). Future work will enable us to compare the simulated results for the finer array to measured values.

  8. A photon-counting photodiode array detector for far ultraviolet (FUV) astronomy

    NASA Technical Reports Server (NTRS)

    Hartig, G. F.; Moos, H. W.; Pembroke, R.; Bowers, C.

    1982-01-01

    A compact, stable, single-stage intensified photodiode array detector designed for photon-counting, far ultraviolet astronomy applications employs a saturable, 'C'-type MCP (Galileo S. MCP 25-25) to produce high gain pulses with a narrowly peaked pulse height distribution. The P-20 output phosphor exhibits a very short decay time, due to the high current density of the electron pulses. This intensifier is being coupled to a self-scanning linear photodiode array which has a fiber optic input window which allows direct, rigid mechanical coupling with minimal light loss. The array was scanned at a 250 KHz pixel rate. The detector exhibits more than adequate signal-to-noise ratio for pulse counting and event location.

  9. 3D Dose Verification Using Tomotherapy CT Detector Array

    SciTech Connect

    Sheng Ke; Jones, Ryan; Yang Wensha; Saraiya, Siddharth; Schneider, Bernard; Chen Quan; Sobering, Geoff; Olivera, Gustavo; Read, Paul

    2012-02-01

    Purpose: To evaluate a three-dimensional dose verification method based on the exit dose using the onboard detector of tomotherapy. Methods and Materials: The study included 347 treatment fractions from 24 patients, including 10 prostate, 5 head and neck (HN), and 9 spinal stereotactic body radiation therapy (SBRT) cases. Detector sonograms were retrieved and back-projected to calculate entrance fluence, which was then forward-projected on the CT images to calculate the verification dose, which was compared with ion chamber and film measurement in the QA plans and with the planning dose in patient plans. Results: Root mean square (RMS) errors of 2.0%, 2.2%, and 2.0% were observed comparing the dose verification (DV) and the ion chamber measured point dose in the phantom plans for HN, prostate, and spinal SBRT patients, respectively. When cumulative dose in the entire treatment is considered, for HN patients, the error of the mean dose to the planning target volume (PTV) varied from 1.47% to 5.62% with a RMS error of 3.55%. For prostate patients, the error of the mean dose to the prostate target volume varied from -5.11% to 3.29%, with a RMS error of 2.49%. The RMS error of maximum doses to the bladder and the rectum were 2.34% (-4.17% to 2.61%) and 2.64% (-4.54% to 3.94%), respectively. For the nine spinal SBRT patients, the RMS error of the minimum dose to the PTV was 2.43% (-5.39% to 2.48%). The RMS error of maximum dose to the spinal cord was 1.05% (-2.86% to 0.89%). Conclusions: An excellent agreement was observed between the measurement and the verification dose. In the patient treatments, the agreement in doses to the majority of PTVs and organs at risk is within 5% for the cumulative treatment course doses. The dosimetric error strongly depends on the error in multileaf collimator leaf opening time with a sensitivity correlating to the gantry rotation period.

  10. New detector array - the HRIBF Modular Total Absorption Spectrometer

    NASA Astrophysics Data System (ADS)

    Wolinska-Cichocka, Marzena; Rykaczewski, Krzysztof; Karny, Marek; Kuzniak, Aleksandra; Grzywacz, Robert; Rasco, Charlie; Miller, David; Gross, Carl J.; Johnson, Jim

    2011-10-01

    The construction of a new Modular Total Absorption Spectrometer (MTAS) at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory will be presented. The total absorption gamma spectra measured with MTAS will be used to derive a true beta-feeding pattern and resulting beta strength function for fission products. In particular, the measurements of decay heat released by radioactive nuclei produced in nuclear fuels at power reactors will be performed. MTAS is made up of 19 large NaI(Tl) crystals each encapsulated with a 0.8-mm-thick carbon fiber. There are also two 1-mm- thick Silicon Strip Detectors surrounding a moving tape collector that count beta-energy loss signals. The structure is shielded by more than 1-inch of lead around MTAS which reduces background radiation significantly. MTAS efficiency for full energy deposition of gamma ray approaches nearly 90% for 300 keV gammas and over 75% for a 5 MeV gamma transition. Research supported by the DOE Office of Nuclear Physics.

  11. Dynamic range considerations for EUV MAMA detectors. [Extreme UV Multianode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Illing, Rainer M. E.; Bybee, Richard L.; Timothy, J. G.

    1990-01-01

    The multianode microchannel array (MAMA) has been chosen as the detector for two instruments on the ESA/NASA Solar Heliospheric Observatory. The response of the MAMA to the two extreme types of solar spectra, disk and corona, have been modeled with a view toward evaluating dynamic range effects present. The method of MAMA operation is discussed, with emphasis given to modeling the effect of electron cloud charge spreading to several detector anodes and amplifiers (n-fold events). Representative synthetic EUV spectra have been created. The detector response to these spectra is modeled by dissecting the input photon radiation field across the detector array into contributions to the various amplifier channels. The results of this dissection are shown for spectral regions across the entire wavelength region of interest. These results are used to identify regions in which total array photon counting rate or individual amplifier rate may exceed the design limits. This allows the design or operational modes to be tailored to eliminate the problem areas.

  12. Large format array NIR detectors for future ESA astronomy missions: characterization and comparison

    NASA Astrophysics Data System (ADS)

    Gooding, David; Crouzet, Pierre-Elie; Duvet, Ludovic; Prod'homme, Thibaut; Smit, Hans; Ter Haar, Jörg; Blommaert, Sander; Visser, Ivo; Lemmel, Frederic; Heijnen, Jerko; Van Der Luijt, Cornelis; Butler, Bart; Beaufort, Thierry

    2016-08-01

    The Payload Technology Validation section in the Future Missions office of ESA's Science directorate at ESTEC provides testing support to present and future missions at different stages in their lifetime, from early technology developments to mission operation validation. In this framework, a test setup to characterize near-infrared (NIR) detectors has been created. In the context of the Astronomy Large Format Array for the near-infrared ("ALFA-N") technology development program, detectors from different suppliers are tested. We report on the characterization progress of the ALFA-N detectors, for which a series of rigorous tests have been performed on two different detectors; one provided by CEA/Leti-CEA/IRFU-SOFRADIR, France and the other by SELEX- UK/ATC, UK. Experimental techniques, the test bench and methods are presented. The conversion gain of two different detectors is measured using the photon transfer curve method. For a Leti LPE detector the persistence effect has been probed across a range of illumination levels to reveal a sharp linear increase of persistence below full-well and a plateauing beyond saturation. The same detector has been proton irradiated which has resulted in no significant dark current increase.

  13. Photoacoustic projection imaging using a 64-channel fiber optic detector array

    NASA Astrophysics Data System (ADS)

    Bauer-Marschallinger, Johannes; Felbermayer, Karoline; Bouchal, Klaus-Dieter; Veres, Istvan A.; Grün, Hubert; Burgholzer, Peter; Berer, Thomas

    2015-03-01

    In this work we present photoacoustic projection imaging with a 64-channel integrating line detector array, which average the pressure over cylindrical surfaces. For imaging, the line detectors are arranged parallel to each other on a cylindrical surface surrounding a specimen. Thereby, the three-dimensional imaging problem is reduced to a twodimensional problem, facilitating projection imaging. After acquisition of a dataset of pressure signals, a twodimensional photoacoustic projection image is reconstructed. The 64 channel line detector array is realized using optical fibers being part of interferometers. The parts of the interferometers used to detect the ultrasonic pressure waves consist of graded-index polymer-optical fibers (POFs), which exhibit better sensitivity than standard glass-optical fibers. Ultrasonic waves impinging on the POFs change the phase of light in the fiber-core due to the strain-optic effect. This phase shifts, representing the pressure signals, are demodulated using high-bandwidth balanced photo-detectors. The 64 detectors are optically multiplexed to 16 detection channels, thereby allowing fast imaging. Results are shown on a Rhodamine B dyed microsphere.

  14. A novel, SiPM-array-based, monolithic scintillator detector for PET

    NASA Astrophysics Data System (ADS)

    Schaart, Dennis R.; van Dam, Herman T.; Seifert, Stefan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Beekman, Freek J.

    2009-06-01

    Silicon photomultipliers (SiPMs) are of great interest to positron emission tomography (PET), as they enable new detector geometries, for e.g., depth-of-interaction (DOI) determination, are MR compatible, and offer faster response and higher gain than other solid-state photosensors such as avalanche photodiodes. Here we present a novel detector design with DOI correction, in which a position-sensitive SiPM array is used to read out a monolithic scintillator. Initial characterization of a prototype detector consisting of a 4 × 4 SiPM array coupled to either the front or back surface of a 13.2 mm × 13.2 mm × 10 mm LYSO:Ce3+ crystal shows that front-side readout results in significantly better performance than conventional back-side readout. Spatial resolutions <1.6 mm full-width-at-half-maximum (FWHM) were measured at the detector centre in response to an ~0.54 mm FWHM diameter test beam. Hardly any resolution losses were observed at angles of incidence up to 45°, demonstrating excellent DOI correction. About 14% FWHM energy resolution was obtained. The timing resolution, measured in coincidence with a BaF2 detector, equals 960 ps FWHM.

  15. A novel, SiPM-array-based, monolithic scintillator detector for PET.

    PubMed

    Schaart, Dennis R; van Dam, Herman T; Seifert, Stefan; Vinke, Ruud; Dendooven, Peter; Löhner, Herbert; Beekman, Freek J

    2009-06-07

    Silicon photomultipliers (SiPMs) are of great interest to positron emission tomography (PET), as they enable new detector geometries, for e.g., depth-of-interaction (DOI) determination, are MR compatible, and offer faster response and higher gain than other solid-state photosensors such as avalanche photodiodes. Here we present a novel detector design with DOI correction, in which a position-sensitive SiPM array is used to read out a monolithic scintillator. Initial characterization of a prototype detector consisting of a 4 x 4 SiPM array coupled to either the front or back surface of a 13.2 mm x 13.2 mm x 10 mm LYSO:Ce(3+) crystal shows that front-side readout results in significantly better performance than conventional back-side readout. Spatial resolutions <1.6 mm full-width-at-half-maximum (FWHM) were measured at the detector centre in response to an approximately 0.54 mm FWHM diameter test beam. Hardly any resolution losses were observed at angles of incidence up to 45 degrees , demonstrating excellent DOI correction. About 14% FWHM energy resolution was obtained. The timing resolution, measured in coincidence with a BaF(2) detector, equals 960 ps FWHM.

  16. X-ray Characterization of a Multichannel Smart-Pixel Array Detector

    SciTech Connect

    Ross, Steve; Haji-Sheikh, Michael; Huntington, Andrew; Kline, David; Lee, Adam; Li, Yuelin; Rhee, Jehyuk; Tarpley, Mary; Walko, Donald A.; Westberg, Gregg; Williams, George; Zou, Haifeng; Landahl, Eric

    2016-01-01

    The Voxtel VX-798 is a prototype X-ray pixel array detector (PAD) featuring a silicon sensor photodiode array of 48 x 48 pixels, each 130 mu m x 130 mu m x 520 mu m thick, coupled to a CMOS readout application specific integrated circuit (ASIC). The first synchrotron X-ray characterization of this detector is presented, and its ability to selectively count individual X-rays within two independent arrival time windows, a programmable energy range, and localized to a single pixel is demonstrated. During our first trial run at Argonne National Laboratory's Advance Photon Source, the detector achieved a 60 ns gating time and 700 eV full width at half-maximum energy resolution in agreement with design parameters. Each pixel of the PAD holds two independent digital counters, and the discriminator for X-ray energy features both an upper and lower threshold to window the energy of interest discarding unwanted background. This smart-pixel technology allows energy and time resolution to be set and optimized in software. It is found that the detector linearity follows an isolated dead-time model, implying that megahertz count rates should be possible in each pixel. Measurement of the line and point spread functions showed negligible spatial blurring. When combined with the timing structure of the synchrotron storage ring, it is demonstrated that the area detector can perform both picosecond time-resolved X-ray diffraction and fluorescence spectroscopy measurements.

  17. SU-E-T-524: In-Vivo Diode Dosimetry Proton Therapy Range Verification Validation Study for Pediatric CSI

    SciTech Connect

    Toltz, A; Seuntjens, J; Hoesl, M; Schuemann, J; Lu, H; Paganetti, H

    2015-06-15

    Purpose: With the aim of reducing acute esophageal radiation toxicity in pediatric patients receiving craniospinal irradiation (CSI), we investigated the implementation of an in-vivo, adaptive proton therapy range verification methodology. Simulation experiments and in-phantom measurements were conducted to validate the range verification technique for this clinical application. Methods: A silicon diode array system has been developed and experimentally tested in phantom for passively scattered proton beam range verification for a prostate treatment case by correlating properties of the detector signal to the water equivalent path length (WEPL). We propose to extend the methodology to verify range distal to the vertebral body for pediatric CSI cases by placing this small volume dosimeter in the esophagus of the anesthetized patient immediately prior to treatment. A set of calibration measurements was performed to establish a time signal to WEPL fit for a “scout” beam in a solid water phantom. Measurements are compared against Monte Carlo simulation in GEANT4 using the Tool for Particle Simulation (TOPAS). Results: Measurements with the diode array in a spread out Bragg peak of 14 cm modulation width and 15 cm range (177 MeV passively scattered beam) in solid water were successfully validated against proton fluence rate simulations in TOPAS. The resulting calibration curve allows for a sensitivity analysis of detector system response with dose rate in simulation and with individual diode position through simulation on patient CT data. Conclusion: Feasibility has been shown for the application of this range verification methodology to pediatric CSI. An in-vivo measurement to determine the WEPL to the inner surface of the esophagus will allow for personalized adjustment of the treatment plan to ensure sparing of the esophagus while confirming target coverage. A Toltz acknowledges partial support by the CREATE Medical Physics Research Training Network grant of the

  18. Lutetium oxyorthosilicate block detector readout by avalanche photodiode arrays for high resolution animal PET.

    PubMed

    Pichler, B J; Swann, B K; Rochelle, J; Nutt, R E; Cherry, S R; Siegel, S B

    2004-09-21

    Avalanche photodiodes (APDs) have proven to be useful as light detectors for high resolution positron emission tomography (PET). Their compactness makes these devices excellent candidates for replacing bulky photomultiplier tubes (PMTs) in PET systems where space limitations are an issue. The readout of densely packed, 10 x 10 lutetium oxyorthosilicate (LSO) block detectors (crystal size 2.0 x 2.0 x 12 mm3) with custom-built monolithic 3 x 3 APD arrays was investigated. The APDs had a 5 x 5 mm2 active surface and were arranged on a 6.25 mm pitch. The dead space on the edges of the array was 1.25 mm. The APDs were operated at a bias voltage of approximately 380 V for a gain of 100 and a dark current of 10 nA per APD. The standard deviation in gain between the APDs in the array ranged from 1.8 to 6.5% as the gain was varied from 50 to 108. A fast, low-noise, multi-channel charge sensitive preamplifier application-specific integrated circuit (ASIC) was developed for the APD readout. The amplifier had a rise time of 8 ns, a noise floor of 515 e- rms and a 9 e- pF(-1) noise slope. An acquired flood image showed that all 100 crystals from the block detector could be resolved. Timing measurements with single-channel LSO-APD detectors, as well as with the array, against a plastic scintillator and PMT assembly showed a time resolution of 1.2 ns and 2.5 ns, respectively. The energy resolution measured with a single 4.0 x 4.0 x 10 mm3 LSO crystal, wrapped in four-layer polytetrafluoroethylene (PTFE) tape and coupled with optical grease on a single APD of the array, yielded 15% (full width at half maximum, FWHM) at 511 keV. Stability tests over 9 months of operation showed that the APD arrays do not degrade appreciably. These results demonstrate the ability to decode densely packed LSO scintillation blocks with compact APD arrays. The good timing and energy resolution makes these detectors suitable for high resolution PET.

  19. Development of a Prototype for the Fluorescence Detector Array of Single-Pixel Telescopes

    NASA Astrophysics Data System (ADS)

    Fujii, T.; Malacari, M.; Bertaina, M.; Casolino, M.; Dawson, B.; Jiang, J.; Matalon, A.; Matthews, J. N.; Motloch, P.; Privitera, P.; Takizawa, Y.; Yamazaki, K.

    We present a concept for large-area, low-cost detection of ultra-high energy cosmic rays (UHECR) with a Fluorescence detector Array of Single-pixel Telescopes (FAST), addressing the requirements for the next generation of UHECR experiments. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. We report preliminary results of a FAST prototype installed at the Telescope Array site, consisting of a single 200 mm photo-multiplier tube at the focal plane of a 1 m2 Fresnel lens system taken from the prototype of the JEM-EUSO experiment.

  20. Detection and localization of particle-emitting sources with compound-eye inspired detector arrays

    NASA Astrophysics Data System (ADS)

    Liu, Zhi

    2007-08-01

    We develop methods to detect and localize particle-emitting sources using detector arrays that are inspired by biological compound eyes. The sources of interest may be optical, nuclear, or cosmic; they emit particles such as visible photons, neutrons, protons, or charged particles. Our results may have wide applications to artificial vision, which can be important in robotics (robot vision) or medicine (e.g., artificial eyes for the blind); security, where the detection of nuclear materials is needed; or astronomy. This dissertation consists of three parts. First, we detect a far-field particle source using two directional detector arrays: cubic and spherical. We propose a mean-difference test (MDT) detector, analyze its statistical performance, and show that the MDT has a number of advantages over the generalized likelihood- ratio test (GLRT). Second, we localize the source by proposing a novel biologically inspired detector array, whose configuration generalizes the compound eye of insects. This array combines the advantages of compound eyes (e.g., large field-of-view) and human eyes (e.g., high angular resolution). Based on a statistical model of the array measurements, we analyze the array performance by computing the Cramérao bound (CRB) on the error in estimating the source direction. We also derive lower bounds on the mean-square angular error (MSAE) of the source localization and investigate the MSAE of two source- direction estimators. Numerical examples, including the optimal array design, are presented to further illustrate the array performance. Third, we derive a statistical angular resolution limit (ARL) on resolving two closely spaced point sources in a three-dimensional frame, which is applicable to various measurement models (e.g., radar, sonar, or astronomy). Using the asymptotic analysis of the GLRT, we derive the ARL with constraints on the probabilities of false alarm and detection. Our results give explicit analytical expression for the ARL

  1. 20-element HgI[sub 2] energy dispersive x-ray array detector system

    SciTech Connect

    Iwanczyk, J.S.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. ); Hedman, B.; Hodgson, K.O. . Stanford Synchrotron Radiation Lab.); Patt, B.E. )

    1992-10-01

    This paper describes recent progress in the development of HgI[sub 2] energy dispersive x-ray arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20-element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K[sub alpha]) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken form diluted samples simulating proteins with nickel.

  2. Dosimetric characteristics of the novel 2D ionization chamber array OCTAVIUS Detector 1500

    SciTech Connect

    Stelljes, T. S. Looe, H. K.; Chofor, N.; Poppe, B.; Harmeyer, A.; Reuter, J.; Harder, D.

    2015-04-15

    Purpose: The dosimetric properties of the OCTAVIUS Detector 1500 (OD1500) ionization chamber array (PTW-Freiburg, Freiburg, Germany) have been investigated. A comparative study was carried out with the OCTAVIUS Detector 729 and OCTAVIUS Detector 1000 SRS arrays. Methods: The OD1500 array is an air vented ionization chamber array with 1405 detectors in a 27 × 27 cm{sup 2} measurement area arranged in a checkerboard pattern with a chamber-to-chamber distance of 10 mm in each row. A sampling step width of 5 mm can be achieved by merging two measurements shifted by 5 mm, thus fulfilling the Nyquist theorem for intensity modulated dose distributions. The stability, linearity, and dose per pulse dependence were investigated using a Semiflex 31013 chamber (PTW-Freiburg, Freiburg, Germany) as a reference detector. The effective depth of measurement was determined by measuring TPR curves with the array and a Roos chamber type 31004 (PTW-Freiburg, Freiburg, Germany). Comparative output factor measurements were performed with the array, the Semiflex 31010 ionization chamber and the Diode 60012 (both PTW-Freiburg, Freiburg, Germany). The energy dependence of the OD1500 was measured by comparing the array’s readings to those of a Semiflex 31010 ionization chamber for varying mean photon energies at the depth of measurement, applying to the Semiflex chamber readings the correction factor k{sub NR} for nonreference conditions. The Gaussian lateral dose response function of a single array detector was determined by searching the convolution kernel suitable to convert the slit beam profiles measured with a Diode 60012 into those measured with the array’s central chamber. An intensity modulated dose distribution measured with the array was verified by comparing a OD1500 measurement to TPS calculations and film measurements. Results: The stability and interchamber sensitivity variation of the OD1500 array were within ±0.2% and ±0.58%, respectively. Dose linearity was within 1

  3. The HgI sub 2 energy dispersive x-ray array detectors and minaturized processing electronics project

    SciTech Connect

    Iwanczyk, J.S.; Dorri, N.; Wang, M.; Szawlowski . Inst. of Physics); Patt, W.K. ); Hedman, B.; Hodgson, K.O. . Stanford Synchrotron Radiation Lab.)

    1990-04-01

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays for synchrotron radiation research and their associated miniaturized processing electronics. Deploying a 5 element HgI{sub 2} array detector under realistic operating conditions at SSRL, an energy resolution of 252 eV FWHM at 5.9 keV (Mn-K{alpha}) was obtained. The authors also report energy resolution and throughput measurements versus input count rate. The results from the HgI{sub 2} system are then compared to those obtained under identical conditions from a commercial 13 element Ge detector array.

  4. Development of an 8× 8 CPW Microwave Kinetic Inductance Detector (MKID) Array at 0.35 THz

    NASA Astrophysics Data System (ADS)

    Li, Jing; Yang, Jin-Ping; Lin, Zhen-Hui; Liu, Dong; Shi, Sheng-Cai; Mima, S.; Furukawa, N.; Otani, C.

    2016-07-01

    Microwave kinetic inductance detectors (MKIDs) are promising for THz direct detector arrays of large size, particularly with simple frequency-division multiplexing. Purple Mountain Observatory is developing a terahertz superconducting imaging array (TeSIA) for the DATE5 telescope to be constructed at Dome A, Antarctica. Here we report on the development of a prototype array for the TeSIA, namely an 8× 8 CPW MKID array at 0.35 THz. The resonance frequencies of the MKIDs span the 4-5.575 GHz band with an interval of 25 MHz. Each detector is integrated with a twin-slot antenna centered at 0.5 THz and with a relative bandwidth of 10 %, while the whole MKID array with a micro-lens array. Detailed design and measurement results will be presented.

  5. Continuous-wave terahertz digital holographic tomography with a pyroelectric array detector

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, Dayong; Zhou, Xun; Rong, Lu; Li, Zeyu; Li, Lei; Min, Wan; Huang, Haochong; Wang, Yunxin

    2016-05-01

    Terahertz computed tomography makes use of the penetrability of terahertz radiation and obtains three-dimensional (3-D) object projection data. Continuous-wave terahertz digital holographic tomography with a pyroelectric array detector is presented. Compared with scanning terahertz computed tomography, a pyroelectric array detector can obtain a large quantity of projection data in a short time. To obtain a 3-D image, in-line digital holograms of the object are recorded from various directions and reconstructed to obtain two-dimensional (2-D) projection data; then 2-D cross-sectional images and 3-D images of the internal structure of the object are obtained by the filtered back projection algorithm. The presented system can rapidly reconstruct the 3-D object and reveals the internal 3-D structure of the object. A 3-D reconstruction of a polyethylene straw is presented with a 6% error in retrieved diameter.

  6. A surface micromachined thermopile detector array with an interference-based absorber

    NASA Astrophysics Data System (ADS)

    Wu, H.; Emadi, A.; Sarro, P. M.; de Graaf, G.; Wolffenbuttel, R. F.

    2011-07-01

    A thermo-electric (TE) infrared detector array composed of 23 thermopiles, each with 5 thermocouples on a suspended beam of 650 × 36 µm2 dimensions, has been fabricated in a CMOS-compatible MEMS process. The array is used for realization of an IR micro-spectrometer in the 1-5 µm spectral range. Interference filter-based IR absorbers using titanium/aluminum layers with a silicon carbide cavity layer have been designed, fabricated and validated. These thin film stacks are more suitable for the subsequent processes as compared to conventional techniques. The silicon carbide layer is also used for device protection. The TE detector with an interference filter-based absorber features a sensitivity of 294 V W-1 in the 2.15 µm wavelength range and a thermal time constant of 4.85 ms in vacuum.

  7. Underground water Cherenkov muon detector array with the Tibet air shower array for gamma-ray astronomy in the 100 TeV region

    NASA Astrophysics Data System (ADS)

    Amenomori, M.; Ayabe, S.; Bi, X. J.; Chen, D.; Cui, S. W.; Danzengluobu; Ding, L. K.; Ding, X. H.; Feng, C. F.; Feng, Zhaoyang; Feng, Z. Y.; Gao, X. Y.; Geng, Q. X.; Guo, H. W.; He, H. H.; He, M.; Hibino, K.; Hotta, N.; Hu, Haibing; Hu, H. B.; Huang, J.; Huang, Q.; Jia, H. Y.; Kajino, F.; Kasahara, K.; Katayose, Y.; Kato, C.; Kawata, K.; Labaciren; Le, G. M.; Li, A. F.; Li, J. Y.; Lu, H.; Lu, S. L.; Meng, X. R.; Mizutani, K.; Mu, J.; Munakata, K.; Nagai, A.; Nanjo, H.; Nishizawa, M.; Ohnishi, M.; Ohta, I.; Onuma, H.; Ouchi, T.; Ozawa, S.; Ren, J. R.; Saito, T.; Saito, T. Y.; Sakata, M.; Sako, T. K.; Sasaki, T.; Shibata, M.; Shiomi, A.; Shirai, T.; Sugimoto, H.; Takita, M.; Tan, Y. H.; Tateyama, N.; Torii, S.; Tsuchiya, H.; Udo, S.; Wang, B.; Wang, H.; Wang, X.; Wang, Y. G.; Wu, H. R.; Xue, L.; Yamamoto, Y.; Yan, C. T.; Yang, X. C.; Yasue, S.; Ye, Z. H.; Yu, G. C.; Yuan, A. F.; Yuda, T.; Zhang, H. M.; Zhang, J. L.; Zhang, N. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Yi; Zhaxisangzhu; Zhou, X. X.

    2007-06-01

    We propose to build a large water-Cherenkov-type muon-detector array (Tibet MD array) around the 37 000 m2 Tibet air shower array (Tibet AS array) already constructed at 4300 m above sea level in Tibet, China. Each muon detector is a waterproof concrete pool, 6 m wide × 6 m long × 1.5 m deep in size, equipped with a 20 inch-in-diameter PMT. The Tibet MD array consists of 240 muon detectors set up 2.5 m underground. Its total effective area will be 8640 m2 for muon detection. The Tibet MD array will significantly improve gamma-ray sensitivity of the Tibet AS array in the 100 TeV region (10 1000 TeV) by means of gamma/hadron separation based on counting the number of muons accompanying an air shower. The Tibet AS+MD array will have the sensitivity to gamma rays in the 100 TeV region by an order of magnitude better than any other previous existing detectors in the world.

  8. Quantum efficiency performances of the NIR European Large Format Array detectors tested at ESTEC

    NASA Astrophysics Data System (ADS)

    Crouzet, P.-E.; Duvet, L.; de Wit, F.; Beaufort, T.; Blommaert, S.; Butler, B.; Van Duinkerken, G.; ter Haar, J.; Heijnen, J.; van der Luijt, K.; Smit, H.

    2015-10-01

    Publisher's Note: This paper, originally published on 10/12/2015, was replaced with a corrected/revised version on 10/23/2015. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. The Payload Technology Validation Section (SRE-FV) at ESTEC has the goal to validate new technology for future or on-going mission. In this framework, a test set up to characterize the quantum efficiency of near-infrared (NIR) detectors has been created. In the context of the NIR European Large Format Array ("LFA"), 3 deliverables detectors coming from SELEX-UK/ATC (UK) on one side, and CEA/LETI- CEA/IRFU-SOFRADIR (FR) on the other side were characterized. The quantum efficiency of an HAWAII-2RG detector from Teledyne was as well measured. The capability to compare on the same setup detectors from different manufacturers is a unique asset for the future mission preparation office. This publication will present the quantum efficiency results of a HAWAII-2RG detector from Teledyne with a 2.5um cut off compared to the LFA European detectors prototypes developed independently by SELEX-UK/ATC (UK) on one side, and CEA/LETI- CEA/IRFU-SOFRADIR (FR) on the other side.

  9. Investigation of Very Fast Light Detectors: Silicon Photomultiplier and Micro PMT for a Cosmic Ray Array

    NASA Astrophysics Data System (ADS)

    Cervantes, Omar; Reyes, Liliana; Hooks, Tyler; Perez, Luis; Ritt, Stefan

    2016-03-01

    To construct a cosmic detector array using 4 scintillation detectors, we investigated 2 recent light sensor technologies from Hamamatsu, as possible readout detectors. First, we investigated several homemade versions of the multipixel photon counter (MPPC) light sensors. These detectors were either biased with internal or external high voltage power supplies. We made extensive measurements to confirm for the coincidence of the MPPC devices. Each sensor is coupled to a wavelength shifting fiber (WSF) that is embedded along a plastic scintillator sheet (30cmx60cmx1/4''). Using energetic cosmic rays, we evaluated several of these homemade detector modules placed above one another in a light proof enclosure. Next, we assembled 2 miniaturized micro photomultiplier (micro PMT), a device recently marketed by Hamamatsu. These sensors showed very fast response times. With 3 WSF embedded in scintillator sheets, we performed coincidence experiments. The detector waveforms were captured using the 5GS/sec domino ring sampler, the DRS4 and our workflow using the CERN PAW package and data analysis results would be presented. Title V Grant.

  10. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz Detector Array of Bolometric Polarimeters

    NASA Technical Reports Server (NTRS)

    Appel, John W.; Ali, Aamir; Amiri, Mandana; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Kogut, Alan J..; Miller, Nathan; Moseley, Samuel H.; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  11. AFRL Nanotechnology Initiative: Hybrid Nanomaterials in Photonic Crystal Cavities for Multi-Spectral Infrared Detector Arrays

    DTIC Science & Technology

    2010-03-31

    INITIATIVE) HYBRID NANOMATERIALS IN PHOTONIC CRYSTAL CAVITIES FOR MULTI -SPECTRAL INFRARED DETECTOR ARRAYS 5b. GRANT NUMBER F A9550-06-1-0482 5c...IR) photodetector using hybrid nanornaterials in photonic crystal (PC) cavities for enhanced absorption at selected wavelengths. The simultaneous...infrared photodetection, quantum dots, photonic crystal cavities, matrix-assisted pulsed laser evaporation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  12. Lung counting: comparison of detector performance with a four detector array that has either metal or carbon fibre end caps, and the effect on mda calculation.

    PubMed

    Ahmed, Asm Sabbir; Hauck, Barry; Kramer, Gary H

    2012-08-01

    This study described the performance of an array of high-purity Germanium detectors, designed with two different end cap materials-steel and carbon fibre. The advantages and disadvantages of using this detector type in the estimation of the minimum detectable activity (MDA) for different energy peaks of isotope (152)Eu were illustrated. A Monte Carlo model was developed to study the detection efficiency for the detector array. A voxelised Lawrence Livermore torso phantom, equipped with lung, chest plates and overlay plates, was used to mimic a typical lung counting protocol with the array of detectors. The lung of the phantom simulated the volumetric source organ. A significantly low MDA was estimated for energy peaks at 40 keV and at a chest wall thickness of 6.64 cm.

  13. Performance of the Versatile Array of Neutron Detectors at Low Energy (VANDLE)

    SciTech Connect

    Peters, W. A.; Ilyushkin, S.; Madurga, M.; Matei, C.; Paulauskas, S. V.; Grzywacz, R. K.; Bardayan, D. W.; Brune, C. R.; Allen, J.; Allen, J. M.; Bergstrom, Z.; Blackmon, J.; Brewer, N. T.; Cizewski, J. A.; Copp, P.; Howard, M. E.; Ikeyama, R.; Kozub, R. L.; Manning, B.; Massey, T. N.; Matos, M.; Merino, E.; O'Malley, P. D.; Raiola, F.; Reingold, C. S.; Sarazin, F.; Spassova, I.; Taylor, S.; Walter, D.

    2016-08-26

    The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new, highly efficient plastic-scintillator array constructed for decay and transfer reaction experimental setups that require neutron detection. The versatile and modular design allows for customizable experimental setups including beta-delayed neutron spectroscopy and (d,n) transfer reactions in normal and inverse kinematics. The neutron energy and prompt-photon discrimination is determined through the time of flight technique. Fully digital data acquisition electronics and integrated triggering logic enables some VANDLE modules to achieve an intrinsic efficiency over 70% for 300-keV neutrons, measured through two different methods. A custom Geant4 simulation models aspects of the detector array and the experimental setups to determine efficiency and detector response. Lastly, a low detection threshold, due to the trigger logic and digitizing data acquisition, allowed us to measure the light-yield response curve from elastically scattered carbon nuclei inside the scintillating plastic from incident neutrons with kinetic energies below 2 MeV.

  14. Performance of the Versatile Array of Neutron Detectors at Low Energy (VANDLE)

    NASA Astrophysics Data System (ADS)

    Peters, W. A.; Ilyushkin, S.; Madurga, M.; Matei, C.; Paulauskas, S. V.; Grzywacz, R. K.; Bardayan, D. W.; Brune, C. R.; Allen, J.; Allen, J. M.; Bergstrom, Z.; Blackmon, J.; Brewer, N. T.; Cizewski, J. A.; Copp, P.; Howard, M. E.; Ikeyama, R.; Kozub, R. L.; Manning, B.; Massey, T. N.; Matos, M.; Merino, E.; O'Malley, P. D.; Raiola, F.; Reingold, C. S.; Sarazin, F.; Spassova, I.; Taylor, S.; Walter, D.

    2016-11-01

    The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new, highly efficient plastic-scintillator array constructed for decay and transfer reaction experimental setups that require neutron detection. The versatile and modular design allows for customizable experimental setups including beta-delayed neutron spectroscopy and (d,n) transfer reactions in normal and inverse kinematics. The neutron energy and prompt-photon discrimination is determined through the time of flight technique. Fully digital data acquisition electronics and integrated triggering logic enables some VANDLE modules to achieve an intrinsic efficiency over 70% for 300-keV neutrons, measured through two different methods. A custom GEANT4 simulation models aspects of the detector array and the experimental setups to determine efficiency and detector response. A low detection threshold, due to the trigger logic and digitizing data acquisition, allowed us to measure the light-yield response curve from elastically scattered carbon nuclei inside the scintillating plastic from incident neutrons with kinetic energies below 2 MeV.

  15. Performance of the Versatile Array of Neutron Detectors at Low Energy (VANDLE)

    DOE PAGES

    Peters, W. A.; Ilyushkin, S.; Madurga, M.; ...

    2016-08-26

    The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new, highly efficient plastic-scintillator array constructed for decay and transfer reaction experimental setups that require neutron detection. The versatile and modular design allows for customizable experimental setups including beta-delayed neutron spectroscopy and (d,n) transfer reactions in normal and inverse kinematics. The neutron energy and prompt-photon discrimination is determined through the time of flight technique. Fully digital data acquisition electronics and integrated triggering logic enables some VANDLE modules to achieve an intrinsic efficiency over 70% for 300-keV neutrons, measured through two different methods. A custom Geant4 simulation models aspectsmore » of the detector array and the experimental setups to determine efficiency and detector response. Lastly, a low detection threshold, due to the trigger logic and digitizing data acquisition, allowed us to measure the light-yield response curve from elastically scattered carbon nuclei inside the scintillating plastic from incident neutrons with kinetic energies below 2 MeV.« less

  16. A space qualified thermal imaging system using a Pt Si detector array

    NASA Technical Reports Server (NTRS)

    Astheimer, Robert W.

    1989-01-01

    EDO Corporation, Barnes Engineering Division designed and constructed a high resolution thermal imaging system on contract to Lockheed for use in the SDI Star Lab. This employs a Pt Si CCD array which is sensitive in the spectral range of 3 to 5 microns. Star Lab will be flown in the Shuttle bay and consists basically of a large, reflecting, tracking telescope with associated sensors and electronics. The thermal imaging system is designed to operate in the focal plane of this telescope. The configuration of the system is illustrated. The telescope provides a collimated beam output which is focussed onto the detector array by a silicon objective lens. The detector array subtends a field of view of 1.6 degrees x 1.22 degrees. A beam switching mirror permits bypassing the large telescope to give a field of 4 degrees x 3 degrees. Two 8 position filter wheels are provided, and background radiation is minimized by Narcissus mirrors. The detector is cooled with a Joule-Thompson cryostat fed from a high pressure supply tank. This was selected instead of a more convenient closed-cycle system because of concern with vibration. The latter may couple into the extremely critical Starlab tracking telescope. The electronics produce a digitized video signal for recording. Offset and responsivity correction factors are stored for all pixels and these corrections are made to the digitized output in real time.

  17. Development of mercuric iodide energy dispersive x-ray array detectors

    SciTech Connect

    Iwanczyk, J.S.; Warburton, W.K.; Dabrowski, A.J.; Hedman, B.; Hodgson, K.O.; Patt, B.E.

    1988-02-01

    There are various areas of synchrotron radiation research particularly Extended X-Ray Absorption Fine Structure (EXAFS) on dilute solutions and anomalous scattering, which would strongly benefit from the availability of energy dispersive detector arrays with high energy resolution and good spatial resolution. The goal of this development project is to produce high energy resolution mercuric iodide (HgI/sub 2/) detector sub-modules, consisting of several elements. These sub-modules can later be grouped into larger arrays of 100-400 elements. A prototype 5 element HgI/sub 2/ array detector was constructed and tested. Dimensions of each element were 7.3 mm x 0.7 mm. An energy resolution of 335 eV (FWHM) for Mn0K..cap alpha.. at 5.9 keV has been measured. The novel fiber-optic pulsed light feedback has been introduced into the charge preamplifiers in order to minimize electronic crosstalk between channels.

  18. Local polarization phenomena in In-doped CdTe x-ray detector arrays

    SciTech Connect

    Sato, Toshiyuki; Sato, Kenji; Ishida, Shinichiro; Kiri, Motosada; Hirooka, Megumi; Yamada, Masayoshi; Kanamori, Hitoshi

    1995-10-01

    Local polarization phenomena have been studied in detector arrays with the detector element size of 500 {micro}m x 500 {micro}m, which are fabricated from high-resistivity In-doped CdTe crystals grown by the vertical Bridgman technique. It has been found for the first time that a polarization effect, which is characterized by a progressive decrease of the pulse counting rate with increasing photon fluence, strongly depends on the detector elements, that is, the portion of crystals used. The influence of several parameters, such as the applied electric field strength, time, and temperature, on this local polarization effect is also investigated. From the photoluminescence measurements of the inhomogeneity of In dopant, it is concluded that the local polarization effect observed here originates from a deep level associated with In dopant in CdTe crystals.

  19. a Cosmic Ray Detector Array for Schools in the Cambridge Region

    NASA Astrophysics Data System (ADS)

    Wotton, S. A.; Goodrick, M. J.; Hommels, B.; Parker, M. A.

    2011-06-01

    Particle physics, astrophysics and cosmology are areas of research that have captured the imagination of the general public in recent years. By giving school students first-hand experience of building and operating a particle detector and the analysis of the data in a collaborative environment we anticipate that they will gain a deeper insight into the many and diverse facets of experimental particle physics. Cosmic rays provide a readily available source of high energy particles and other projects have already exploited this in building arrays of cosmic ray detectors located in schools and linked together via the internet. We aim to extend this concept by creating our own network of detectors in our region with a particular emphasis on hands-on involvement by school students in the partner schools. This talk outlines our plans towards the implementation of this project and our wider goals of integrating our local network with other projects both nationally and internationally.

  20. Charge-coupled-device/fiberoptic taper array x-ray detector for protein crystallography

    SciTech Connect

    Naday, I.; Ross, S.; Westbrook, E.M.; Zentai, G.

    1997-12-31

    A large area, charge-couple-device (CCD) based fiberoptic taper array detector (APS-1) has been installed at the insertion-device beamline of the Structural Biology Center at the ANL Advanced Photon Source. The detector is used in protein crystallography diffraction experiments, where the objective is to measure the position and intensity of X-ray Bragg peaks in diffraction images. Large imaging area, very high spatial resolution, high X-ray sensitivity, good detective quantum efficiency, low noise, wide dynamic range, excellent stability and short readout time are all fundamental requirements in this application. The APS-1 detector converts the two-dimensional X-ray patterns to a visible light images by a thin layer of X-ray sensitive phosphor. The phosphor coating is directly deposited on the large ends of nine fiberoptic tapers arranged in a 3 x 3 array. Nine, thermoelectrically cooled 1,024 x 1,024 pixel CCD`s image the patterns, demagnified by the tapers. After geometrical and uniformity corrections, the nine areas give a continuous image of the detector face with virtually no gaps between the individual tapers. The 18 parallel analog signal-processing channels and analog-to-digital converters assure short readout time and low readout noise.

  1. Charge-coupled-device/fiberoptic taper array X-ray detector for protein crystallography

    SciTech Connect

    Naday, I.; Ross, S.; Westbrook, E.M.; Zentai, G.

    1997-03-01

    A large area, charge-couple-device (CCD) based fiberoptic taper array detector (APS-1) has been installed at the insertion-device beamline of the Structural Biology Center at the ANL Advanced Photon Source. The detector is used in protein crystallography diffraction experiments, where the objective is to measure the position and intensity of X-ray Bragg peaks in diffraction images. Large imaging area, very high spatial resolution, high X-ray sensitivity, good detective quantum efficiency, low noise, wide dynamic range, excellent stability and short readout time are all fundamental requirements in this application. The APS-1 detector converts the two-dimensional X-ray patterns to a visible light images by a thin layer of X-ray sensitive phosphor. The phosphor coating is directly deposited on the large ends of nine fiberoptic tapers arranged in a 3x3 array. Nine, thermoelectrically cooled 1024 x 1024 pixel CCD`s image the patterns, demagnified by the tapers. After geometrical and uniformity corrections, the nine areas give a continuous image of the detector face with virtually no gaps between the individual tapers. The 18 parallel analog signal-processing channels and analog-to-digital converters assure short readout time and low readout noise.

  2. Studies of Nuclear Structure using Radioactive Decay and a Large Array of Compton Suppressed Ge Detectors

    NASA Astrophysics Data System (ADS)

    Wood, John L.

    2000-11-01

    Radioactive decay has long played a role in contributing to the elucidation of nuclear structure. However compared to in-beam gamma-ray spectroscopy, which has been combined with the extraordinary power of multi-detector arrays, radioactive decay scheme studies have been carried out usually with rather modest detector set-ups (two detectors, no Compton suppression). An extensive program to rectify this situation has been initiated using the "8-PI spectrometer"[1]. This is an array of 20 Compton-suppressed Ge detectors with exceptional stability and peak-to-total ratio. Experiments performed[2] recently at Lawrence Berkeley Laboratory, to better characterize nuclear deformation properties and the onset of deformation in nuclei, will be described. Future plans for the study of nuclei far from beta stability at the TRIUMF/ISAC Facility using the 8-PI spectrometer will also be outlined. [1] J.P.Martin et al., Nucl.Instr.Meth. A 257, 301 (1987). [2] See, e.g., W.D.Kulp et al. Bull.Am.Phys.Soc. 44, 63 (1999); W.D.Kulp et al., ibid., Williamsburg Meeting, Oct 4-7 (2000).

  3. Development of arrays of Silicon Drift Detectors and readout ASIC for the SIDDHARTA experiment

    NASA Astrophysics Data System (ADS)

    Quaglia, R.; Schembari, F.; Bellotti, G.; Butt, A. D.; Fiorini, C.; Bombelli, L.; Giacomini, G.; Ficorella, F.; Piemonte, C.; Zorzi, N.

    2016-07-01

    This work deals with the development of new Silicon Drift Detectors (SDDs) and readout electronics for the upgrade of the SIDDHARTA experiment. The detector is based on a SDDs array organized in a 4×2 format with each SDD square shaped with 64 mm2 (8×8) active area. The total active area of the array is therefore 32×16 mm2 while the total area of the detector (including 1 mm border dead area) is 34 × 18mm2. The SIDDHARTA apparatus requires 48 of these modules that are designed and manufactured by Fondazione Bruno Kessler (FBK). The readout electronics is composed by CMOS preamplifiers (CUBEs) and by the new SFERA (SDDs Front-End Readout ASIC) circuit. SFERA is a 16-channels readout ASIC designed in a 0.35 μm CMOS technology, which features in each single readout channel a high order shaping amplifier (9th order Semi-Gaussian complex-conjugate poles) and a high efficiency pile-up rejection logic. The outputs of the channels are connected to an analog multiplexer for the external analog to digital conversion. An on-chip 12-bit SAR ADC is also included. Preliminary measurements of the detectors in the single SDD format are reported. Also measurements of low X-ray energies are reported in order to prove the possible extension to the soft X-ray range.

  4. Charge-coupled device/fiber optic taper array x-ray detector for protein crystallography

    SciTech Connect

    Naday, I.; Ross, S.; Westbrook, E.M.; Zentai, G.

    1998-04-01

    A large area charge-coupled device (CCD) based fiber optic taper array detector (APS-1) is installed at the insertion-device beamline of the Structural Biology Center at the Argonne Advanced Photon Source x-ray synchrotron. The detector is used in protein crystallography diffraction experiments, where the objective is to measure the position and intensity of x-ray Bragg peaks in diffraction images. Large imaging area, very high spatial resolution, high x-ray sensitivity, good detective quantum efficiency, low noise, wide dynamic range, excellent stability and short readout time are all fundamental requirements in this application. The APS-1 detector converts the 2-D x-ray patterns to visible light images by a thin layer of x-ray sensitive phosphor. The phosphor coating is directly deposited on the large ends of nine fiber optic tapers arranged in a 3{times}3 array. Nine, thermoelectrically cooled 1024{times}1024pixel CCDs image the patterns, demagnified by the tapers. After geometrical and uniformity corrections, the nine areas give a continuous image of the detector face with virtually no gaps between the individual tapers. The 18 parallel analog signal-processing channels and analog-to-digital converters ensure short readout time and low readout noise. We discuss the design and measured performance of the detector. {copyright} {ital 1998 Society of Photo-Optical Instrumentation Engineers.}{ital Key words:} charge-coupled device; fiber optic taper; x-ray diffraction; crystallography; imaging detector. {copyright} {ital 1998} {ital Society of Photo-Optical Instrumentation Engineers}

  5. Mercuric iodide room-temperature array detectors for gamma-ray imaging

    SciTech Connect

    Patt, B.

    1994-11-15

    Significant progress has been made recently in the development of mercuric iodide detector arrays for gamma-ray imaging, making real the possibility of constructing high-performance small, light-weight, portable gamma-ray imaging systems. New techniques have been applied in detector fabrication and then low noise electronics which have produced pixel arrays with high-energy resolution, high spatial resolution, high gamma stopping efficiency. Measurements of the energy resolution capability have been made on a 19-element protypical array. Pixel energy resolutions of 2.98% fwhm and 3.88% fwhm were obtained at 59 keV (241-Am) and 140-keV (99m-Tc), respectively. The pixel spectra for a 14-element section of the data is shown together with the composition of the overlapped individual pixel spectra. These techniques are now being applied to fabricate much larger arrays with thousands of pixels. Extension of these principles to imaging scenarios involving gamma-ray energies up to several hundred keV is also possible. This would enable imaging of the 208 keV and 375-414 keV 239-Pu and 240-Pu structures, as well as the 186 keV line of 235-U.

  6. Performance of charge-injection-device infrared detector arrays at low and moderate backgrounds

    NASA Technical Reports Server (NTRS)

    Mckelvey, M. E.; Mccreight, C. R.; Goebel, J. H.; Reeves, A. A.

    1985-01-01

    Three 2 x 64 element charge injection device infrared detector arrays were tested at low and moderate background to evaluate their usefulness for space based astronomical observations. Testing was conducted both in the laboratory and in ground based telescope observations. The devices showed an average readout noise level below 200 equivalent electrons, a peak responsivity of 4 A/W, and a noise equivalent power of 3x10 sq root of W/Hz. Array well capacity was measured to be significantly smaller than predicted. The measured sensitivity, which compares well with that of nonintegrating discrete extrinsic silicon photoconductors, shows these arrays to be useful for certain astronomical observations. However, the measured readout efficiency and frequency response represent serious limitations in low background applications.

  7. Experimental study of double-{beta} decay modes using a CdZnTe detector array

    SciTech Connect

    Dawson, J. V.; Goessling, C.; Koettig, T.; Muenstermann, D.; Rajek, S.; Schulz, O.; Janutta, B.; Zuber, K.; Junker, M.; Reeve, C.; Wilson, J. R.

    2009-08-15

    An array of sixteen 1 cm{sup 3} CdZnTe semiconductor detectors was operated at the Gran Sasso Underground Laboratory (LNGS) to further investigate the feasibility of double-{beta} decay searches with such devices. As one of the double-{beta} decay experiments with the highest granularity the 4x4 array accumulated an overall exposure of 18 kg days. The setup and performance of the array is described. Half-life limits for various double-{beta} decay modes of Cd, Zn, and Te isotopes are obtained. No signal has been found, but several limits beyond 10{sup 20} years have been performed. They are an order of magnitude better than those obtained with this technology before and comparable to most other experimental approaches for the isotopes under investigation. An improved limit for the {beta}{sup +}/EC decay of {sup 120}Te is given.

  8. Microelectrode Arrays with Overlapped Diffusion Layers as Electroanalytical Detectors: Theory and Basic Applications

    PubMed Central

    Tomčík, Peter

    2013-01-01

    This contribution contains a survey of basic literature dealing with arrays of microelectrodes with overlapping diffusion layers as prospective tools in contemporary electrochemistry. Photolithographic thin layer technology allows the fabrication of sensors of micrometric dimensions separated with a very small gap. This fact allows the diffusion layers of single microelectrodes to overlap as members of the array. Various basic types of microelectrode arrays with interacting diffusion layers are described and their analytical abilities are accented. Theoretical approaches to diffusion layer overlapping and the consequences of close constitution effects such as collection efficiency and redox cycling are discussed. Examples of basis applications in electroanalytical chemistry such as amperometric detectors in HPLC and substitutional stripping voltammetry are also given. PMID:24152927

  9. NORSAR Final Scientific Report Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration

    SciTech Connect

    Gibbons, S J; Ringdal, F; Harris, D B

    2009-04-16

    Correlation detection is a relatively new approach in seismology that offers significant advantages in increased sensitivity and event screening over standard energy detection algorithms. The basic concept is that a representative event waveform is used as a template (i.e. matched filter) that is correlated against a continuous, possibly multichannel, data stream to detect new occurrences of that same signal. These algorithms are therefore effective at detecting repeating events, such as explosions and aftershocks at a specific location. This final report summarizes the results of a three-year cooperative project undertaken by NORSAR and Lawrence Livermore National Laboratory. The overall objective has been to develop and test a new advanced, automatic approach to seismic detection using waveform correlation. The principal goal is to develop an adaptive processing algorithm. By this we mean that the detector is initiated using a basic set of reference ('master') events to be used in the correlation process, and then an automatic algorithm is applied successively to provide improved performance by extending the set of master events selectively and strategically. These additional master events are generated by an independent, conventional detection system. A periodic analyst review will then be applied to verify the performance and, if necessary, adjust and consolidate the master event set. A primary focus of this project has been the application of waveform correlation techniques to seismic arrays. The basic procedure is to perform correlation on the individual channels, and then stack the correlation traces using zero-delay beam forming. Array methods such as frequency-wavenumber analysis can be applied to this set of correlation traces to help guarantee the validity of detections and lower the detection threshold. In principle, the deployment of correlation detectors against seismically active regions could involve very large numbers of very specific detectors. To

  10. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    PubMed Central

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-01

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed. PMID:26917125

  11. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    DOE PAGES

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; ...

    2016-01-28

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses atmore » megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. Lastly, we detail the characteristics, operation, testing and application of the detector.« less

  12. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    SciTech Connect

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-28

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. Lastly, we detail the characteristics, operation, testing and application of the detector.

  13. Three-dimensional modeling and inversion of x-ray pinhole detector arrays

    SciTech Connect

    Tritz, K.; Stutman, D.; Delgado-Aparicio, L.; Finkenthal, M.

    2006-10-15

    X-ray pinhole detectors are a common and useful diagnostic for high temperature and fusion-grade plasmas. While the measurements from such diagnostics are line integrated, local emission can be recovered by inverting or modeling the data using varying assumptions including toroidal symmetry, flux surface isoemissivity, and one-dimensional (1D) chordal lines of sight. This last assumption is often valid when the structure sizes and gradient scale lengths of interest are much larger than the spatial resolution of the detector elements. However, x-ray measurements of, for example, the strong gradients in the H-mode pedestal may require a full three-dimensional (3D) treatment of the detector geometry when the emission of the plasma has a significant variation within the field of view, especially in a high-triangularity, low aspect ratio plasma. Modeling of a high spatial resolution tangential edge array for NSTX has shown that a proper 3D treatment can improve the effective spatial resolution of the detector by 10%-40% depending on the modeled signal-to-noise ratio and gradient scale length. Results from a general treatment of arbitrary detector geometry will provide a guideline for the amount of systematic error that can be expected by a 1D versus 3D field of view analysis.

  14. Real-time scintillation array dosimetry for radiotherapy: The advantages of photomultiplier detectors

    SciTech Connect

    Liu, Paul Z. Y.; Suchowerska, Natalka; Abolfathi, Peter; McKenzie, David R.

    2012-04-15

    Purpose: In this paper, a photomultiplier tube (PMT) array dosimetry system has been developed and tested for the real-time readout of multiple scintillation signals from fiber optic dosimeters. It provides array dosimetry with the advantages in sensitivity provided by a PMT, but without the need for a separate PMT for each detector element. Methods: The PMT array system consisted of a multianode PMT, a multichannel data acquisition system, housing and optic fiber connections suitable for clinical use. The reproducibility, channel uniformity, channel crosstalk, acquisition speed, and sensitivity of the PMT array were quantified using a constant light source. Its performance was compared to other readout systems used in scintillation dosimetry. An in vivo HDR brachytherapy treatment was used as an example of a clinical application of the dosimetry system to the measurement of dose at multiple sites in the rectum. The PMT array system was also tested in the pulsed beam of a linear accelerator to test its response speed and its application with two separate methods of Cerenkov background removal. Results: The PMT array dosimetry system was highly reproducible with a measurement uncertainty of 0.13% for a 10 s acquisition period. Optical crosstalk between neighboring channels was accounted for by omitting every second channel. A mathematical procedure was used to account for the crosstalk in next-neighbor channels. The speed and sensitivity of the PMT array system were found be superior to CCD cameras, allowing for measurement of more rapid changes in dose rate. This was further demonstrated by measuring the dose delivered by individual photon pulses of a linear accelerator beam. Conclusions: The PMT array system has advantages over CCD camera-based systems for the readout of scintillation light. It provided a more sensitive, more accurate, and faster response to meet the demands of future developments in treatment delivery.

  15. Mini Compton Camera Based on an Array of Virtual Frisch-Grid CdZnTe Detectors

    DOE PAGES

    Lee, Wonho; Bolotnikov, Aleksey; Lee, Taewoong; ...

    2016-02-15

    In this study, we constructed a mini Compton camera based on an array of CdZnTe detectors and assessed its spectral and imaging properties. The entire array consisted of 6×6 Frisch-grid CdZnTe detectors, each with a size of 6×6 ×15 mm3. Since it is easier and more practical to grow small CdZnTe crystals rather than large monolithic ones, constructing a mosaic array of parallelepiped crystals can be an effective way to build a more efficient, large-volume detector. With the fully operational CdZnTe array, we measured the energy spectra for 133Ba -, 137Cs -, 60Co-radiation sources; we also located these sources usingmore » a Compton imaging approach. Although the Compton camera was small enough to hand-carry, its intrinsic efficiency was several orders higher than those generated in previous researches using spatially separated arrays, because our camera measured the interactions inside the CZT detector array, wherein the detector elements were positioned very close to each other. Lastly, the performance of our camera was compared with that based on a pixelated detector.« less

  16. Mini Compton Camera Based on an Array of Virtual Frisch-Grid CdZnTe Detectors

    SciTech Connect

    Lee, Wonho; Bolotnikov, Aleksey; Lee, Taewoong; Camarda, Giuseppe; Cui, Yonggang; Gul, Rubi; Hossain, Anwar; Utpal, Roy; Yang, Ge; James, Ralph

    2016-02-15

    In this study, we constructed a mini Compton camera based on an array of CdZnTe detectors and assessed its spectral and imaging properties. The entire array consisted of 6×6 Frisch-grid CdZnTe detectors, each with a size of 6×6 ×15 mm3. Since it is easier and more practical to grow small CdZnTe crystals rather than large monolithic ones, constructing a mosaic array of parallelepiped crystals can be an effective way to build a more efficient, large-volume detector. With the fully operational CdZnTe array, we measured the energy spectra for 133Ba -, 137Cs -, 60Co-radiation sources; we also located these sources using a Compton imaging approach. Although the Compton camera was small enough to hand-carry, its intrinsic efficiency was several orders higher than those generated in previous researches using spatially separated arrays, because our camera measured the interactions inside the CZT detector array, wherein the detector elements were positioned very close to each other. Lastly, the performance of our camera was compared with that based on a pixelated detector.

  17. Two dimensional extensible array configuration for EMCCD-based solid state x-ray detectors

    NASA Astrophysics Data System (ADS)

    Sharma, P.; Swetadri Vasan, S. N.; Cartwright, A. N.; Titus, A. H.; Bednarek, D. R.; Rudin, S.

    2012-03-01

    We have designed and developed from the discrete component level a high resolution dynamic x-ray detector to be used for fluoroscopic and angiographic medical imaging. The heart of the detector is a 1024 ×1024 pixel electron multiplying charge coupled device (EMCCD) with a pixel size of 13 × 13 μm2 (Model CCD201-20, e2v Technologies, Inc.), bonded to a fiber optic plate (FOP), and optically coupled to a 350 μm thick micro-columnar CsI(TI) scintillator via a fiber optic taper (FOT). Our aim is to design an array of these detectors that could be extended to any arbitrary X × Y size in two dimensions to provide a larger field of view (FOV). A physical configuration for a 3×3 array is presented that includes two major sub-systems. First is an optical front end that includes (i) a phosphor to convert the x-ray photons into light photons, and (ii) a fused array of FOTs that focuses light photons from the phosphor onto an array of EMCCD's optically coupled using FOPs. Second is an electronic front end that includes (i) an FPGA board used for generating clocks and for data acquisition (ii) driver boards to drive and digitize the analog output from the EMCCDs, (iii) a power board, and (iv) headboards to hold the EMCCD's while they are connected to their respective driver board using flex cables. This configuration provides a larger FOV as well as region-of-interest (ROI) high-resolution imaging as required by modern neurovascular procedures.

  18. Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging

    PubMed Central

    Iwanczyk, Jan S.; Nygård, Einar; Meirav, Oded; Arenson, Jerry; Barber, William C.; Hartsough, Neal E.; Malakhov, Nail; Wessel, Jan C.

    2009-01-01

    The development of an innovative detector technology for photon-counting in X-ray imaging is reported. This new generation of detectors, based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detector arrays electrically connected to application specific integrated circuits (ASICs) for readout, will produce fast and highly efficient photon-counting and energy-dispersive X-ray imaging. There are a number of applications that can greatly benefit from these novel imagers including mammography, planar radiography, and computed tomography (CT). Systems based on this new detector technology can provide compositional analysis of tissue through spectroscopic X-ray imaging, significantly improve overall image quality, and may significantly reduce X-ray dose to the patient. A very high X-ray flux is utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm2/s in the unattenuated beam. High flux is required in order to collect sufficient photon statistics in the measurement of the transmitted flux (attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency requires the development of detector structures that can provide a response signal much faster than the transit time of carriers over the whole detector thickness. We have developed CdTe and CZT detector array structures which are 3 mm thick with 16×16 pixels and a 1 mm pixel pitch. These structures, in the two different implementations presented here, utilize either a small pixel effect or a drift phenomenon. An energy resolution of 4.75% at 122 keV has been obtained with a 30 ns peaking time using discrete electronics and a 57Co source. An output rate of 6×106 counts per second per individual pixel has been obtained with our ASIC readout electronics and a clinical CT X-ray tube. Additionally, the first clinical CT images, taken with several of our prototype photon-counting and energy

  19. Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging.

    PubMed

    Iwanczyk, Jan S; Nygård, Einar; Meirav, Oded; Arenson, Jerry; Barber, William C; Hartsough, Neal E; Malakhov, Nail; Wessel, Jan C

    2009-01-01

    The development of an innovative detector technology for photon-counting in X-ray imaging is reported. This new generation of detectors, based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detector arrays electrically connected to application specific integrated circuits (ASICs) for readout, will produce fast and highly efficient photon-counting and energy-dispersive X-ray imaging. There are a number of applications that can greatly benefit from these novel imagers including mammography, planar radiography, and computed tomography (CT). Systems based on this new detector technology can provide compositional analysis of tissue through spectroscopic X-ray imaging, significantly improve overall image quality, and may significantly reduce X-ray dose to the patient. A very high X-ray flux is utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm(2)/s in the unattenuated beam. High flux is required in order to collect sufficient photon statistics in the measurement of the transmitted flux (attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency requires the development of detector structures that can provide a response signal much faster than the transit time of carriers over the whole detector thickness. We have developed CdTe and CZT detector array structures which are 3 mm thick with 16×16 pixels and a 1 mm pixel pitch. These structures, in the two different implementations presented here, utilize either a small pixel effect or a drift phenomenon. An energy resolution of 4.75% at 122 keV has been obtained with a 30 ns peaking time using discrete electronics and a (57)Co source. An output rate of 6×10(6) counts per second per individual pixel has been obtained with our ASIC readout electronics and a clinical CT X-ray tube. Additionally, the first clinical CT images, taken with several of our prototype photon-counting and

  20. A four-pixel single-photon pulse-position array fabricated from WSi superconducting nanowire single-photon detectors

    SciTech Connect

    Verma, V. B. Horansky, R.; Lita, A. E.; Mirin, R. P.; Nam, S. W.; Marsili, F.; Stern, J. A.; Shaw, M. D.

    2014-02-03

    We demonstrate a scalable readout scheme for an infrared single-photon pulse-position camera consisting of WSi superconducting nanowire single-photon detectors. For an N × N array, only 2 × N wires are required to obtain the position of a detection event. As a proof-of-principle, we show results from a 2 × 2 array.

  1. The multi-element mercuric iodide detector array with computer controlled miniaturized electronics for EXAFS

    SciTech Connect

    Patt, B.E.; Iwanczyk, J.S.; Szczebiot, R.; Maculewicz, G.; Wang, M.; Wang, Y.J.; Hedman, B.; Hodgson, K.O.; Cox, A.D. |

    1995-08-01

    Construction of a 100-element HgI{sub 2} detector array, with miniaturized electronics, and software developed for synchrotron applications in the 5 keV to 35 keV region has been completed. Recently, extended x-ray absorption fine structure (EXAFS) data on dilute ({approximately} 1mM) metallo-protein samples were obtained with up to seventy-five elements of the system installed. The data quality obtained is excellent and shows that the detector is quite competitive as compared to commercially available systems. The system represents the largest detector array ever developed for high resolution, high count rate x-ray synchrotron applications. It also represents the first development and demonstration of high-density miniaturized spectroscopy electronics with this high level of performance. Lastly, the integration of the whole system into an automated computer-controlled environment represents a major advancement in the user interface for XAS measurements. These experiments clearly demonstrate that the HgI{sub 2} system, with the miniaturized electronics and associated computer control functions well. In addition it shows that the new system provides superior ease of use and functionality, and that data quality is as good as or better than with state-of-the-art cryogenically cooled Ge systems.

  2. The Indiana silicon sphere 4 π charged-particle detector array

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, K.; Bracken, D. S.; Morley, K. B.; Brzychczyk, J.; Foxford, E. Renshaw; Komisarcik, K.; Viola, V. E.; Yoder, N. R.; Dorsett, J.; Poehlman, J.; Madden, N.; Ottarson, J.

    1995-02-01

    A low threshold charged particle detector array for the study of fragmentation processes in light-ion-induced reactions has been constructed and successfully implemented at the IUCF and Saturne II accelerators. The array consists of 162-triple-element detector telescopes mounted in a spherical geometry and covering 74% of 4π in solid angle. Telescope elements are composed of (1) an axial-field gas ionization chamber operated with C3F8 gas; (2) a 0.5 mm thick passivated silicon detector, and (3) a 2.8 cm thick CsI(TI) scintillation crystal with photodiode readout. Discrete element identification is obtained for ejectiles up to Z ~ 16 over the dynamic range 0.7 <= E/A <= 95 MeV/nucleon. Isotopes are also distinguished for H, He, Li and Be ejectiles with 8 <~ E/A <~ 95 MeV. Custom-designed electronics are employed for bias supplies and linear signal processing. Data are acquired via a CAMAC/VME/Ethernet system.

  3. Population density estimated from locations of individuals on a passive detector array

    USGS Publications Warehouse

    Efford, Murray G.; Dawson, Deanna K.; Borchers, David L.

    2009-01-01

    The density of a closed population of animals occupying stable home ranges may be estimated from detections of individuals on an array of detectors, using newly developed methods for spatially explicit capture–recapture. Likelihood-based methods provide estimates for data from multi-catch traps or from devices that record presence without restricting animal movement ("proximity" detectors such as camera traps and hair snags). As originally proposed, these methods require multiple sampling intervals. We show that equally precise and unbiased estimates may be obtained from a single sampling interval, using only the spatial pattern of detections. This considerably extends the range of possible applications, and we illustrate the potential by estimating density from simulated detections of bird vocalizations on a microphone array. Acoustic detection can be defined as occurring when received signal strength exceeds a threshold. We suggest detection models for binary acoustic data, and for continuous data comprising measurements of all signals above the threshold. While binary data are often sufficient for density estimation, modeling signal strength improves precision when the microphone array is small.

  4. THE COSMIC-RAY ENERGY SPECTRUM OBSERVED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT

    SciTech Connect

    Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W.; Aida, R.; Azuma, R.; Fukuda, T.; Cheon, B. G.; Cho, E. J.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukushima, M.; and others

    2013-05-01

    The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays (UHECRs) with primary energies above 1.6 Multiplication-Sign 10{sup 18} eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 Multiplication-Sign 10{sup 18} eV and a steepening at 5.4 Multiplication-Sign 10{sup 19} eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of UHECR surface detector data, that involves generating a complete simulation of UHECRs striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the ''thinning'' approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned.

  5. β-Decay Studies of r-Process Nuclei Using the Advanced Implantation Detector Array (AIDA)

    NASA Astrophysics Data System (ADS)

    Griffin, C. J.; Davinson, T.; Estrade, A.; Braga, D.; Burrows, I.; Coleman-Smith, P. J.; Grahn, T.; Grant, A.; Harkness-Brennan, L. J.; Kiss, G.; Kogimtzis, M.; Lazarus, I. H.; Letts, S. C.; Liu, Z.; Lorusso, G.; Matsui, K.; Nishimura, S.; Page, R. D.; Prydderch, M.; Phong, V. H.; Pucknell, V. F. E.; Rinta-Antila, S.; Roberts, O. J.; Seddon, D. A.; Simpson, J.; Thomas, S. L.; Woods, P. J.

    Thought to produce around half of all isotopes heavier than iron, the r-process is a key mechanism for nucleosynthesis. However, a complete description of the r-process is still lacking and many unknowns remain. Experimental determination of β-decay half-lives and β-delayed neutron emission probabilities along the r-process path would help to facilitate a greater understanding of this process. The Advanced Implantation Detector Array (AIDA) represents the latest generation of silicon implantation detectors for β-decay studies with fast radioactive ion beams. Preliminary results from commissioning experiments demonstrate successful operation of AIDA and analysis of the data obtained during the first official AIDA experiments is now under-way.

  6. Fabrication and Characterization of Linear Terahertz Detector Arrays Based on Lithium Tantalate Crystal

    NASA Astrophysics Data System (ADS)

    Li, Weizhi; Wang, Jun; Gou, Jun; Huang, Zehua; Jiang, Yadong

    2015-01-01

    Two samples of 30-pixel linear terahertz detector arrays (TDAs) were fabricated based on lithium tantalate (LT) crystals. Pixel readout circuit (ROC) was designed to extract the weak current signal of TDAs. A test platform was established for performance evaluation of TDA+ROC components. By using a 2.52THz laser as radiation source, the test results reveal that average voltage responsivities of the components were larger than 7000V/W and non-uniformity no more than 2.1%. Average noise equivalent power ( NEP) of one sample was measured to be 1.5×10-9 W/Hz1/2, which is low enough and desirable for high performance THz detector.

  7. A new linear array detector for high resolution and low dose digital radiography

    NASA Astrophysics Data System (ADS)

    Bettuzzi, Matteo; Cornacchia, Samantha; Rossi, Massimo; Paltrinieri, Enrica; Morigi, Maria Pia; Brancaccio, Rosa; Romani, Davide; Casali, Franco

    2004-01-01

    At the Department of Physics of the University of Bologna a new intensified linear array detector is under development. The core of the system is a digital intensified CCD camera, the electron bombarded charge coupled device (EBCCD). The main innovation is a coherent rectangular-to-linear fiber optics adapter coupling the 1 in. diameter photocathode of the camera with a linear 129 mm × 1.45 mm strip of Gd 2O 2S:Tb. In this way a high spatial resolution over an extended length is obtained. The detector works as an X-ray scanner by means of a high-precision translation mechanical device to inspect a 13 cm × 18 cm area. A complete characterisation of the system has been made in terms of linearity, dynamic range, modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE). At last, radiographic tests on a set of samples have been made and will be presented.

  8. Mosaic wedge-and-strip arrays for large format microchannel plate detectors

    NASA Technical Reports Server (NTRS)

    Martin, Christopher; Rasmussen, Andrew

    1989-01-01

    The authors present a novel method for joining wedge-and-strip patterns on single anodes in a mosaic array. With only a modest increase in complexity over three-conductor anodes currently in use, the ultimate detector position resolution can be significantly improved, and large-format microchannel plate detectors with pore-size-limited resolution are made possible. The problem of the transition from one anode to the next has been solved with a novel linear encoding scheme, which exhibits essentially distortionless behavior at boundaries parallel to the conducting elements and only slight distortion at the orthogonal boundaries. The ultimate resolution for two anode designs, one designed for large-format imaging and the other for high-resolution spectroscopy, is also predicted.

  9. A compact pulse shape discriminator module for large neutron detector arrays

    NASA Astrophysics Data System (ADS)

    Venkataramanan, S.; Gupta, Arti; Golda, K. S.; Singh, Hardev; Kumar, Rakesh; Singh, R. P.; Bhowmik, R. K.

    2008-11-01

    A cost-effective high-performance pulse shape discriminator module has been developed to process signals from organic liquid scintillator-based neutron detectors. This module is especially designed for the large neutron detector array used for studies of nuclear reaction dynamics at the Inter University Accelerator Center (IUAC). It incorporates all the necessary pulse processing circuits required for neutron spectroscopy in a novel fashion by adopting the zero crossover technique for neutron-gamma (n- γ) pulse shape discrimination. The detailed layout of the circuit and different features of the module are described in the present paper. The quality of n- γ separation obtained with this electronics is much better than that of commercial modules especially in the low-energy region. The results obtained with our module are compared with similar setups available in other laboratories.

  10. A Failure Mode in Dense Infrared Detector Arrays Resulting in Increased Dark Current

    NASA Astrophysics Data System (ADS)

    Pinkie, Benjamin; Bellotti, Enrico

    2016-09-01

    In this paper, we investigate a failure mode that arises in dense infrared focal plane detector arrays as a consequence of the interactions of neighboring pixels through the minority carrier profiles in the common absorber layer. We consider the situation in which one pixel in a hexagonal array becomes de-biased relative to its neighbors and show that the dark current in the six neighboring pixels increases exponentially as a function of the difference between the nominal and anomalous biases. Moreover, we show that the current increase in the six nearest-neighbor pixels is in total larger than that by which the current in the affected pixel decreases, causing a net increase in the dark current. The physical origins of this effect are explained as being due to increased lateral diffusion currents that arise as a consequence of breaking the symmetry of the minority carrier profiles. We then perform a parametric study to quantify the magnitude of this effect for a number of detector geometric parameters, operating temperatures, and spectral bands. Particularly, numerical simulations are carried out for short-, mid-, and long-wavelength HgCdTe infrared detectors operating between 77 K and 210 K. We show that this effect is most prevalent in architectures for which the lateral diffusion current is the largest component of the total dark current—high operating temperature devices with narrow epitaxial absorber thicknesses and pitches small compared to the diffusion length of minority carriers. These results could prove significant particularly for short- and mid-wave infrared detectors, which are typically designed to fit these conditions.

  11. Evaluation of a far infrared Ge:Ga multiplexed detector array

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam; Mccreight, Craig

    1990-01-01

    The performance of a multielement Ge:Ga linear array under low-background conditions is investigated. On-focal plane switching is accomplished by MOSFET switches and the integrated charge is made available through MOSFET source followers. The tests were conducted at 106 microns and the radiation on the detectors was confined to a spectral window 1.25 microns wide using a stack of cold filters. At 4.2 K, the responsivity was measured to be nominally 584 A/W, and the NEP was 1.0 x 10 exp -16 W/sq rt Hz. A detailed description of the test setup and the procedure is presented.

  12. Radioactive Background Measurements in the Neutral Current Detector Array at SNO

    NASA Astrophysics Data System (ADS)

    Cox, G. A.; Doe, P. J.; Formaggio, J. A.; McGee, S.; Stonehill, L. C.; Robertson, R. G. H.; Wall, B. L.; Wilkerson, J. F. W.; Hallin, A. L.; Poon, A. W. P.; Wouters, J. M.

    2003-10-01

    The third phase of data taking at the Sudbury Neutrino Observatory (SNO) is currently scheduled to begin in the autumn of 2003 with the installation of the Neutral Current Detectors (NCD). The NCDs, an array of ^3He proportional counters constructed from ultra-pure nickel, will measure the flux of ^8B solar neutrinos at SNO. The major sources of internal backgrounds in the NCD counters arise from U and Th chain decays. Analysis techniques have been developed to determine the level of these contaminations. These techniques and the impact of the U and Th levels on the neutral current flux measurement will be discussed.

  13. Short range laser obstacle detector. [for surface vehicles using laser diode array

    NASA Technical Reports Server (NTRS)

    Kuriger, W. L. (Inventor)

    1973-01-01

    A short range obstacle detector for surface vehicles is described which utilizes an array of laser diodes. The diodes operate one at a time, with one diode for each adjacent azimuth sector. A vibrating mirror a short distance above the surface provides continuous scanning in elevation for all azimuth sectors. A diode laser is synchronized with the vibrating mirror to enable one diode laser to be fired, by pulses from a clock pulse source, a number of times during each elevation scan cycle. The time for a given pulse of light to be reflected from an obstacle and received is detected as a measure of range to the obstacle.

  14. Observation of high energy atmospheric neutrinos with antarctic muon and neutrino detector array

    SciTech Connect

    Ahrens, J.; Andres, E.; Bai, X.; Barouch, G.; Barwick, S.W.; Bay, R.C.; Becka, T.; Becker, K.-H.; Bertrand, D.; Binon, F.; Biron, A.; Booth, J.; Botner, O.; Bouchta, A.; Bouhali, O.; Boyce, M.M.; Carius, S.; Chen, A.; Chirkin, D.; Conrad, J.; Cooley, J.; Costa, C.G.S.; Cowen, D.F.; Dalberg, E.; De Clercq, C.; DeYoung, T.; Desiati, P.; Dewulf, J.-P.; Doksus, P.; Edsjo, J.; Ekstrom, P.; Feser, T.; Frere, J.-M.; Gaisser, T.K.; Gaug, M.; Goldschmidt, A.; Hallgren, A.; Halzen, F.; Hanson, K.; Hardtke, R.; Hauschildt, T.; Hellwig, M.; Heukenkamp, H.; Hill, G.C.; Hulth, P.O.; Hundertmark, S.; Jacobsen, J.; Karle, A.; Kim, J.; Koci, B.; Kopke, L.; Kowalski, M.; Lamoureux, J.I.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Loaiza, P.; Lowder, D.M.; Madsen, J.; Marciniewski, P.; Matis, H.S.; McParland, C.P.; Miller, T.C.; Minaeva, Y.; Miocinovic, P.; Mock, P.C.; Morse, R.; Neunhoffer, T.; Niessen, P.; Nygren, D.R.; Ogelman, H.; Olbrechts, Ph.; Perez de los Heros, C.; Pohl, A.C.; Porrata, R.; Price, P.B.; Przybylski, G.T.; Rawlins, K.; Reed, C.; Rhode, W.; Ribordy, M.; Richter, S.; Rodriguez Martino, J.; Romenesko, P.; Ross, D.; Sander, H.-G.; Schmidt, T.; Schneider, D.; Schwarz, R.; Silvestri, A.; Solarz, M.; Spiczak, G.M.; Spiering, C.; Starinsky, N.; Steele, D.; Steffen, P.; Stokstad, R.G.; Streicher, O.; Sudhoff, P.; Sulanke, K.-H.; Taboada, I.; Thollander, L.; Thon, T.; Tilav, S.; Vander Donckt, M.; Walck, C.; Weinheimer, C.; Wiebusch, C.H.; Wiedeman, C.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Wu, W.; Yodh, G.; Young, S.

    2002-05-07

    The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10{sup 6} times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05 x 10{sup 9} cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulations indicate that 90 percent of these events lie in the energy range 66 GeV to 3.4 TeV. The observation of atmospheric neutrinos consistent with expectations establishes AMANDA-B10 as a working neutrino telescope.

  15. DENSITY: software for analysing capture-recapture data from passive detector arrays

    USGS Publications Warehouse

    Efford, M.G.; Dawson, D.K.; Robbins, C.S.

    2004-01-01

    A general computer-intensive method is described for fitting spatial detection functions to capture-recapture data from arrays of passive detectors such as live traps and mist nets. The method is used to estimate the population density of 10 species of breeding birds sampled by mist-netting in deciduous forest at Patuxent Research Refuge, Laurel, Maryland, U.S.A., from 1961 to 1972. Total density (9.9 ? 0.6 ha-1 mean ? SE) appeared to decline over time (slope -0.41 ? 0.15 ha-1y-1). The mean precision of annual estimates for all 10 species pooled was acceptable (CV(D) = 14%). Spatial analysis of closed-population capture-recapture data highlighted deficiencies in non-spatial methodologies. For example, effective trapping area cannot be assumed constant when detection probability is variable. Simulation may be used to evaluate alternative designs for mist net arrays where density estimation is a study goal.

  16. Performance of A Compact Multi-crystal High-purity Germanium Detector Array for Measuring Coincident Gamma-ray Emissions

    SciTech Connect

    Howard, Chris; Daigle, Stephen; Buckner, Matt; Erikson, Luke E.; Runkle, Robert C.; Stave, Sean C.; Champagne, Art; Cooper, Andrew; Downen, Lori; Glasgow, Brian D.; Kelly, Keegan; Sallaska, Anne

    2015-02-18

    The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the 14N(p,γ)15O* reaction for several transition energies at an effective center of mass energy of 163 keV. Owing to the segmented nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within the uncertainties with the past measurements. Details of the analysis and detector performance will be presented.

  17. Graphical User Interface for a Dual-Module EMCCD X-ray Detector Array.

    PubMed

    Wang, Weiyuan; Ionita, Ciprian; Kuhls-Gilcrist, Andrew; Huang, Ying; Qu, Bin; Gupta, Sandesh K; Bednarek, Daniel R; Rudin, Stephen

    2011-03-16

    A new Graphical User Interface (GUI) was developed using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) for a high-resolution, high-sensitivity Solid State X-ray Image Intensifier (SSXII), which is a new x-ray detector for radiographic and fluoroscopic imaging, consisting of an array of Electron-Multiplying CCDs (EMCCDs) each having a variable on-chip electron-multiplication gain of up to 2000× to reduce the effect of readout noise. To enlarge the field-of-view (FOV), each EMCCD sensor is coupled to an x-ray phosphor through a fiberoptic taper. Two EMCCD camera modules are used in our prototype to form a computer-controlled array; however, larger arrays are under development. The new GUI provides patient registration, EMCCD module control, image acquisition, and patient image review. Images from the array are stitched into a 2k×1k pixel image that can be acquired and saved at a rate of 17 Hz (faster with pixel binning). When reviewing the patient's data, the operator can select images from the patient's directory tree listed by the GUI and cycle through the images using a slider bar. Commonly used camera parameters including exposure time, trigger mode, and individual EMCCD gain can be easily adjusted using the GUI. The GUI is designed to accommodate expansion of the EMCCD array to even larger FOVs with more modules. The high-resolution, high-sensitivity EMCCD modular-array SSXII imager with the new user-friendly GUI should enable angiographers and interventionalists to visualize smaller vessels and endovascular devices, helping them to make more accurate diagnoses and to perform more precise image-guided interventions.

  18. Graphical user interface for a dual-module EMCCD x-ray detector array

    NASA Astrophysics Data System (ADS)

    Wang, Weiyuan; Ionita, Ciprian; Kuhls-Gilcrist, Andrew; Huang, Ying; Qu, Bin; Gupta, Sandesh K.; Bednarek, Daniel R.; Rudin, Stephen

    2011-03-01

    A new Graphical User Interface (GUI) was developed using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) for a high-resolution, high-sensitivity Solid State X-ray Image Intensifier (SSXII), which is a new x-ray detector for radiographic and fluoroscopic imaging, consisting of an array of Electron-Multiplying CCDs (EMCCDs) each having a variable on-chip electron-multiplication gain of up to 2000x to reduce the effect of readout noise. To enlarge the field-of-view (FOV), each EMCCD sensor is coupled to an x-ray phosphor through a fiberoptic taper. Two EMCCD camera modules are used in our prototype to form a computer-controlled array; however, larger arrays are under development. The new GUI provides patient registration, EMCCD module control, image acquisition, and patient image review. Images from the array are stitched into a 2kx1k pixel image that can be acquired and saved at a rate of 17 Hz (faster with pixel binning). When reviewing the patient's data, the operator can select images from the patient's directory tree listed by the GUI and cycle through the images using a slider bar. Commonly used camera parameters including exposure time, trigger mode, and individual EMCCD gain can be easily adjusted using the GUI. The GUI is designed to accommodate expansion of the EMCCD array to even larger FOVs with more modules. The high-resolution, high-sensitivity EMCCD modular-array SSXII imager with the new user-friendly GUI should enable angiographers and interventionalists to visualize smaller vessels and endovascular devices, helping them to make more accurate diagnoses and to perform more precise image-guided interventions.

  19. WE-AB-BRB-09: Real Time In Vivo Scintillating Fiber Array Detector for Medical LINACS

    SciTech Connect

    Knewtson, T; Pokhrel, S; Hernandez-Morales, D; Loyalka, S; Rangaraj, D; Izaguirre, E; Price, S

    2015-06-15

    Purpose: An in vivo transmission scintillation fiber detector was developed to monitor patient treatment in real time for the enhancement of patient safety and treatment accuracy. The detector system is capable of monitoring each pulse from a medical LINAC during treatment to determine the dose delivered as treatment progresses. Methods: The detector system consists of 60 parallel scintillating fibers coupled to fast data processing optoelectronics that can monitor the beam fluence in real time. Each 2.5mm{sup 2} square fiber is aligned with an MLC leaf pair and is long enough to capture a 40cm field. The fibers are embedded within a water equivalent polymer substrate that is secured in the LINAC accessory tray. The fibers are coupled to high speed photosensors and front end amplifiers that filter noise and pass each pulse to a high speed analog-to-digital converter. The system components are capable of detecting pulse repetition times shorter than what is delivered by a medical LINAC to ensure true real time data acquisition. Results: The system was able to capture and record the signal from each linac pulse and display the information in real time with no pulse pile up. It was found that the fiber array attenuates 2.65% of the beam which can easily be compensated for in treatment planning. The fibers responded linearly with dose, are independent of clinical beam energies, and are independent of dose rate. Calibration of the system was performed as a function of beam energy, beam size, dose rate, and monitor units to optimize beam fluence error detection. Conclusion: The detector system presented provides true real time in vivo beam monitoring to enhance patient safety and treatment delivery accuracy. Furthermore, the detector can be used for current patient specific QA.

  20. Development of novel on-chip, customer-design spiral biasing adaptor on for Si drift detectors and detector arrays for X-ray and nuclear physics experiments

    NASA Astrophysics Data System (ADS)

    Li, Zheng; Chen, Wei

    2014-11-01

    A novel on-chip, customer-design spiral biasing adaptor (SBA) has been developed. A single SBA is used for biasing a Si drift detector (SDD) and SDD array. The use of an SBA reduces the biasing current. This paper shows the calculation of the geometry of an SBA and an SDD to get the best drift field in the SDD and SDD array. Prototype SBAs have been fabricated to verify the concept. Electrical measurements on these SBAs are in agreement with the expectations. The new SDD array with an SBA can be used for X-ray detection and in nuclear physics experiments.

  1. Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging.

    PubMed

    Hack, Erwin; Valzania, Lorenzo; Gäumann, Gregory; Shalaby, Mostafa; Hauri, Christoph P; Zolliker, Peter

    2016-02-06

    In terahertz (THz) materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8-14 μm wavelength range, but are based on different absorber materials (i) vanadium oxide; (ii) amorphous silicon; (iii) a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv) a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

  2. Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging

    PubMed Central

    Hack, Erwin; Valzania, Lorenzo; Gäumann, Gregory; Shalaby, Mostafa; Hauri, Christoph P.; Zolliker, Peter

    2016-01-01

    In terahertz (THz) materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8–14 μm wavelength range, but are based on different absorber materials (i) vanadium oxide; (ii) amorphous silicon; (iii) a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv) a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed. PMID:26861341

  3. Performance assessment of a 2D array of plastic scintillation detectors for IMRT quality assurance

    NASA Astrophysics Data System (ADS)

    Guillot, Mathieu; Gingras, Luc; Archambault, Louis; Beddar, Sam; Beaulieu, Luc

    2013-07-01

    The purposes of this work are to assess the performance of a 2D plastic scintillation detectors array prototype for quality assurance in intensity-modulated radiation therapy (IMRT) and to determine its sensitivity and specificity to positioning errors of one multileaf collimator (MLC) leaf and one MLC leaf bank by applying the principles of signal detection theory. Ten treatment plans (step-and-shoot delivery) and one volumetric modulated arc therapy plan were measured and compared to calculations from two treatment-planning systems (TPSs) and to radiochromic films. The averages gamma passing rates per beam found for the step-and-shoot plans were 95.8% for the criteria (3%, 2 mm), 97.8% for the criteria (4%, 2 mm), and 98.1% for the criteria (3%, 3 mm) when measurements were compared to TPS calculations. The receiver operating characteristic curves for the one leaf errors and one leaf bank errors were determined from simulations (theoretical upper limits) and measurements. This work concludes that arrays of plastic scintillation detectors could be used for IMRT quality assurance in clinics. The use of signal detection theory could improve the quality of dosimetric verifications in radiation therapy by providing optimal discrimination criteria for the detection of different classes of errors.

  4. CMOS detector arrays in a virtual 10-kilopixel camera for coherent terahertz real-time imaging.

    PubMed

    Boppel, Sebastian; Lisauskas, Alvydas; Max, Alexander; Krozer, Viktor; Roskos, Hartmut G

    2012-02-15

    We demonstrate the principle applicability of antenna-coupled complementary metal oxide semiconductor (CMOS) field-effect transistor arrays as cameras for real-time coherent imaging at 591.4 GHz. By scanning a few detectors across the image plane, we synthesize a focal-plane array of 100×100 pixels with an active area of 20×20 mm2, which is applied to imaging in transmission and reflection geometries. Individual detector pixels exhibit a voltage conversion loss of 24 dB and a noise figure of 41 dB for 16 μW of the local oscillator (LO) drive. For object illumination, we use a radio-frequency (RF) source with 432 μW at 590 GHz. Coherent detection is realized by quasioptical superposition of the image and the LO beam with 247 μW. At an effective frame rate of 17 Hz, we achieve a maximum dynamic range of 30 dB in the center of the image and more than 20 dB within a disk of 18 mm diameter. The system has been used for surface reconstruction resolving a height difference in the μm range.

  5. Performance analysis of MIMO FSO systems with radial array beams and finite sized detectors

    NASA Astrophysics Data System (ADS)

    Gökçe, Muhsin C.; Kamacıoǧlu, Canan; Uysal, Murat; Baykal, Yahya

    2014-10-01

    Multiple-input multiple-output (MIMO) systems are employed in free space optical (FSO) links to mitigate the degrading effects of atmospheric turbulence. In this paper, we consider a MIMO FSO system with practical transmitter and receiver configurations that consists of a radial laser array with Gaussian beams and finite sized detectors. We formulate the average received intensity and the power scinitillation as a function of the receiver coordinates in the presence of weak atmospheric turbulence by using the extended Huygens-Fresnel principle. Then, integrations over the finite sized multiple detectors are performed and the effect of the receiver aperture averaging is quantified. We further derive an outage probability expression of this MIMO system in the presence of turbulence-induced fading channels. Using the derived expressions, we demonstrate the effect of several practical system parameters such as the ring radius, the number of array beamlets, the source size, the link length, structure constant and the receiver aperture radius on the system performance.

  6. Small-angle scatter tomography with a photon-counting detector array

    NASA Astrophysics Data System (ADS)

    Pang, Shuo; Zhu, Zheyuan; Wang, Ge; Cong, Wenxiang

    2016-05-01

    Small-angle x-ray scatter imaging has a high intrinsic contrast in cancer research and other applications, and provides information on molecular composition and micro-structure of the tissue. In general, the implementations of small-angle coherent scatter imaging can be divided into two main categories: direct tomography and angular dispersive computerized tomography. Based on the recent development of energy-discriminative photon-counting detector array, here we propose a computerized tomography setup based on energy-dispersive measurement with a photon-counting detector array. To show merits of the energy-dispersive approach, we have performed numerical tests with a phantom containing various tissue types, in comparison with the existing imaging approaches. The results show that with an energy resolution of ~6 keV, the energy dispersive tomography system with a broadband tabletop x-ray would outperform the angular dispersive system, which makes the x-ray small-angle scatter tomography promising for high-specificity tissue imaging.

  7. Spectrum measurement with the Telescope Array Low Energy Extension (TALE) fluorescence detector

    NASA Astrophysics Data System (ADS)

    Zundel, Zachary James

    The Telescope Array (TA) experiment is the largest Ultra High Energy cosmic ray observatory in the northern hemisphere and is designed to be sensitive to cosmic ray air showers above 1018eV. Despite the substantial measurements made by TA and AUGER (the largest cosmic ray observatory in the southern hemisphere), there remains uncertainty about whether the highest energy cosmic rays are galactic or extragalactic in origin. Locating features in the cosmic ray energy spectrum below 1018eV that indicate a transition from galactic to extragalactic sources would clarify the interpretation of measurements made at the highest energies. The Telescope Array Low Energy Extension (TALE) is designed to extend the energy threshold of the TA observatory down to 1016.5eV in order to make such measurements. This dissertation details the construction, calibration, and operation of the TALE flu- orescence detector. A measurement of the flux of cosmic rays in the energy range of 1016.5 -- 1018.5eV is made using the monocular data set taken between September 2013 and January 2014. The TALE fluorescence detector observes evidence for a softening of the cosmic spectrum at 1017.25+/-0.5eV. The evidence of a change in the spectrum motivates continued study of 1016.5 -- 1018.5eV cosmic rays.

  8. Preliminary results from a novel CdZnTe linear pad detector array x-ray imaging system

    SciTech Connect

    Peng, J.; Tuemer, T.O.; Petrini, B.M.; Kravis, S.D.; Yin, S.; Parnham, K.B.; Glick, B.; Willson, P.D.

    1996-12-31

    The excellent energy-resolution and short charge collection time, especially the possibility of room temperature operation, make CdZnTe semiconductor detectors an excellent candidate for x-ray imaging and spectroscopic application in nuclear physics. Because of these characteristics, CdZnTe pad detectors with a novel geometry and approximately 1 mm{sup 2} pad area have been developed. These pad type linear arrays are new and important for many scanning type applications using a wide energy range from about 10 to 300 keV energies. A prototype x-ray imaging system has been developed consisting of a state-of-the-art pad type linear array of CdZnTe detectors manufactured by eV Products and low noise readout electronics developed by NOVA R and D, Inc. A series of measurements on the temperature dependence of the performance of CdZnTe linear pad detector arrays has been performed at NOVA R and D, Inc. The changes in dark (leakage) current against temperature have been studied. High resolution x-ray spectra has been obtained using {sup 57}Co source at different temperatures. A low noise front-end electronics ASIC chip for reading out the detector array was developed that can achieve fast data acquisition with dual energy imaging capability. Several prototype CdZnTe pad detector arrays are placed next to each other to form an approximately 30 cm long linear array. This array is used to make preliminary dual energy scanned images of complex objects using a 90 kV x-ray generator. Some of the images will be presented. The results show that the system is excellent for applications in industrial and medical imaging.

  9. A 2-D Array of Superconducting Magnesium Diboride (MgB2) Far-IR Thermal Detectors for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Lakew, Brook

    2009-01-01

    A 2-D array of superconducting Magnesium Diboride(MgB2) far IR thermal detectors has been fabricated. Such an array is intended to be at the focal plane of future generation thermal imaging far-IR instruments that will investigate the outer planets and their icy moons. Fabrication and processing of the pixels of the array as well as noise characterization of architectured MgB2 thin films will be presented. Challenges and solutions for improving the performance of the array will be discussed.

  10. CSI: Immigrant Children--Clues for Teacher Education

    ERIC Educational Resources Information Center

    Larke, Patricia J.

    2012-01-01

    The metaphor of the popular television shows "CSI: New York," "CSI: Miami," and "CSI: Las Vegas" (CSI stands for "crime scene investigation") is applicable to investigating issues of immigrant children in teacher preparation programs (TPP). One of the fundamental principles of CSI is to solve the crime by…

  11. Proton irradiation results for long-wave HgCdTe infrared detector arrays for Near-Earth Object Camera

    NASA Astrophysics Data System (ADS)

    Dorn, Meghan L.; Pipher, Judith L.; McMurtry, Craig; Hartman, Spencer; Mainzer, Amy; McKelvey, Mark; McMurray, Robert; Chevara, David; Rosser, Joshua

    2016-07-01

    HgCdTe detector arrays with a cutoff wavelength of ˜10 μm intended for the Near-Earth Object Camera (NEOCam) space mission were subjected to proton-beam irradiation at the University of California Davis Crocker Nuclear Laboratory. Three arrays were tested-one with 800-μm substrate intact, one with 30-μm substrate, and one completely substrate-removed. The CdZnTe substrate, on which the HgCdTe detector is grown, has been shown to produce luminescence in shorter wave HgCdTe arrays that causes an elevated signal in nonhit pixels when subjected to proton irradiation. This testing was conducted to ascertain whether or not full substrate removal is necessary. At the dark level of the dewar, we detect no luminescence in nonhit pixels during proton testing for both the substrate-removed detector array and the array with 30-μm substrate. The detector array with full 800-μm substrate exhibited substantial photocurrent for a flux of 103 protons/cm2 s at a beam energy of 18.1 MeV (˜750 e-/s) and 34.4 MeV (˜65 e-/s). For the integrated space-like ambient proton flux level measured by the Spitzer Space Telescope, the luminescence would be well below the NEOCam dark current requirement of <200 e-/s, but the pattern of luminescence could be problematic, possibly complicating calibration.

  12. Dosimetric performance and array assessment of plastic scintillation detectors for stereotactic radiosurgery quality assurance

    SciTech Connect

    Gagnon, Jean-Christophe; Theriault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc

    2012-01-15

    Purpose: To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. Methods: The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S{sub c,p}) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Results: Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 x 10 cm{sup 2} field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S{sub c,p} within 1.4% and 0.7% for 5 and 35 mm diameter cone

  13. Analyzing the performance of ArcCHECK diode array detector for VMAT plan

    PubMed Central

    Thiyagarajan, Rajesh; Nambiraj, Arunai; Sinha, Sujit Nath; Yadav, Girigesh; Kumar, Ashok; Subramani, Vikraman; Kothandaraman

    2016-01-01

    Aim The aim of this study is to evaluate performance of ArcCHECK diode array detector for the volumetric modulated arc therapy (VMAT) patient specific quality assurance (QA). VMAT patient specific QA results were correlated with ion chamber measurement. Dose response of the ArcCHECK detector was studied. Background VMAT delivery technique improves the dose distribution. It is complex in nature and requires proper QA before its clinical implementation. ArcCHECK is a novel three dimensional dosimetry system. Materials and methods Twelve retrospective VMAT plans were calculated on ArcCHECK phantom. Point dose and dose map were measured simultaneously with ion chamber (IC-15) and ArcCHECK diode array detector, respectively. These measurements were compared with their respective TPS calculated values. Results The ion chamber measurements are in good agreement with TPS calculated doses. Mean difference between them is 0.50% with standard deviation of 0.51%. Concordance correlation coefficient (CCC) obtained for ion chamber measurements is 0.9996. These results demonstrate a strong correlation between the absolute dose predicted by our TPS and the measured dose. The CCC between ArcCHECK doses and TPS predictions on the CAX was found to be 0.9978. In gamma analysis of dose map, the mean passing rate was 98.53% for 3% dose difference and 3 mm distance to agreement. Conclusions The VMAT patient specific QA with an ion chamber and ArcCHECK phantom are consistent with the TPS calculated dose. Statistically good agreement was observed between ArcCHECK measured and TPS calculated. Hence, it can be used for routine VMAT QA. PMID:26900358

  14. Diagnostic and quality-assurance tools for low-contrast images obtained from array detectors

    NASA Technical Reports Server (NTRS)

    Hatfield, D. B.; Sandel, Bill R.

    1993-01-01

    We investigate methods of estimating a background image frame for subtraction from a data frame for use when a more suitable measured background frame is not available. We define background as any signal component that is not attributable to the phenomenon currently under investigation. We describe a technique that is based on pixel-by-pixel least-squares regression of images for computing a background frame from available data. We argue that the same technique can be a useful quality-assurance tool for evaluating instrument performance. For example, it can help to separate image structure resulting from the reading process from structure resulting from the characteristics of the detector itself. We demonstrate that background estimation can be nontrivial by comparing the results of different background estimation procedures by using data obtained from a CCD array detector. We investigate the temperature-dependent contributions of the detector and readout electronics to the total signal as a demonstration of the diagnostic capabilities of least-squares image regression.

  15. A slot-scanned photodiode-array/CCD hybrid detector for digital mammography.

    PubMed

    Mainprize, James G; Ford, Nancy L; Yin, Shi; Tümer, Türmay; Yaffe, Martin J

    2002-02-01

    We have developed a novel direct conversion detector for use in a slot-scanning digital mammography system. The slot-scan concept allows for dose efficient scatter rejection and the ability to use small detectors to produce a large-area image. The detector is a hybrid design with a 1.0 mm thick silicon PIN photodiode array (the x-ray absorber) indium-bump bonded to a CCD readout that is operated in time-delay integration (TDI) mode. Because the charge capacity requirement for good image quality exceeds the capabilities of standard CCDs, a novel CCD was developed. This CCD consists of 24 independent sections, each acting as a miniature CCD with eight rows for TDI. The signal from each section is combined off-chip to produce a full signal image. The MTF and DQE for the device was measured at several exposures and compared to a linear systems model of signal and noise propagation. Because of the scanning nature of TDI imaging, both the MTF(f) and DQE(f) are reduced along the direction of the scanning motion. For a 26 kVp spectrum, the DQE(0) was measured to be 0.75+/-0.02 for an exposure of 1.29 x 10(-5) C/kg (50 mR).

  16. Photoconductive terahertz near-field detector with a hybrid nanoantenna array cavity

    DOE PAGES

    Mitrofanov, Oleg; Brener, Igal; Luk, Ting S.; ...

    2015-11-19

    Nanoscale structuring of optical materials leads to modification of their properties and can be used for improving efficiencies of photonic devices and for enabling new functionalities. In ultrafast optoelectronic switches for generation and detection of terahertz (THz) radiation, incorporation of nanostructures allows us to overcome inherent limitations of photoconductive materials. We propose and demonstrate a nanostructured photoconductive THz detector for sampling highly localized THz fields, down to the level of λ/150. The nanostructure that consists of an array of optical nanoantennas and a distributed Bragg reflector forms a hybrid cavity, which traps optical gate pulses within the photoconductive layer. Themore » effect of photon trapping is observed as enhanced absorption at a designed wavelength. This optically thin photoconductive THz detector allows us to detect highly confined evanescent THz fields coupled through a deeply subwavelength aperture as small as 2 μm (λ/150 at 1 THz). As a result, by monolithically integrating the THz detector with apertures ranging from 2 to 5 μm we realize higher spatial resolution and higher sensitivity in aperture-type THz near-field microscopy and THz time-domain spectroscopy.« less

  17. A Deuterated Neutron Detector Array For Nuclear (Astro)Physics Studies

    NASA Astrophysics Data System (ADS)

    Almaraz-Calderon, Sergio; Asher, B. W.; Barber, P.; Hanselman, K.; Perello, J. F.

    2016-09-01

    The properties of neutron-rich nuclei are at the forefront of research in nuclear structure, nuclear reactions and nuclear astrophysics. The advent of intense rare isotope beams (RIBs) has opened a new door for studies of systems with very short half-lives and possible fascinating properties. Neutron spectroscopic techniques become increasingly relevant when these neutron rich nuclei are used in a variety of experiments. At Florida State University, we are developing a neutron detector array that will allow us to perform high-resolution neutron spectroscopic studies with stable and radioactive beams. The neutron detection system consists of 16 deuterated organic liquid scintillation detectors with fast response and pulse-shape discrimination capabilities. In addition to these properties, there is the potential to use the structure in the pulse-height spectra to extract the energy of the neutrons and thus produce directly excitation spectra. This type of detector uses deuterated benzene (C6D6) as the liquid scintillation medium. The asymmetric nature of the scattering between a neutron and a deuterium in the center of mass produces a pulse-height spectrum from the deuterated scintillator which contains useful information on the initial energy of the neutron. Work supported in part by the State of Florida and NSF Grant No. 1401574.

  18. Development of a unit cell for a Ge:Ga detector array

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Two modules of gallium-doped germanium (Ge:Ga) infrared detectors with integrated multiplexing readouts and supporting drive electronics were designed and tested. This development investigated the feasibility of producing two-dimensional Ge:Ga arrays by stacking linear modules in a housing capable of providing uniaxial stress for enhanced long-wavelength response. Each module includes 8 detectors (1x1x2 mm) mounted to a sapphire board. The element spacing is 12 microns. The back faces of the detector elements are beveled with an 18 deg angle, which was proved to significantly enhance optical absorption. Each module includes a different silicon metal-oxide semiconductor field effect transistor (MOSFET) readout. The first circuit was built from discrete MOSFET components; the second incorporated devices taken from low-temperature integrated circuit multiplexers. The latter circuit exhibited much lower stray capacitance and improved stability. Using these switched-FET circuits, it was demonstrated that burst readout, with multiplexer active only during the readout period, could successfully be implemented at approximately 3.5 K.

  19. Intensity information extraction in Geiger mode detector array based three-dimensional imaging applications

    NASA Astrophysics Data System (ADS)

    Wang, Fei

    2013-09-01

    Geiger-mode detectors have single photon sensitivity and picoseconds timing resolution, which make it a good candidate for low light level ranging applications, especially in the case of flash three dimensional imaging applications where the received laser power is extremely limited. Another advantage of Geiger-mode APD is their capability of large output current which can drive CMOS timing circuit directly, which means that larger format focal plane arrays can be easily fabricated using the mature CMOS technology. However Geiger-mode detector based FPAs can only measure the range information of a scene but not the reflectivity. Reflectivity is a major characteristic which can help target classification and identification. According to Poisson statistic nature, detection probability is tightly connected to the incident number of photon. Employing this relation, a signal intensity estimation method based on probability inversion is proposed. Instead of measuring intensity directly, several detections are conducted, then the detection probability is obtained and the intensity is estimated using this method. The relation between the estimator's accuracy, measuring range and number of detections are discussed based on statistical theory. Finally Monte-Carlo simulation is conducted to verify the correctness of this theory. Using 100 times of detection, signal intensity equal to 4.6 photons per detection can be measured using this method. With slight modification of measuring strategy, intensity information can be obtained using current Geiger-mode detector based FPAs, which can enrich the information acquired and broaden the application field of current technology.

  20. Photoconductive terahertz near-field detector with a hybrid nanoantenna array cavity

    SciTech Connect

    Mitrofanov, Oleg; Brener, Igal; Luk, Ting S.; Reno, John L.

    2015-11-19

    Nanoscale structuring of optical materials leads to modification of their properties and can be used for improving efficiencies of photonic devices and for enabling new functionalities. In ultrafast optoelectronic switches for generation and detection of terahertz (THz) radiation, incorporation of nanostructures allows us to overcome inherent limitations of photoconductive materials. We propose and demonstrate a nanostructured photoconductive THz detector for sampling highly localized THz fields, down to the level of λ/150. The nanostructure that consists of an array of optical nanoantennas and a distributed Bragg reflector forms a hybrid cavity, which traps optical gate pulses within the photoconductive layer. The effect of photon trapping is observed as enhanced absorption at a designed wavelength. This optically thin photoconductive THz detector allows us to detect highly confined evanescent THz fields coupled through a deeply subwavelength aperture as small as 2 μm (λ/150 at 1 THz). As a result, by monolithically integrating the THz detector with apertures ranging from 2 to 5 μm we realize higher spatial resolution and higher sensitivity in aperture-type THz near-field microscopy and THz time-domain spectroscopy.

  1. SU-E-P-24: Simplified EDW Profile Measurements Using Two Commonly Available Detector Arrays

    SciTech Connect

    Reynolds, T; Arentsen, L; Watanabe, Y; Alaei, P

    2015-06-15

    Purpose: Enhanced dynamic wedge (EDW) profiles are needed as part of the commissioning of a treatment planning system. This work compares the acquisition of EDW profiles using a linear diode array (LDA) with two commonly used detector arrays available in the clinics, with the goal of identifying the simplest approach for these measurements. Methods: The measurements of EDW profiles were performed on a Varian TrueBeam linear accelerator for 6, 10, and 18 MV photon beams for all seven wedge angles at four depths. The measurements were done using the LDA 99 in Blue Phantom2 (IBA Dosimetry), and IC Profiler and MapCHECK2 (Sun Nuclear) in solid water phantoms. The water phantom was set up at 100 cm SSD, whereas the two other devices were set up at 75 cm due to the size limitations of the devices. The largest possible field size was used. The average and maximum percentage differences were examined within the central 90% of the field and in the penumbra. Results: Dose profiles measured with IC Profiler were in a good agreement with LDA 99 data. The average percentage difference within the field did not exceed 0.5% for all energies. MapCHECK2 measurements matched well with LDA 99 for 10 and 18 MV (within 0.3%) with discrepancies of up to 1.4% observed for the 6 MV beam. The maximum percentage differences for both devices in the penumbra exhibited larger variations than LDA 99 results due to differences in detector spacing and high dose gradient, as expected. Conclusion: Common linac QA devices such as IC Profiler or MapCHECK2 provide EDW beam profile data of reasonable accuracy as compared to measurements performed using a linear diode array in a water phantom, saving the expense and time involved in acquiring and setting up a LDA.

  2. Performance of an X-ray imaging detector based on a structured scintillator

    NASA Astrophysics Data System (ADS)

    Svenonius, Olof; Sahlholm, Anna; Wiklund, Per; Linnros, Jan

    2009-08-01

    Structured scintillator plates have been fabricated by filling thallium-doped caesium iodide (CsI) into a silicon pore array. Their X-ray imaging properties have been characterized using a standard dental X-ray source and a charge coupled device (CCD) detector. Results indicate that finer structured pore arrays provide superior imaging resolution while their light output is lower. Direct absorption of X-ray quanta in the CCD is a significant contributor of detector noise. This can be avoided by using a thick fibre optic plate or, in certain cases, by using a hot-pixel software algorithm.

  3. High-performance SPAD array detectors for parallel photon timing applications

    NASA Astrophysics Data System (ADS)

    Rech, I.; Cuccato, A.; Antonioli, S.; Cammi, C.; Gulinatti, A.; Ghioni, M.

    2012-02-01

    Over the past few years there has been a growing interest in monolithic arrays of single photon avalanche diodes (SPAD) for spatially resolved detection of faint ultrafast optical signals. SPADs implemented in planar technologies offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency than PMTs and are able to provide, beside sensitivities down to single-photons, very high acquisition speeds. In order to make SPAD array more and more competitive in time-resolved application it is necessary to face problems like electrical crosstalk between adjacent pixel, moreover all the singlephoton timing electronics with picosecond resolution has to be developed. In this paper we present a new instrument suitable for single-photon imaging applications and made up of 32 timeresolved parallel channels. The 32x1 pixel array that includes SPAD detectors represents the system core, and an embedded data elaboration unit performs on-board data processing for single-photon counting applications. Photontiming information is exported through a custom parallel cable that can be connected to an external multichannel TCSPC system.

  4. Fabrication of 721-pixel silicon lens array of a microwave kinetic inductance detector camera

    NASA Astrophysics Data System (ADS)

    Mitsui, Kenji; Nitta, Tom; Okada, Norio; Sekimoto, Yutaro; Karatsu, Kenichi; Sekiguchi, Shigeyuki; Sekine, Masakazu; Noguchi, Takashi

    2015-04-01

    We have been developed a lens-integrated superconducting camera for millimeter and submillimeter astronomy. High-purity silicon (Si) is suitable for the lens array of the microwave kinetic inductance detector camera due to its high refractive index and low dielectric loss at low temperatures. The camera is an antenna-coupled Al coplanar waveguide on a Si substrate. Thus the lens and the device are made of the same material. We report a fabrication method of a 721-pixel Si lens array with an antireflection (AR) coating. The Si lens array was fabricated with an ultraprecision cutting machine. It uses TiAlN-coated carbide end mills attached with a high-speed spindle. The shape accuracy was less than 50 μm peak-to-valley and the surface roughness was arithmetic average roughness (Ra) of 1.8 μm. The mixed epoxy was used as an AR coating to adjust the refractive index. It was shaved to yield a thickness of 185 μm for 220 GHz. Narrow grooves were made between the lenses to prevent cracking due to the different thermal expansion coefficients of Si and the epoxy. The surface roughness of the AR coating was Ra of 2.4 to 4.2 μm.

  5. A 2×2 array of EMCCD-based solid state x-ray detectors.

    PubMed

    Sharma, P; Swetadri Vasan, S N; Titus, A H; Cartwright, A N; Bednarek, D R; Rudin, S

    2012-01-01

    We have designed and developed a new solid-state x-ray imaging system that consists of a 2×2 array of electron multiplying charge coupled devices (EMCCDs). This system is intended for fluoroscopic and angiographic medical imaging. The key components are the four 1024 × 1024 pixel EMCCDs with a pixel size of 13 × 13 µm(2). Each EMCCD is bonded to a fiber optic plate (FOP), and optically coupled to a 350 µm thick micro-columnar CsI(TI) scintillator via a 3.22∶1 fiber optic taper (FOT). The detector provides x-ray images of 9 line pairs/mm resolution at 15 frames/sec and real-time live video at 30 frames/sec with binning at a lower resolution, independent of the electronic gain applied to the EMCCD. The total field of view (FOV) of the array is 8.45 cm × 8.45 cm. The system is designed to also provide the ability to do region-of- interest imaging (ROI) by selectively enabling individual modules of the array.

  6. A new DOI detector design using discrete crystal array with depth-dependent reflector patterns and single-ended readout

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Jae; Lee, Chaeyeong; Kang, Jihoon; Chung, Yong Hyun

    2017-01-01

    We developed a depth of interaction (DOI) positron emission tomography (PET) detector using depth-dependent reflector patterns in a discrete crystal array. Due to the different reflector patterns at depth, light distribution was changed relative to depth. As a preliminary experiment, we measured DOI detector module crystal identification performance. The crystal consisted of a 9×9 array of 2 mmx2 mmx20 mm lutetium-yttrium oxyorthosilicate (LYSO) crystals. The crystal array was optically coupled to a 64-channel position-sensitive photomultiplier tube with a 2 mmx2 mm anode size and an 18.1 mmx18.1 mm effective area. We obtained the flood image with an Anger-type calculation. DOI layers and 9×9 pixels were well distinguished in the obtained images. Preclinical PET scanners based on this detector design offer the prospect of high and uniform spatial resolution.

  7. 1024 × 1024 Si:As IBC detector arrays for JWST MIRI

    NASA Astrophysics Data System (ADS)

    Love, Peter J.; Hoffman, Alan W.; Lum, Nancy A.; Ando, Ken J.; Rosbeck, Joe; Ritchie, William D.; Therrien, Neil J.; Holcombe, Roger S.; Corrales, Elizabeth

    2005-08-01

    1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by RVS for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). MIRI provides imaging, coronagraphy, and low and medium resolution spectroscopy over the 5 - 28 μm band. The IBC devices are also suitable for other low-background applications. The Si:As IBC detectors have a pixel dimension of 25 μm and respond to infrared radiation between 5 and 28 μm, covering an important Mid-IR region beyond the 1 - 5 μm range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer Mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. We describe results of the development of a new 1024 × 1024 Si:As IBC array that responds with high quantum efficiency over the wavelength range 5 to 28 μm. The previous generation's largest, most sensitive infrared (IR) detectors at these wavelengths were the 256 × 256 / 30 μm pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument1. Detector performance results will be discussed, including relative spectral response, Responsive Quantum Efficiency (RQE) vs. detector bias, and dark current versus temperature. In addition, Sensor Chip Assembly (SCA) data will be presented from the first Engineering SCAs. The detector ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 105 electrons. The read noise of the "bare" MUX is less than 12 e- rms with Fowler-8 sampling at an operating temperature of 7 K. A companion paper by Craig McMurtry (University of Rochester) will discuss the details of SB305 MUX noise measurements2. Other features of the IBC array include 4 video outputs and a separate reference output with a frame rate of 0.36 Hz (2.75 sec frame time). Power dissipation is about 0.5 mW at a 0.36 Hz frame rate

  8. Electronics and data acquisition system of the extensive air shower detector array at the University of Puebla

    NASA Astrophysics Data System (ADS)

    Perez, E.; Salazar, H.; Villasenor, L.; Martinez, O.; Conde, R.; Murrieta, T.

    Field programmable gate arrays (FPGAs) are playing an increasing role in DAQ systems in cosmic ray experiments due to their high speed and integration and their low cost and low power comsumption. In this paper we describe in detail the new electronics and data acquisition system based on FPGA boards of the extensive air shower detector array built in the Campus of the University of Puebla. The purpose of this detector array is to measure the energy and arrival direction of primary cosmic rays with energies around 1015 eV. The array consists of 10 liquid scintillator detectors and 6 water Cherenkov detectors (of 1.86 m2 cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m2. The electronics described also makes use of analog to digital converters with a resolution of 10 bits and sampling speeds of 100 MS/s to digitize the PMT signals. We also discuss the advantages of discriminating the PMT signals inside the FPGAs with respect to the conventional use of dedicated discrimination circuits.

  9. Signal-Conditioning Block of a 1 × 200 CMOS Detector Array for a Terahertz Real-Time Imaging System

    PubMed Central

    Yang, Jong-Ryul; Lee, Woo-Jae; Han, Seong-Tae

    2016-01-01

    A signal conditioning block of a 1 × 200 Complementary Metal-Oxide-Semiconductor (CMOS) detector array is proposed to be employed with a real-time 0.2 THz imaging system for inspecting large areas. The plasmonic CMOS detector array whose pixel size including an integrated antenna is comparable to the wavelength of the THz wave for the imaging system, inevitably carries wide pixel-to-pixel variation. To make the variant outputs from the array uniform, the proposed signal conditioning block calibrates the responsivity of each pixel by controlling the gate bias of each detector and the voltage gain of the lock-in amplifiers in the block. The gate bias of each detector is modulated to 1 MHz to improve the signal-to-noise ratio of the imaging system via the electrical modulation by the conditioning block. In addition, direct current (DC) offsets of the detectors in the array are cancelled by initializing the output voltage level from the block. Real-time imaging using the proposed signal conditioning block is demonstrated by obtaining images at the rate of 19.2 frame-per-sec of an object moving on the conveyor belt with a scan width of 20 cm and a scan speed of 25 cm/s. PMID:26950128

  10. Signal-Conditioning Block of a 1 × 200 CMOS Detector Array for a Terahertz Real-Time Imaging System.

    PubMed

    Yang, Jong-Ryul; Lee, Woo-Jae; Han, Seong-Tae

    2016-03-02

    A signal conditioning block of a 1 × 200 Complementary Metal-Oxide-Semiconductor (CMOS) detector array is proposed to be employed with a real-time 0.2 THz imaging system for inspecting large areas. The plasmonic CMOS detector array whose pixel size including an integrated antenna is comparable to the wavelength of the THz wave for the imaging system, inevitably carries wide pixel-to-pixel variation. To make the variant outputs from the array uniform, the proposed signal conditioning block calibrates the responsivity of each pixel by controlling the gate bias of each detector and the voltage gain of the lock-in amplifiers in the block. The gate bias of each detector is modulated to 1 MHz to improve the signal-to-noise ratio of the imaging system via the electrical modulation by the conditioning block. In addition, direct current (DC) offsets of the detectors in the array are cancelled by initializing the output voltage level from the block. Real-time imaging using the proposed signal conditioning block is demonstrated by obtaining images at the rate of 19.2 frame-per-sec of an object moving on the conveyor belt with a scan width of 20 cm and a scan speed of 25 cm/s.

  11. Coherent summation of spatially distorted laser Doppler signals by using a two-dimensional heterodyne detector array

    NASA Technical Reports Server (NTRS)

    Chan, Kin P.; Killinger, Dennis K.

    1992-01-01

    Phase-sensitive coherent summation of individual heterodyne detector array signals was demonstrated for the enhanced detection of spatially distorted laser Doppler returns. With the use of a 2 x 2 heterodyne detector array, the phase and amplitude of a time-varying speckle pattern was detected, and the signal-to-noise ratio of the Doppler shift estimate was shown to be improved by a factor of 2, depending on the extent of spatial coherence loss. These results are shown to agree with a first-order analysis and indicate the advantage of coherent summation for both short-range laser Doppler velocimetry and long-range atmospheric coherent lidar.

  12. Linear charge coupled device detector array for imaging light propagating in an integrated thin-film optical waveguide

    NASA Technical Reports Server (NTRS)

    Chen, C. L.; Boyd, J. T.

    1976-01-01

    Device design, fabrication, and operation of a linear charge coupled device (CCD) detector array integrated with a thin film optical waveguide and applications of this structure to integrated optical signal processing and fiber optical communications were discussed. A two phase, overlapping-gate CCD is connected in parallel by means of a series of gates to an array of photodiodes. The photodiode provides an electrode free surface region so that a highly efficient waveguide detector coupling technique can be implemented. A thermally-oxidized layer of SiO2 forms an effective substrate for the optical waveguide.

  13. Performance characteristics of the new detector array for the SANS2d instrument on the ISIS spallation neutron source

    NASA Astrophysics Data System (ADS)

    Duxbury, D.; Heenan, R.; McPhail, D.; Raspino, D.; Rhodes, N.; Rogers, S.; Schooneveld, E.; Spill, E.; Terry, A.

    2014-12-01

    The performance of the new position sensitive neutron detector arrays of the Small Angle Neutron Scattering (SANS) instrument SANS2d is described. The SANS2d instrument is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source. Since the instrument became operational in 2009 it has used two one metre square multi-wire proportional detectors (MWPC). However, these detectors suffer from a low count rate capability, are easily damaged by excess beam and are then expensive to repair. The new detector arrays each consist of 120 individual position sensitive detector tubes, filled with 15 bar of 3He. Each of the tubes is one metre long and has a diameter of 8mm giving a detector array with an overall area of one square metre. Two such arrays have been built and installed in the SANS2d vacuum tank where they are currently taking user data. For SANS measurements operation of the detector within a vacuum is essential in order to reduce air scattering. A novel, fully engineered approach has been utilised to ensure that the high voltage connections and preamps are located inside the SANS2d vacuum tank at atmospheric pressure, within air tubes and air boxes respectively. The signal processing electronics and data acquisition system are located remotely in a counting house outside of the blockhouse. This allows easy access for maintenance purposes, without the need to remove the detectors from the vacuum tank. The design will be described in detail. A position resolution of 8mm FWHM or less has been measured along the length of the tubes. The initial measurements taken from a standard sample indicate that whilst the detector arrays themselves only represent a moderate improvement in overall detection efficiency (~ 20%), compared to the previous detector, the count rate capability is increased by a factor of 100. A significant advantage of the new array is the ability to change a single tube in situ

  14. SiPM detectors for the ASTRI project in the framework of the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Billotta, Sergio; Marano, Davide; Bonanno, Giovanni; Belluso, Massimiliano; Grillo, Alessandro; Garozzo, Salvatore; Romeo, Giuseppe; Timpanaro, Maria Cristina; Maccarone, Maria Concetta C.; Catalano, Osvaldo; La Rosa, Giovanni; Sottile, Giuseppe; Impiombato, Domenico; Gargano, Carmelo; Giarrusso, Salavtore

    2014-07-01

    The Cherenkov Telescope Array (CTA) is a worldwide new generation project aimed at realizing an array of a hundred ground based gamma-ray telescopes. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is the Italian project whose primary target is the development of an end-to-end prototype, named ASTRI SST-2M, of the CTA small size class of telescopes devoted to investigation of the highest energy region, from 1 to 100 TeV. Next target is the implementation of an ASTRI/CTA mini-array based on seven identical telescopes. Silicon Photo-Multipliers (SiPMs) are the semiconductor photosensor devices designated to constitute the camera detection system at the focal plane of the ASTRI telescopes. SiPM photosensors are suitable for the detection of the Cherenkov flashes, since they are very fast and sensitive to the light in the 300-700nm wavelength spectrum. Their drawbacks compared to the traditional photomultiplier tubes are high dark count rates, after-pulsing and optical cross-talk contributions, and intrinsic gains strongly dependent on temperature. Nonetheless, for a single pixel, the dark count rate is well below the Night Sky Background, the effects of cross-talk and afterpulses are typically lower than 20%, and the gain can be kept stable against temperature variations by means of adequate bias voltage compensation strategies. This work presents and discusses some experimental results from a large set of measurements performed on the SiPM sensors to be used for the ASTRI SST-2M prototype camera and on recently developed detectors demonstrating outstanding performance for the future evolution of the project in the ASTRI/CTA mini-array.

  15. Large arrays of dual-polarized multichroic TES detectors for CMB measurements with the SPT-3G receiver

    NASA Astrophysics Data System (ADS)

    Posada, Chrystian M.; Ade, Peter A. R.; Anderson, Adam J.; Avva, Jessica; Ahmed, Zeeshan; Arnold, Kam S.; Austermann, Jason; Bender, Amy N.; Benson, Bradford A.; Bleem, Lindsey; Byrum, Karen; Carlstrom, John E.; Carter, Faustin W.; Chang, Clarence; Cho, Hsiao-Mei; Cukierman, Ari; Czaplewski, David A.; Ding, Junjia; Divan, Ralu N. S.; de Haan, Tijmen; Dobbs, Matt; Dutcher, Daniel; Everett, Wenderline; Gannon, Renae N.; Guyser, Robert J.; Halverson, Nils W.; Harrington, Nicholas L.; Hattori, Kaori; Henning, Jason W.; Hilton, Gene C.; Holzapfel, William L.; Huang, Nicholas; Irwin, Kent D.; Jeong, Oliver; Khaire, Trupti; Korman, Milo; Kubik, Donna L.; Kuo, Chao-Lin; Lee, Adrian T.; Leitch, Erik M.; Lendinez Escudero, Sergi; Meyer, Stephan S.; Miller, Christina S.; Montgomery, Joshua; Nadolski, Andrew; Natoli, Tyler J.; Nguyen, Hogan; Novosad, Valentyn; Padin, Stephen; Pan, Zhaodi; Pearson, John E.; Rahlin, Alexandra; Reichardt, Christian L.; Ruhl, John E.; Saliwanchik, Benjamin; Shirley, Ian; Sayre, James T.; Shariff, Jamil A.; Shirokoff, Erik D.; Stan, Liliana; Stark, Antony A.; Sobrin, Joshua; Story, Kyle; Suzuki, Aritoki; Tang, Qing Yang; Thakur, Ritoban B.; Thompson, Keith L.; Tucker, Carole E.; Vanderlinde, Keith; Vieira, Joaquin D.; Wang, Gensheng; Whitehorn, Nathan; Yefremenko, Volodymyr; Yoon, Ki Won

    2016-07-01

    Detectors for cosmic microwave background (CMB) experiments are now essentially background limited, so a straightforward alternative to improve sensitivity is to increase the number of detectors. Large arrays of multichroic pixels constitute an economical approach to increasing the number of detectors within a given focal plane area. Here, we present the fabrication of large arrays of dual-polarized multichroic transition-edge-sensor (TES) bolometers for the South Pole Telescope third-generation CMB receiver (SPT-3G). The complete SPT-3G receiver will have 2690 pixels, each with six detectors, allowing for individual measurement of three spectral bands (centered at 95 GHz, 150 GHz and 220 GHz) in two orthogonal polarizations. In total, the SPT-3G focal plane will have 16140 detectors. Each pixel is comprised of a broad-band sinuous antenna coupled to a niobium microstrip transmission line. In-line filters are used to define the different band-passes before the millimeter-wavelength signal is fed to the respective Ti/Au TES sensors. Detectors are read out using a 64x frequency domain multiplexing (fMux) scheme. The microfabrication of the SPT-3G detector arrays involves a total of 18 processes, including 13 lithography steps. Together with the fabrication process, the effect of processing on the Ti/Au TES's Tc is discussed. In addition, detectors fabricated with Ti/Au TES films with Tc between 400 mK 560 mK are presented and their thermal characteristics are evaluated. Optical characterization of the arrays is presented as well, indicating that the response of the detectors is in good agreement with the design values for all three spectral bands (95 GHz, 150 GHz, and 220 GHz). The measured optical efficiency of the detectors is between 0.3 and 0.8. Results discussed here are extracted from a batch of research of development wafers used to develop the baseline process for the fabrication of the arrays of detectors to be deployed with the SPT-3G receiver. Results from

  16. Performance of multiplexed Ge:Ga detector arrays in the far infrared

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam; Mccreight, Craig

    1990-01-01

    The performance of two multi-element, multiplexed Ge:Ga linear arrays under low-background conditions was investigated. The on-focal switching is accomplished by MOSFET switches, and the integrated charge is made available through MOSFET source followers. The tests were conducted at 106 microns, and the radiation on the detectors was confined to a spectral window 1.25 microns wide using a stack of cold filters. At 4.2 K, the highest responsivity was 584 A/W, the noise equivalent power was 1.0 x 10(exp -16) W/square root of Hz, and the read noise was 6100 electrons/sample. A detailed description of the test setup and procedure is presented.

  17. On the estimation of target depth using the single transmit multiple receive metal detector array

    NASA Astrophysics Data System (ADS)

    Ho, K. C.; Gader, P. D.

    2012-06-01

    This paper investigates the use of the Single Transmit Multiple Receive (STMR) metal detector (MD) array to estimate the depth of metal targets, such as 155mm shells. The depth estimation problem using MD has been investigated by a number of researchers and the processing was performed along the down-track. The proposed method takes a different approach by exploring the MD responses in cross-track to achieve the depth estimation. It is found that the normalized energy spread of the MD output is narrower for shallow targets and wider for deeper targets. Based on this observation, a method is derived to estimate the depth of a target. Experimental results from the data collected at an U.S. Army test site validate the performance of the proposed depth estimator.

  18. Development of a low-cost-high-sensitivity Compton camera using CsI (Tl) scintillators (γI)

    NASA Astrophysics Data System (ADS)

    Kagaya, M.; Katagiri, H.; Enomoto, R.; Hanafusa, R.; Hosokawa, M.; Itoh, Y.; Muraishi, H.; Nakayama, K.; Satoh, K.; Takeda, T.; Tanaka, M. M.; Uchida, T.; Watanabe, T.; Yanagita, S.; Yoshida, T.; Umehara, K.

    2015-12-01

    We have developed a novel low-cost gamma-ray imaging Compton camera γI that has a high detection efficiency. Our motivation for the development of this detector was to measure the arrival directions of gamma rays produced by radioactive nuclides that were released by the Fukushima Daiichi nuclear power plant accident in 2011. The detector comprises two arrays of inorganic scintillation detectors, which act as a scatterer and an absorber. Each array has eight scintillation detectors, each comprising a large CsI (Tl) scintillator cube of side 3.5 cm, which is inexpensive and has a good energy resolution. Energies deposited by the Compton scattered electrons and subsequent photoelectric absorption, measured by each scintillation counter, are used for image reconstruction. The angular resolution was found to be 3.5° after using an image-sharpening technique. With this angular resolution, we can resolve a 1 m2 radiation hot spot that is located at a distance of 10 m from the detector with a wide field of view of 1 sr. Moreover, the detection efficiency 0.68 cps/MBq at 1 m for 662 keV (7.6 cps/μSv/h) is sufficient for measuring low-level contamination (i.e., less than 1 μSv/h) corresponding to typical values in large areas of eastern Japan. In addition to the laboratory tests, the imaging capability of our detector was verified in various regions with dose rates less than 1 μSv/h (e.g., Fukushima city).

  19. Development of Multilayer Analyzer Array Detectors for X-ray Fluorescence at the Third Generation Synchrotron Source

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Rosenbaum, G.; Liu, R.; Liu, C.; Carmeli, C.; Bunker, G.; Fischer, D.

    2004-05-01

    The development of Multilayer Analyzer Array Detector (MAAD) for X-ray fluorescence eliminates the count rate limitation encountered with multi-element Ge detectors. A 24-element multilayer detector has been fabricated that is tunable in a large energy region. This detector has been operational for more than two years at the BioCAT Beamline of the Advanced Photon Source at Argonne National Laboratory. Here we report our recent progress in developing multilayer detectors working in lower energy regions, in particular, performance at Ca Kα fluorescence energy and test results at soft x-ray energies. The band width of the analyzer response is found to be 3-4% of the fluorescence energy. Namely, at the Ca Kα energy, the band width is 140 eV; it is reduced to about 60 eV at Al Kα fluorescence energy. The throughput of the detector in this energy region (1.5-3.6 KeV) is 20% to 30%. These results demonstrate the feasibility for constructing multilayer analyzer array detectors for use in the soft x-ray region.

  20. The angular dependence of a two dimensional monolithic detector array for dosimetry in small radiation fields

    NASA Astrophysics Data System (ADS)

    Stansook, N.; Petasecca, M.; Utitsarn, K.; Newall, M.; Metcalfe, P.; Carolan, M.; Lerch, M.; Rosenfeld, A. B.

    2017-01-01

    The purpose of this study is to investigate the directional dependence of a two dimensional monolithic detector array (M512) under 6 MV photon irradiation and to evaluate the effect of field size on angular dependence. Square fields of sizes: 3x3 cm2 and 10x10 cm2 were measured at the iso-centre of a cylindrical phantom. Beam angles with incidences from 00- 1800 in increments of 150 were used to investigate the central pixel angular response of M512, normalized to the pixel response for normal (0°) beam incidence. The angular response of the detector was compared to the response of EBT3 radiochromic film in the identical geometric orientation. The maximum angular dependence was observed at the angle 90°±15° to be -18.62% and -17.70% for the field sizes 3x3 cm2 and 10x10 cm2, respectively. The angular dependence of M512 showed no significant difference between field sizes of 3x3 cm2 and 10x10 cm2 (p>0.05). The maximum dose difference measured by the central pixel of M512 and EBT3 for all angles are -20% for 3x3 cm2 field size and -18.58% for the 10x10 cm2 field. The diode array’s size and packaging effects the angular response of the detector. The angular correction factor is necessary to apply to increase accuracy in dosimetry for arc treatment delivery.

  1. Effect of scattered electrons on the ‘Magic Plate’ transmission array detector response

    NASA Astrophysics Data System (ADS)

    Alrowaili, Z. A.; Lerch, M.; Petasecca, M.; Carolan, M.; Rosenfeld, A.

    2017-02-01

    Transmission type detectors can provide a measure of the energy fluence and if they are real-time systems that do not significantly attenuate the radiation beam have a distinct advantage over the current method as Quality Assurance (QA) could in principle be done during the actual patient treatment. The use of diode arrays in QA holds much promise due to real-time operation and feedback when compared to other methods e.g. films which are not real-time. The goal of this work is to describe the characterization of the radiation response of a silicon diode array called the Magic Plate (MP) when operated in transmission mode (MPTM). The response linearity of MPTM was excellent (R2=1). When the MP was placed in linac block tray position; the change in PDD at phantom surface (SSD 100 cm) for a 10 × 10 cm2 was -0.037 %, -0.178 % and -0.949 % for 6 MV, 10 MV and 18 MV beams. Therefore, MP does not provide a significant increase in skin dose to the patient and the percentage depth doses showed an excellent agreement with and without MPTM for 6 MV, 10 MV and 18 MV beams.

  2. Calibration Scheme for Large Kinetic Inductance Detector Arrays Based on Readout Frequency Response

    NASA Astrophysics Data System (ADS)

    Bisigello, L.; Yates, S. J. C.; Murugesan, V.; Baselmans, J. J. A.; Baryshev, A. M.

    2016-07-01

    Microwave kinetic inductance detector (MKID) provides a way to build large ground-based sub-mm instruments such as NIKA and A-MKID. For such instruments, therefore, it is important to understand and characterize the response to ensure good linearity and calibration over a wide dynamic range. We propose to use the MKID readout frequency response to determine the MKID responsivity to an input optical source power. A signal can be measured in a KID as a change in the phase of the readout signal with respect to the KID resonant circle. Fundamentally, this phase change is due to a shift in the KID resonance frequency, in turn due to a radiation induced change in the quasiparticle number in the superconducting resonator. We show that the shift in resonant frequency can be determined from the phase shift by using KID phase versus frequency dependence using a previously measured resonant frequency. Working in this calculated resonant frequency, we gain near linearity and constant calibration to a constant optical signal applied in a wide range of operating points on the resonance and readout powers. This calibration method has three particular advantages: first, it is fast enough to be used to calibrate large arrays, with pixel counts in the thousands of pixels; second, it is based on data that are already necessary to determine KID positions; third, it can be done without applying any optical source in front of the array.

  3. Device localization and dynamic scan plane selection using a wireless MRI detector array

    PubMed Central

    Riffe, Matthew J.; Yutzy, Stephen R.; Jiang, Yun; Twieg, Michael D.; Blumenthal, Colin J.; Hsu, Daniel P.; Pan, Li; Gilson, Wesley D.; Sunshine, Jeffrey L.; Flask, Christopher A.; Duerk, Jeffrey L.; Nakamoto, Dean; Gulani, Vikas; Griswold, Mark A.

    2013-01-01

    Purpose A prototype wireless guidance device using single sideband amplitude modulation (SSB) is presented for a 1.5T MRI system. Methods The device contained three fiducial markers each mounted to an independent receiver coil equipped with wireless SSB technology. Acquiring orthogonal projections of these markers determined the position and orientation of the device, which was used to define the scan plane for a subsequent image acquisition. Device localization and scan plane update required approximately 30 ms, so it could be interleaved with high temporal resolution imaging. Since the wireless device is used for localization and doesn’t require full imaging capability, the design of the SSB wireless system was simplified by allowing an asynchronous clock between the transmitter and receiver. Results When coupled to a high readout bandwidth, the error caused by the lack of a shared frequency reference was quantified to be less than one pixel (0.78 mm) in the projection acquisitions. Image-guidance with the prototype was demonstrated with a phantom where a needle was successfully guided to a target and contrast was delivered. Conclusion The feasibility of active tracking with a wireless detector array is demonstrated. Wireless arrays could be incorporated into devices to assist in image-guided procedures. PMID:23900921

  4. Examination of cotton fibers and common contaminants using an infrared microscope and a focal-plane array detector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The chemical imaging of cotton fibers and common contaminants in fibers is presented. Chemical imaging was performed with an infrared microscope equipped with a Focal-Plane Array (FPA) detector. Infrared spectroscopy can provide us with information on the structure and quality of cotton fibers. In a...

  5. Performance of new 8-inch photomultiplier tube used for the Tibet muon-detector array

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Huang, J.; Chen, D.; Zhai, L.-M.; Chen, X.; Hu, X.-B.; Lin, Y.-H.; Jin, H.-B.; Zhang, X.-Y.; Feng, C.-F.; Jia, H.-Y.; Zhou, X.-X.; Danzengluobu; Chen, T.-L.; Labaciren; Liu, M.-Y.; Gao, Q.; Zhaxiciren

    2016-06-01

    Since 2014, a new hybrid experiment consisting of a high-energy air-shower-core array (YAC-II), a high-density air-shower array (Tibet-III) and a large underground water-Cherenkov muon-detector array (MD) has been continued by the Tibet ASγ collaboration to measure the chemical composition of cosmic rays in the wide energy range including the ``knee''. In this experiment, YAC-II is used to select high energy core events induced by cosmic rays in the above energy region, while MD is used to estimate the type of nucleus of primary particles by measuring the number of muons contained in the air showers. However, the dynamic range of each MD cell is only 5 to 2000 photoelectrons (PEs) which is mainly designed for observation of high-energy celestial gamma rays. In order to obtain the primary proton, helium and iron spectra and their ``knee'' positions with energy up to 1016 eV, each of PMTs equipped to the MD cell is required to measure the number of photons capable of covering a wide dynamic range of 100-106 PEs according to Monte Carlo simulations. In this paper, we firstly compare the characteristic features between R5912-PMT made by Japan Hamamatsu and CR365-PMT made by Beijing Hamamatsu. If there exists no serious difference, we will then add two 8-inch-in-diameter PMTs to meet our requirements in each MD cell, which are responsible for the range of 100-10000 PEs and 2000-1000000 PEs, respectively. That is, MD cell is expected to be able to measure the number of muons over 6 orders of magnitudes.

  6. Dosimetric Characteristics of a Two-Dimensional Diode Array Detector Irradiated with Passively Scattered Proton Beams

    PubMed Central

    Liengsawangwong, Praimakorn; Sahoo, Nanayan; Ding, Xiaoning; Lii, MingFwu; Gillin, Michale T.; Zhu, Xiaorong Ronald

    2015-01-01

    Purpose: To evaluate the dosimetric characteristics of a two-dimensional (2D) diode array detector irradiated with passively scattered proton beams. Materials and Methods: A diode array detector, MapCHECK (Model 1175, Sun Nuclear, Melbourne, FL, USA) was characterized in passive-scattered proton beams. The relative sensitivity of the diodes and absolute dose calibration were determined using a 250 MeV beam. The pristine Bragg curves (PBCs) measured by MapCHECK diodes were compared with those of an ion chamber using a range shift method. The water-equivalent thickness (WET) of the diode array detector’s intrinsic buildup also was determined. The inverse square dependence, linearity, and other proton dosimetric quantities measured by MapCHECK were also compared with those of the ion chambers. The change in the absolute dose response of the MapCHECK as a function of accumulated radiation dose was used as an indicator of radiation damage to the diodes. 2D dose distribution with and without the compensator were measured and compared with the treatment planning system (TPS) calculations. Results: The WET of the MapCHECK diode’s buildup was determined to be 1.7 cm. The MapCHECK-measured PBC were virtually identical to those measured by a parallel-plate ion chamber for 160, 180, and 250 MeV proton beams. The inverse square results of the MapCHECK were within ±0.4% of the ion chamber results. The linearity of MapCHECK results was within 1% of those from the ion chamber as measured in the range between 10 and 300 MU. All other dosimetric quantities were within 1.3% of the ion chamber results. The 2D dose distributions for non-clinical fields without compensator and the patient treatment fields with the compensator were consistent with the TPS results. The absolute dose response of the MapCHECK was changed by 7.4% after an accumulated dose increased by 170 Gy. Conclusions: The MapCHECK is a convenient and useful tool for 2D dose distribution measurements using passively

  7. Design and development of hard x-ray imaging detector using scintillator and Si photomultiplier

    NASA Astrophysics Data System (ADS)

    Goyal, S. K.; Naik, Amisha P.; Mithun, N. P. S.; Vadawale, S. V.; Acharya, Y. B.; Patel, A. R.; Ladiya, T.; Devashrayee, Niranjan M.

    2016-07-01

    There are various astrophysical phenomena which are of great importance and interest such as stellar explosions, Gamma ray bursts etc. There is also a growing interest in exploring the celestial sources in hard X-rays. High sensitive instruments are essential to perform the detailed studies of these cosmic accelerators and explosions. Hard X-ray imaging detectors having high absorption efficiency and mm spatial resolution are the key requirements to locate the generation of these astrophysical phenomenon. We hereby present a detector module which consists of a single CsI scintillation detector of size 15 x 15 x 3 mm3. The photon readout is done using an array of Silicon Photomultipliers (SiPMs). SiPM is a new development in the field of photon detection and can be described as 2D array of small (hundreds of μm2) avalanche photodiodes. We have achieved a spatial resolution of 0.5 mm with our initial setup. By using the array of these detector modules, we can build the detector with a large sensitive area with a very high spatial resolution. This paper presents the experimental details for single detector module using CsI (Tl) scintillator and SiPM and also presents the preliminary results of energy and position measurement. The GEANT4 simulation has also been carried out for the same geometry.

  8. Room-temperature InGaAs detector arrays for 1.0 - 1.7 microns spectroscopy

    NASA Technical Reports Server (NTRS)

    Olsen, G. H.; Joshi, A. M.; Mykietyn, E.; Colosi, J.; Woodruff, K. M.

    1989-01-01

    Linear arrays of 256 element InGaAs detectors with 100 x 30 micron pixels were mounted in multiplexer packages and tested in an optical multichannel analyzer (OMA). Typical performance characteristics include dark current (-5V) of 400 picoamps and responsivities of 0.75 A/W (1.3 microns) and 0.14 A/W (0.85 microns). The 256 element exhibited a mean room-temperature dark current of under 400 picoamps when mounted in the OMA and a dynamic range over 11 bits (2000:1). Future applications, including room-temperature detector arrays for 2.5 microns and avalanche photodiode arrays for 1.0-1.7 microns, are discussed.

  9. Thermal and Cold Neutron Computed Tomography at the Los Alamos Neutron Scattering Center Using an Amorphous Silicon Detector Array

    SciTech Connect

    Claytor, T.N.; Schwab, M.J.; Farnum, E.H.; McDonald, T.E.; Summa, D.A.; Sheats, M.J.; Stupin, D.M.; Sievers, W.L.

    1998-07-19

    The use of the EG and G-Heimann RTM 128 or dpiX FS20 amorphous silicon (a-Si) detector array for thermal neutron radiography/computed tomography has proven to be a quick and efficient means of producing high quality digital radiographic images. The resolution, although not as good as film, is about 750 pm with the RTM and 127 pm with the dpiX array with a dynamic range in excess of 2,800. In many respects using an amorphous silicon detector is an improvement over other techniques such as imaging with a CCD camera, using a storage phosphor plate or film radiography. Unlike a CCD camera, which is highly susceptible to radiation damage, a-Si detectors can be placed in the beam directly behind the object under examination and do not require any special optics or turning mirrors. The amorphous silicon detector also allows enough data to be acquired to construct a digital image in just a few seconds (minimum gate time 40 ms) whereas film or storage plate exposures can take many minutes and then need to be digitized with a scanner. The flat panel can therefore acquire a complete 3D computed tomography data set in just a few tens of minutes. While a-Si detectors have been proposed for use in imaging neutron beams, this is the first reported implementation of such a detector for neutron imaging.

  10. Design, fabrication and testing of 17um pitch 640x480 uncooled infrared focal plane array detector

    NASA Astrophysics Data System (ADS)

    Jiang, Lijun; Liu, Haitao; Chi, Jiguang; Qian, Liangshan; Pan, Feng; Liu, Xiang

    2015-10-01

    Uncooled infrared focal plane array (UIRFPA) detectors are widely used in industrial thermography cameras, night vision goggles, thermal weapon sights, as well as automotive night vision systems. To meet the market requirement for smaller pixel pitch and higher resolution, we have developed a 17um pitch 640x480 UIRFPA detector. The detector is based on amorphous silicon (a-Si) microbolometer technology, the readout integrated circuit (ROIC) is designed and manufactured with 0.35um standard CMOS technology on 8 inch wafer, the microbolometer is fabricated monolithically on the ROIC using an unique surface micromachining process developed inside the company, the fabricated detector is vacuum packaged with hermetic metal package and tested. In this paper we present the design, fabrication and testing of the 17um 640x480 detector. The design trade-off of the detector ROIC and pixel micro-bridge structure will be discussed, by comparison the calculation and simulation to the testing results. The novel surface micromachining process using silicon sacrificial layer will be presented, which is more compatible with the CMOS process than the traditional process with polyimide sacrificial layer, and resulted in good processing stability and high fabrication yield. The performance of the detector is tested, with temperature equivalent temperature difference (NETD) less than 60mK at F/1 aperture, operability better than 99.5%. The results demonstrate that the detector can meet the requirements of most thermography and night vision applications.

  11. Design, development, characterization and qualification of infrared focal plane area array detectors for space-borne imaging applications

    NASA Astrophysics Data System (ADS)

    Jain, Ankur; Banerjee, Arup

    2016-05-01

    This paper discusses the design, development, characterization and qualification aspects of large format Infrared Focal Plane Arrays (IRFPA) required for panchromatic, multi-, hyper- and ultra-spectral imaging applications from a space-borne imager. Detection of feeble radiant flux from the intended target in narrow spectral bands requires a highly sensitive low noise sensor array with high well capacity. For this the photodiode arrays responsive in desired spectral band are grown using different growth techniques and flip-chip bonded with a suitable Si Read-out ICs (ROICs) for signal conditioning. IR detectors require cryogenic cooling to achieve background limited performance. Although passive radiative cooling is always the preferred choice of cooling in space, it is not suitable for cooling IRFPAs due to high thermal loads. To facilitate characterization of IRFPAs and cool them to desired cryogenic temperature, an Integrated Detector Dewar Cooler Assembly (IDDCA) is essential where the detector array sits over the cold tip of an active cooler and the detector cooler assembly is vacuum sealed in a thermally isolated Dewar. A cold shield above the sensor array inside the Dewar restricts its field-of-view and a cold filter fine tunes its spectral response. In this paper, various constituents of an IRFPA like sensor array materials, growth techniques, ROICs, filters, cold shields, cooling techniques etc., their types and selection criteria for different applications are discussed in detail. Design aspects of IRFPA characterization test bench, challenges involved in radiometric and spectral characterization and space qualification of such IDDCA based IRFPAs are also discussed.

  12. Development of megapixel HgCdTe detector arrays with 15 micron cutoff

    NASA Astrophysics Data System (ADS)

    Forrest, William J.; McMurtry, Craig W.; Dorn, Meghan L.; Pipher, Judith; Cabrera, Mario S.

    2016-06-01

    I. HistoryHgCdTe is a versatile II-VI semiconductor with a direct-bandgap tunable via the Hg:Cd ratio. Hg:Cd ratio = 53:47 (2.5 micron cutoff) was used on the NICMOS instrument on HST and the 2MASS. Increasing Hg:Cd ratio to 70:30 leads to a 5.4 micron cutoff, utilized in NEOWISE and many JWST instruments. Bailey, Wu et al. (1998) motivated extending this technology to 10 microns and beyond. Bacon, McMurtry et al. (2003, 2004) indicated significant progress toward this longwave (LW) goal.Warm-Spitzer has pioneered passive cooling to below 30 K in space, enabling the JWST mission.II. CurrentNASA's proposed NEOcam mission selected HgCdTe with a 10.6 micron cutoff because it promises natural Zodiacal background limited sensitivity with modest cooling (40 K). Teledyne Imaging Systems (TIS) is producing megapixel arrays with excellent performance (McMurtry, Lee, Dorn et al. (2013)) for this mission.III. FutureModest cooling requirements (circa 30 K) coupled with megapixel arrays and LW sensitivity in the thermal IR make HgCdTe attractive for many infrared instruments. For instance, the spectral signature of a terrestrial planet orbiting in the habitable zone of a nearby star will be the deep and wide absorption by CO_2 centered at 15 microns (Seager and Deming, 2010). LW instruments can enhance Solar System missions, such as exploration of the Enceladus geysers (Spencer, Buratti et al. 2006). Passive cooling will be adequate for these missions. Modern ground-based observatories will benefit from infrared capability out to the N band (7.5-13.6 microns). The required detector temperatures (30-40 K) are easily achievable using commercially available mechanical cryo-coolers (refrigerators).IV. Progress to dateTIS is developing megapixel HgCdTe arrays sensitive out to 15 microns under the direction of the University of Rochester. As a first step, we have produced arrays with a 13 micron cutoff. The initial measurements indicate very promising performance. We will present the

  13. Development of megapixel HgCdTe detector arrays with 15 micron cutoff

    NASA Astrophysics Data System (ADS)

    Forrest, William J.; McMurtry, Craig W.; Dorn, Meghan; Pipher, Judith; Cabrera, Mario S.

    2016-10-01

    I. HistoryHgCdTe is a versatile II-VI semiconductor with a direct-bandgap tunable via the Hg:Cd ratio. Hg:Cd ratio = 53:47 (2.5 micron cutoff) was used on the NICMOS instrument on HST and the 2MASS. Increasing Hg:Cd ratio to 70:30 leads to a 5.4 micron cutoff, utilized in NEOWISE and many JWST instruments. Bailey, Wu et al. (1998) motivated extending this technology to 10 microns and beyond. Bacon, McMurtry et al. (2003, 2004) indicated significant progress toward this longwave (LW) goal.Warm-Spitzer has pioneered passive cooling to below 30 K in space, enabling the JWST mission.II. CurrentNASA's proposed NEOcam mission selected HgCdTe with a 10.6 micron cutoff because it promises natural Zodiacal background limited sensitivity with modest cooling (40 K). Teledyne Imaging Systems (TIS) is producing megapixel arrays with excellent performance (McMurtry, Lee, Dorn et al. (2013)) for this mission.III. FutureModest cooling requirements (circa 30 K) coupled with megapixel arrays and LW sensitivity in the thermal IR make HgCdTe attractive for many infrared instruments. For instance, the spectral signature of a terrestrial planet orbiting in the habitable zone of a nearby star will be the deep and wide absorption by CO_2 centered at 15 microns (Seager and Deming, 2010). LW instruments can enhance Solar System missions, such as exploration of the Enceladus geysers (Spencer, Buratti et al. 2006). Passive cooling will be adequate for these missions. Modern ground-based observatories will benefit from infrared capability out to the N band (7.5-13.6 microns). The required detector temperatures (30-40 K) are easily achievable using commercially available mechanical cryo-coolers (refrigerators).IV. Progress to dateTIS is developing megapixel HgCdTe arrays sensitive out to 15 microns under the direction of the University of Rochester. As a first step, we have produced arrays with a 13 micron cutoff. The initial measurements indicate very promising performance. We will present the

  14. The design, implementation, and performance of the Atro-H SXS calorimeter array and anti-coincidence detector

    NASA Astrophysics Data System (ADS)

    Kilbourne, Caroline A.; Adams, Joseph S.; Brekosky, Regis P.; Chervenak, James A.; Chiao, Meng P.; Eckart, Megan E.; Figueroa-Feliciano, Enectali; Galeazzi, Massimiliano; Grein, Christoph; Jhabvala, Christine A.; Kelley, Richard L.; Kelly, Daniel P.; Leutenegger, Maurice A.; McCammon, Dan; Porter, F. S.; Szymkowiak, Andrew E.; Watanabe, Tomomi; Zhao, Jun

    2016-07-01

    The calorimeter array of the JAXA Astro-H (renamed Hitomi) Soft X-ray Spectrometer (SXS) was designed to provide unprecedented spectral resolution of spatially extended cosmic x-ray sources and of all cosmic x-ray sources in the Fe-K band around 6 keV, enabling essential plasma diagnostics. The SXS has a square array of 36 microcalorimeters at the focal plane. These calorimeters consist of ion-implanted silicon thermistors and HgTe thermalizing x-ray absorbers. These devices have demonstrated a resolution of better than 4.5 eV at 6 keV when operated at a heat-sink temperature of 50 mK. We will discuss the basic physical parameters of this array, including the array layout, thermal conductance of the link to the heat sink, resistance function, absorber details, and means of attaching the absorber to the thermistorbearing element. We will also present the thermal characterization of the whole array, including thermal conductance and crosstalk measurements and the results of pulsing the frame temperature via alpha particles, heat pulses, and the environmental background. A silicon ionization detector is located behind the calorimeter array and serves to reject events due to cosmic rays. We will briefly describe this anti-coincidence detector and its performance.

  15. The Design, Implementation, and Performance of the Astro-H SXS Calorimeter Array and Anti-Coincidence Detector

    NASA Technical Reports Server (NTRS)

    Kilbourne, Caroline A.; Adams, Joseph S.; Brekosky, Regis P.; Chiao, Meng P.; Chervenak, James A.; Eckart, Megan E.; Figueroa-Feliciano, Enectali; Galeazzi, Masimilliano; Grein, Christoph; Jhabvala, Christine A.; Kelley, Richard L.; Leutenegger, Maurice A.; McCammon, Dan; Porter, F. Scott; Szymkowiak, Andrew E.; Watanabe, Tomomi; Zhao, Jun

    2016-01-01

    The calorimeter array of the JAXA Astro-H (renamed Hitomi) Soft X-ray Spectrometer (SXS) was designed to provide unprecedented spectral resolution of spatially extended cosmic x-ray sources and of all cosmic x-ray sources in the Fe-K band around 6 keV, enabling essential plasma diagnostics. The SXS has a square array of 36 microcalorimeters at the focal plane. These calorimeters consist of ion-implanted silicon thermistors and HgTe thermalizing x-ray absorbers. These devices have demonstrated a resolution of better than 4.5 eV at 6 keV when operated at a heat-sink temperature of 50 mK. We will discuss the basic physical parameters of this array, including the array layout, thermal conductance of the link to the heat sink, resistance function, absorber details, and means of attaching the absorber to the thermistor-bearing element. We will also present the thermal characterization of the whole array, including thermal conductance and crosstalk measurements and the results of pulsing the frame temperature via alpha particles, heat pulses, and the environmental background. A silicon ionization detector is located behind the calorimeter array and serves to reject events due to cosmic rays. We will briefly describe this anti-coincidence detector and its performance.

  16. Optical theory of partially coherent thin-film energy-absorbing structures for power detectors and imaging arrays.

    PubMed

    Withington, Stafford; Thomas, Christopher N

    2009-06-01

    Free-space power detectors often have energy absorbing structures comprising multilayer systems of patterned thin films. We show that for any system of interacting resistive films, the expectation value of the absorbed power is given by the contraction of two tensor fields: one describes the spatial state of coherence of the incoming radiation, the other the state of coherence to which the detector is sensitive. Equivalently, the natural modes of the optical field scatter power into the natural modes of the detector. We describe a procedure for determining the amplitude, phase, and polarization patterns of a detector's optical modes and their relative responsivities. The procedure gives the state of coherence of the currents flowing in the system and leads to important conceptual insights into the way the pixels of an imaging array interact and extract information from an optical field.

  17. Design and initial performance of the Askaryan Radio Array prototype EeV neutrino detector at the South Pole

    NASA Astrophysics Data System (ADS)

    Ara Collaboration; Allison, P.; Auffenberg, J.; Bard, R.; Beatty, J. J.; Besson, D. Z.; Böser, S.; Chen, C.; Chen, P.; Connolly, A.; Davies, J.; Duvernois, M.; Fox, B.; Gorham, P. W.; Grashorn, E. W.; Hanson, K.; Haugen, J.; Helbing, K.; Hill, B.; Hoffman, K. D.; Hong, E.; Huang, M.; Huang, M. H. A.; Ishihara, A.; Karle, A.; Kennedy, D.; Landsman, H.; Liu, T. C.; Macchiarulo, L.; Mase, K.; Meures, T.; Meyhandan, R.; Miki, C.; Morse, R.; Newcomb, M.; Nichol, R. J.; Ratzlaff, K.; Richman, M.; Ritter, L.; Rott, C.; Rotter, B.; Sandstrom, P.; Seckel, D.; Touart, J.; Varner, G. S.; Wang, M.-Z.; Weaver, C.; Wendorff, A.; Yoshida, S.; Young, R.

    2012-02-01

    We report on studies of the viability and sensitivity of the Askaryan Radio Array (ARA), a new initiative to develop a Teraton-scale ultra-high energy neutrino detector in deep, radio-transparent ice near Amundsen-Scott station at the South Pole. An initial prototype ARA detector system was installed in January 2011, and has been operating continuously since then. We describe measurements of the background radio noise levels, the radio clarity of the ice, and the estimated sensitivity of the planned ARA array given these results, based on the first five months of operation. Anthropogenic radio interference in the vicinity of the South Pole currently leads to a few-percent loss of data, but no overall effect on the background noise levels, which are dominated by the thermal noise floor of the cold polar ice, and galactic noise at lower frequencies. We have also successfully detected signals originating from a 2.5 km deep impulse generator at a distance of over 3 km from our prototype detector, confirming prior estimates of kilometer-scale attenuation lengths for cold polar ice. These are also the first such measurements for propagation over such large slant distances in ice. Based on these data, ARA-37, the ˜200 km2 array now in its initial construction phase, will achieve the highest sensitivity of any planned or existing neutrino detector in the 1016-1019 eV energy range.

  18. Two-dimensional focal plane detector arrays for LWIR/VLWIR space and airborne sounding missions

    NASA Astrophysics Data System (ADS)

    Hanna, S.; Bauer, A.; Bitterlich, H.; Bruder, M.; Haas, L.-D.; Haiml, M.; Hofmann, K.; Mahlein, K.-M.; Nothaft, H.-P.; Schallenberg, T.; Weber, A.; Wendler, J.; Wollrab, R.; Ziegler, J.

    2010-10-01

    An increasing need for high-precision atmospheric data especially in the long wavelength infrared (LWIR) and very long wavelength infrared (VLWIR) spectral ranges has arisen in the past years not only for the analysis of climate change and its effect on the earth's ecosystem, but also for weather forecast and atmospheric monitoring purposes. Spatially and spectrally resolved atmospheric emission data are advantageously gathered through limb or nadir sounding using an imaging Fourier transform (FT) interferometer with a two-dimensional (2D) high-speed focal plane detector array (FPA). In this paper, AIM reports on its latest results on MCT VLWIR FPAs for Fourier transform infrared sounding applications in the 8-15μm spectral range. The performance of a (112x112) pixel photodiode array with a 40μm pixel pitch incorporating extrinsic p-doping for low dark current, a technique for linearity improvement at high photon fluxes, pixel guards, pixel select/de-select, and a (2x2) super-pixel architecture is discussed. The customized read-out integrated circuit (ROIC) supporting integrate while-read (IWR) operation has a buffered direct injection (BDI) input stage and a full well capacity (FWC) of 143 Megaelectrons per super-pixel. It consists of two independently operating halves with two analog video outputs each. The full frame rate is typically 4k frames/sec, making it suitable for use with rapid scan FT infrared spectrometers. At a 55K operating temperature and an ~14.4μm cut-off wavelength, a photo response of 12.1mV/K and a noise equivalent temperature difference of 24.8mK at half well filling are demonstrated for a 286K reference scene. The nonlinearity error is <0.5%.

  19. Study of radiation hardness of pure CsI crystals for Belle-II calorimeter

    NASA Astrophysics Data System (ADS)

    Boyarintsev, A.; Boyarintseva, Y.; Gektin, A.; Shiran, N.; Shlyakhturov, V.; Taranyuk, V.; Timoshenko, N.; Bobrov, A.; Garmash, A.; Golkovski, M.; Kuzmin, A.; Matvienko, D.; Savrovski, P.; Shebalin, V.; Shwartz, B.; Vinokurova, A.; Vorobyev, V.; Zhilich, V.; Krumshtein, Z. V.; Nozdrin, A. A.; Olshevsky, A. G.

    2016-03-01

    A study of the radiation hardness of pure CsI crystals 30 cm long was performed with a uniformly absorbed dose of up to 14.3 krad. This study was initiated by the proposed upgrade of the end cap calorimeter of the Belle-II detector, using pure CsI crystals. A set of 14 crystals of truncated pyramid shape used in this study was produced at the Institute for Scintillation Materials NAS from 14 different ingots grown with variations of the growing technology. Interrelationship of crystal scintillation characteristics, radiation hardness and the growing technology was observed.

  20. Core-shell diode array for high performance particle detectors and imaging sensors: status of the development

    NASA Astrophysics Data System (ADS)

    Jia, G.; Hübner, U.; Dellith, J.; Dellith, A.; Stolz, R.; Plentz, J.; Andrä, G.

    2017-02-01

    We propose a novel high performance radiation detector and imaging sensor by a ground-breaking core-shell diode array design. This novel core-shell diode array are expected to have superior performance respect to ultrahigh radiation hardness, high sensitivity, low power consumption, fast signal response and high spatial resolution simultaneously. These properties are highly desired in fundamental research such as high energy physics (HEP) at CERN, astronomy and future x-ray based protein crystallography at x-ray free electron laser (XFEL) etc.. This kind of detectors will provide solutions for these fundamental research fields currently limited by instrumentations. In this work, we report our progress on the development of core-shell diode array for the applications as high performance imaging sensors and particle detectors. We mainly present our results in the preparation of high aspect ratio regular silicon rods by metal assisted wet chemical etching technique. Nearly 200 μm deep and 2 μm width channels with high aspect ratio have been etched into silicon. This result will open many applications not only for the core-shell diode array, but also for a high density integration of 3D microelectronics devices.

  1. Detectors

    DOEpatents

    Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore; Bounds, John Alan; Allander, Krag

    2002-01-01

    The apparatus and method provide techniques through which both alpha and beta emission determinations can be made simultaneously using a simple detector structure. The technique uses a beta detector covered in an electrically conducting material, the electrically conducting material discharging ions generated by alpha emissions, and as a consequence providing a measure of those alpha emissions. The technique also offers improved mountings for alpha detectors and other forms of detectors against vibration and the consequential effects vibration has on measurement accuracy.

  2. Characterization of direct readout Si:Sb and Si:Ga infrared detector arrays for space-based astronomy

    NASA Technical Reports Server (NTRS)

    Mckelvey, Mark E.; Mccreight, Craig R.; Goebel, John H.; Moss, Nicolas N.; Savage, Maureen L.

    1988-01-01

    Preliminary test results from the evaluation of Si:Sb and Si:Ga 58 x 62-element infrared detector arrays are presented. These devices are being characterized under background conditions and readout rates representative of operation in orbiting, crogenically-cooled infrared observatories. The arrays are hybridized to silicon direct-readout multiplexers which allow random-access and nondestructive readout. Array performance optimization is being conducted with a flexible microcomputer-based drive and readoaut electronics system. Preliminary Si:Sb measurements indicate a sense node capacitance of 0.06 pF, peak (28-micron) responsivity above 3 A/W at 2V bias, read noise of 130 rms e(-), dark current approximately 10 e(-)/s, and a well capacity greater than 10 to the 5th e(-). The limited test data available on the performance of the Si:Ga array are also discussed.

  3. The VCSEL-based array optical transmitter (ATx) development towards 120-Gbps link for collider detector: development update

    NASA Astrophysics Data System (ADS)

    Guo, D.; Liu, C.; Chen, J.; Chramowicz, J.; Gong, D.; Hou, S.; Huang, D.; Jin, G.; Li, X.; Liu, T.; Prosser, A.; Teng, P. K.; Ye, J.; Zhou, Y.; You, Y.; Xiang, A. C.; Liang, H.

    2015-01-01

    A compact radiation-tolerant array optical transmitter module (ATx) is developed to provide data transmission up to 10Gbps per channel with 12 parallel channels for collider detector applications. The ATx integrates a Vertical Cavity Surface-Emitting Laser (VCSEL) array and driver circuitry for electrical to optical conversion, an edge warp substrate for the electrical interface and a micro-lens array for the optical interface. This paper reports the continuing development of the ATx custom package. A simple, high-accuracy and reliable active-alignment method for the optical coupling is introduced. The radiation-resistance of the optoelectronic components is evaluated and the inclusion of a custom-designed array driver is discussed.

  4. Update on the Fabrication and Performance of 2-D Arrays of Superconducting Magnesium Diboride (MgB2) Thermal Detectors for Outer-Planets Exploration

    NASA Technical Reports Server (NTRS)

    Lakew, Brook; Aslam, S.

    2011-01-01

    Detectors with better performance than the current thermopile detectors that operate at room temperature will be needed at the focal plane of far-infrared instruments on future planetary exploration missions. We will present an update on recent results from the 2-D array of MgB2 thermal detectors being currently developed at NASA Goddard. Noise and sensitivity results will be presented and compared to thermal detectors currently in use on planetary missions.

  5. Nonlinearity and image persistence of P-20 phosphor-based intensified photodiode array detectors used in CARS spectroscopy.

    PubMed

    Snelling, D R; Smallwood, G J; Sawchuk, R A

    1989-08-01

    Several self-scanning photodiode arrays (IPDA) used for CARS spectroscopy are shown to exhibit a greater image persistence than has generally been realized, and to exhibit a falloff in sensitivity that is logarithmic with decreasing output signal. These effects are attributed to the P-20 phosphor based intensifiers used in the IPDAs and are probably generic to all such detectors. A strategy for minimizing the image persistence in CARS spectroscopy is presented. A prototype detector incorporating a much faster rare earth phosphor is evaluated and shown to be more suited to single pulse CARS measurements in turbulent combustion than the IPDAs incorporating P-20 phosphors.

  6. Combining transverse field detectors and color filter arrays to improve multispectral imaging systems.

    PubMed

    Martínez, Miguel A; Valero, Eva M; Hernández-Andrés, Javier; Romero, Javier; Langfelder, Giacomo

    2014-05-01

    This work focuses on the improvement of a multispectral imaging sensor based on transverse field detectors (TFDs). We aimed to achieve a higher color and spectral accuracy in the estimation of spectral reflectances from sensor responses. Such an improvement was done by combining these recently developed silicon-based sensors with color filter arrays (CFAs). Consequently, we sacrificed the filter-less full spatial resolution property of TFDs to narrow down the spectrally broad sensitivities of these sensors. We designed and performed several experiments to test the influence of different design features on the estimation quality (type of sensor, tunability, interleaved polarization, use of CFAs, type of CFAs, number of shots), some of which are exclusive to TFDs. We compared systems that use a TFD with systems that use normal monochrome sensors, both combined with multispectral CFAs as well as common RGB filters present in commercial digital color cameras. Results showed that a system that combines TFDs and CFAs performs better than systems with the same type of multispectral CFA and other sensors, or even the same TFDs combined with different kinds of filters used in common imaging systems. We propose CFA+TFD-based systems with one or two shots, depending on the possibility of using longer capturing times or not. Improved TFD systems thus emerge as an interesting possibility for multispectral acquisition, which overcomes the limited accuracy found in previous studies.

  7. Evolution of miniature detectors and focal plane arrays for infrared sensors

    NASA Technical Reports Server (NTRS)

    Watts, Louis A.

    1993-01-01

    Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.

  8. Optofluidic holographic microscopy with custom field of view (FoV) using a linear array detector.

    PubMed

    Bianco, V; Paturzo, M; Marchesano, V; Gallotta, I; Di Schiavi, E; Ferraro, P

    2015-05-07

    Simple and effective imaging strategies are of utmost interest for applications on a lab-on-chip scale. In fact, the majority of diagnostic tools for medical as well as biotechnological studies still employ image-based approaches. Having onboard the chip a compact but powerful imaging apparatus with multiple imaging capabilities, such as 3D dynamic focusing along the optical axis, unlimited field of view (FoV) and double outputs, namely, intensity and quantitative phase-contrast maps of biological objects, is of extreme importance for the next generation of Lab-on-a-Chip (LoC) devices. Here we present a coherent 3D microscopy approach with a holographic modality that is specifically suitable for studying biological samples while they simply flow along microfluidic paths. The LoC device is equipped with a compact linear array detector to capture and generate a new conceptual type of a digital hologram in the space-time domain, named here as Space-Time Digital Hologram (STDH). The reported results show that the method is a promising diagnostic tool for optofluidic investigations of biological specimens.

  9. Evolution of miniature detectors and focal plane arrays for infrared sensors

    NASA Astrophysics Data System (ADS)

    Watts, Louis A.

    1993-06-01

    Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.

  10. Very low noise AC/DC power supply systems for large detector arrays.

    PubMed

    Arnaboldi, C; Baù, A; Carniti, P; Cassina, L; Giachero, A; Gotti, C; Maino, M; Passerini, A; Pessina, G

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μV(RMS) (CUORE setup) and 90 μV(RMS) (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

  11. The B AB AR detector

    NASA Astrophysics Data System (ADS)

    Aubert, B.; Bazan, A.; Boucham, A.; Boutigny, D.; De Bonis, I.; Favier, J.; Gaillard, J.-M.; Jeremie, A.; Karyotakis, Y.; Le Flour, T.; Lees, J. P.; Lieunard, S.; Petitpas, P.; Robbe, P.; Tisserand, V.; Zachariadou, K.; Palano, A.; Chen, G. P.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Reinertsen, P. L.; Stugu, B.; Abbott, B.; Abrams, G. S.; Amerman, L.; Borgland, A. W.; Breon, A. B.; Brown, D. N.; Button-Shafer, J.; Clark, A. R.; Dardin, S.; Day, C.; Dow, S. F.; Fan, Q.; Gaponenko, I.; Gill, M. S.; Goozen, F. R.; Gowdy, S. J.; Gritsan, A.; Groysman, Y.; Hernikl, C.; Jacobsen, R. G.; Jared, R. C.; Kadel, R. W.; Kadyk, J.; Karcher, A.; Kerth, L. T.; Kipnis, I.; Kluth, S.; Kral, J. F.; Lafever, R.; LeClerc, C.; Levi, M. E.; Lewis, S. A.; Lionberger, C.; Liu, T.; Long, M.; Luo, L.; Lynch, G.; Luft, P.; Mandelli, E.; Marino, M.; Marks, K.; Matuk, C.; Meyer, A. B.; Minor, R.; Mokhtarani, A.; Momayezi, M.; Nyman, M.; Oddone, P. J.; Ohnemus, J.; Oshatz, D.; Patton, S.; Pedrali-Noy, M.; Perazzo, A.; Peters, C.; Pope, W.; Pripstein, M.; Quarrie, D. R.; Rasson, J. E.; Roe, N. A.; Romosan, A.; Ronan, M. T.; Shelkov, V. G.; Stone, R.; Strother, P. D.; Telnov, A. V.; von der Lippe, H.; Weber, T. F.; Wenzel, W. A.; Zizka, G.; Bright-Thomas, P. G.; Hawkes, C. M.; Kirk, A.; Knowles, D. J.; O'Neale, S. W.; Watson, A. T.; Watson, N. K.; Deppermann, T.; Koch, H.; Krug, J.; Kunze, M.; Lewandowski, B.; Peters, K.; Schmuecker, H.; Steinke, M.; Andress, J. C.; Barlow, N. R.; Bhimji, W.; Chevalier, N.; Clark, P. J.; Cottingham, W. N.; De Groot, N.; Dyce, N.; Foster, B.; Mass, A.; McFall, J. D.; Wallom, D.; Wilson, F. F.; Abe, K.; Hearty, C.; McKenna, J. A.; Thiessen, D.; Camanzi, B.; Harrison, T. J.; McKemey, A. K.; Tinslay, J.; Antohin, E. I.; Blinov, V. E.; Bukin, A. D.; Bukin, D. A.; Buzykaev, A. R.; Dubrovin, M. S.; Golubev, V. B.; Ivanchenko, V. N.; Kolachev, G. M.; Korol, A. A.; Kravchenko, E. A.; Mikhailov, S. F.; Onuchin, A. P.; Salnikov, A. A.; Serednyakov, S. I.; Skovpen, Yu. I.; Telnov, V. I.; Yushkov, A. N.; Booth, J.; Lankford, A. J.; Mandelkern, M.; Pier, S.; Stoker, D. P.; Zioulas, G.; Ahsan, A.; Arisaka, K.; Buchanan, C.; Chun, S.; Faccini, R.; MacFarlane, D. B.; Prell, S. A.; Rahatlou, Sh.; Raven, G.; Sharma, V.; Burke, S.; Callahan, D.; Campagnari, C.; Dahmes, B.; Hale, D.; Hart, P. A.; Kuznetsova, N.; Kyre, S.; Levy, S. L.; Long, O.; Lu, A.; May, J.; Richman, J. D.; Verkerke, W.; Witherell, M.; Yellin, S.; Beringer, J.; DeWitt, J.; Dorfan, D. E.; Eisner, A. M.; Frey, A.; Grillo, A. A.; Grothe, M.; Heusch, C. A.; Johnson, R. P.; Kroeger, W.; Lockman, W. S.; Pulliam, T.; Rowe, W.; Sadrozinski, H.; Schalk, T.; Schmitz, R. E.; Schumm, B. A.; Seiden, A.; Spencer, E. N.; Turri, M.; Walkowiak, W.; Wilder, M.; Williams, D. C.; Chen, E.; Dubois-Felsmann, G. P.; Dvoretskii, A.; Hanson, J. E.; Hitlin, D. G.; Kolomensky, Yu. G.; Metzler, S.; Oyang, J.; Porter, F. C.; Ryd, A.; Samuel, A.; Weaver, M.; Yang, S.; Zhu, R. Y.; Devmal, S.; Geld, T. L.; Jayatilleke, S.; Jayatilleke, S. M.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P.; Broomer, B.; Erdos, E.; Fahey, S.; Ford, W. T.; Gaede, F.; van Hoek, W. C.; Johnson, D. R.; Michael, A. K.; Nauenberg, U.; Olivas, A.; Park, H.; Rankin, P.; Roy, J.; Sen, S.; Smith, J. G.; Wagner, D. L.; Blouw, J.; Harton, J. L.; Krishnamurthy, M.; Soffer, A.; Toki, W. H.; Warner, D. W.; Wilson, R. J.; Zhang, J.; Brandt, T.; Brose, J.; Dahlinger, G.; Dickopp, M.; Dubitzky, R. S.; Eckstein, P.; Futterschneider, H.; Kocian, M. L.; Krause, R.; Müller-Pfefferkorn, R.; Schubert, K. R.; Schwierz, R.; Spaan, B.; Wilden, L.; Behr, L.; Bernard, D.; Bonneaud, G. R.; Brochard, F.; Cohen-Tanugi, J.; Ferrag, S.; Fouque, G.; Gastaldi, F.; Matricon, P.; Mora de Freitas, P.; Renard, C.; Roussot, E.; T'Jampens, S.; Thiebaux, C.; Vasileiadis, G.; Verderi, M.; Anjomshoaa, A.; Bernet, R.; Di Lodovico, F.; Muheim, F.; Playfer, S.; Swain, J. E.; Falbo, M.; Bozzi, C.; Dittongo, S.; Folegani, M.; Piemontese, L.; Ramusino, A. C.; Treadwell, E.; Anulli, F.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Falciai, D.; Finocchiaro, G.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Xie, Y.; Zallo, A.; Bagnasco, S.; Buzzo, A.; Contri, R.; Crosetti, G.; Fabbricatore, P.; Farinon, S.; Lo Vetere, M.; Macri, M.; Minutoli, S.; Monge, M. R.; Musenich, R.; Pallavicini, M.; Parodi, R.; Passaggio, S.; Pastore, F. C.; Patrignani, C.; Pia, M. G.; Priano, C.; Robutti, E.; Santroni, A.; Bartoldus, R.; Dignan, T.; Hamilton, R.; Mallik, U.; Cochran, J.; Crawley, H. B.; Fischer, P. A.; Lamsa, J.; McKay, R.; Meyer, W. T.; Rosenberg, E. I.; Albert, J. N.; Beigbeder, C.; Benkebil, M.; Breton, D.; Cizeron, R.; Du, S.; Grosdidier, G.; Hast, C.; Höcker, A.; Lacker, H. M.; LePeltier, V.; Lutz, A. M.; Plaszczynski, S.; Schune, M. H.; Trincaz-Duvoid, S.; Truong, K.; Valassi, A.; Wormser, G.; Alford, O.; Behne, D.; Bionta, R. M.; Bowman, J.; Brigljević, V.; Brooks, A.; Dacosta, V. A.; Fackler, O.; Fujino, D.; Harper, M.; Lange, D. J.; Mugge, M.; O'Connor, T. G.; Olson, H.; Ott, L.; Parker, E.; Pedrotti, B.; Roeben, M.; Shi, X.; van Bibber, K.; Wenaus, T. J.; Wright, D. M.; Wuest, C. R.; Yamamoto, B.; Carroll, M.; Cooke, P.; Fry, J. R.; Gabathuler, E.; Gamet, R.; George, M.; Kay, M.; McMahon, S.; Muir, A.; Payne, D. J.; Sloane, R. J.; Sutcliffe, P.; Touramanis, C.; Aspinwall, M. L.; Bowerman, D. A.; Dauncey, P. D.; Eschrich, I.; Gunawardane, N. J. W.; Martin, R.; Nash, J. A.; Price, D. R.; Sanders, P.; Smith, D.; Azzopardi, D. E.; Back, J. J.; Dixon, P.; Harrison, P. F.; Newman-Coburn, D.; Potter, R. J. L.; Shorthouse, H. W.; Williams, M. I.; Vidal, P. B.; Cowan, G.; George, S.; Green, M. G.; Kurup, A.; Marker, C. E.; McGrath, P.; McMahon, T. R.; Salvatore, F.; Scott, I.; Vaitsas, G.; Brown, D.; Davis, C. L.; Li, Y.; Pavlovich, J.; Allison, J.; Barlow, R. J.; Boyd, J. T.; Fullwood, J.; Jackson, F.; Khan, A.; Lafferty, G. D.; Savvas, N.; Simopoulos, E. T.; Thompson, R. J.; Weatherall, J. H.; Bard, R.; Dallapiccola, C.; Farbin, A.; Jawahery, A.; Lillard, V.; Olsen, J.; Roberts, D. A.; Schieck, J. R.; Blaylock, G.; Flood, K. T.; Hertzbach, S. S.; Kofler, R.; Lin, C. S.; Willocq, S.; Wittlin, J.; Brau, B.; Cowan, R.; Taylor, F.; Yamamoto, R. K.; Britton, D. I.; Fernholz, R.; Houde, M.; Milek, M.; Patel, P. M.; Trischuk, J.; Lanni, F.; Palombo, F.; Bauer, J. M.; Booke, M.; Cremaldi, L.; Kroeger, R.; Reep, M.; Reidy, J.; Sanders, D. A.; Summers, D. J.; Arguin, J. F.; Beaulieu, M.; Martin, J. P.; Nief, J. Y.; Seitz, R.; Taras, P.; Woch, A.; Zacek, V.; Nicholson, H.; Sutton, C. S.; Cartaro, C.; Cavallo, N.; De Nardo, G.; Fabozzi, F.; Gatto, C.; Lista, L.; Piccolo, D.; Sciacca, C.; Cason, N. M.; LoSecco, J. M.; Alsmiller, J. R. G.; Gabriel, T. A.; Handler, T.; Heck, J.; Iwasaki, M.; Sinev, N. B.; Caracciolo, R.; Colecchia, F.; Dal Corso, F.; Galeazzi, F.; Marzolla, M.; Michelon, G.; Morandin, M.; Posocco, M.; Rotondo, M.; Santi, S.; Simonetto, F.; Stroili, R.; Torassa, E.; Voci, C.; Bailly, P.; Benayoun, M.; Briand, H.; Chauveau, J.; David, P.; De la Vaissière, C.; Del Buono, L.; Genat, J.-F.; Hamon, O.; Leruste, Ph.; Le Diberder, F.; Lebbolo, H.; Lory, J.; Martin, L.; Martinez-Vidal, F.; Roos, L.; Stark, J.; Versillé, S.; Zhang, B.; Manfredi, P. F.; Ratti, L.; Re, V.; Speziali, V.; Frank, E. D.; Gladney, L.; Guo, Q. H.; Panetta, J. H.; Angelini, C.; Batignani, G.; Bettarini, S.; Bondioli, M.; Bosi, F.; Carpinelli, M.; Forti, F.; Gaddi, A.; Gagliardi, D.; Giorgi, M. A.; Lusiani, A.; Mammini, P.; Morganti, M.; Morsani, F.; Neri, N.; Profeti, A.; Paoloni, E.; Raffaelli, F.; Rama, M.; Rizzo, G.; Sandrelli, F.; Simi, G.; Triggiani, G.; Haire, M.; Judd, D.; Paick, K.; Turnbull, L.; Wagoner, D. E.; Albert, J.; Bula, C.; Kelsey, M. H.; Lu, C.; McDonald, K. T.; Miftakov, V.; Sands, B.; Schaffner, S. F.; Smith, A. J. S.; Tumanov, A.; Varnes, E. W.; Bronzini, F.; Buccheri, A.; Bulfon, C.; Cavoto, G.; del Re, D.; Ferrarotto, F.; Ferroni, F.; Fratini, K.; Lamanna, E.; Leonardi, E.; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Safai Tehrani, F.; Serra, M.; Voena, C.; Waldi, R.; Jacques, P. F.; Kalelkar, M.; Plano, R. J.; Adye, T.; Claxton, B.; Dowdell, J.; Egede, U.; Franek, B.; Galagedera, S.; Geddes, N. I.; Gopal, G. P.; Kay, J.; Lidbury, J.; Madani, S.; Metcalfe, S.; Metcalfe, S.; Markey, G.; Olley, P.; Watt, M.; Xella, S. M.; Aleksan, R.; Besson, P.; Bourgeois, P.; Convert, P.; De Domenico, G.; de Lesquen, A.; Emery, S.; Gaidot, A.; Ganzhur, S. F.; Georgette, Z.; Gosset, L.; Graffin, P.; Hamel de Monchenault, G.; Hervé, S.; Karolak, M.; Kozanecki, W.; Langer, M.; London, G. W.; Marques, V.; Mayer, B.; Micout, P.; Mols, J. P.; Mouly, J. P.; Penichot, Y.; Rolquin, J.; Serfass, B.; Toussaint, J. C.; Usseglio, M.; Vasseur, G.; Yeche, C.; Zito, M.; Copty, N.; Purohit, M. V.; Yumiceva, F. X.; Adam, I.; Adesanya, A.; Anthony, P. L.; Aston, D.; Bartelt, J.; Becla, J.; Bell, R.; Bloom, E.; Boeheim, C. T.; Boyarski, A. M.; Boyce, R. F.; Briggs, D.; Bulos, F.; Burgess, W.; Byers, B.; Calderini, G.; Chestnut, R.; Claus, R.; Convery, M. R.; Coombes, R.; Cottrell, L.; Coupal, D. P.; Coward, D. H.; Craddock, W. W.; DeBarger, S.; DeStaebler, H.; Dorfan, J.; Doser, M.; Dunwoodie, W.; Dusatko, J. E.; Ecklund, S.; Fieguth, T. H.; Freytag, D. R.; Glanzman, T.; Godfrey, G. L.; Haller, G.; Hanushevsky, A.; Harris, J.; Hasan, A.; Hee, C.; Himel, T.; Huffer, M. E.; Hung, T.; Innes, W. R.; Jessop, C. P.; Kawahara, H.; Keller, L.; King, M. E.; Klaisner, L.; Krebs, H. J.; Langenegger, U.; Langeveld, W.; Leith, D. W. G. S.; Louie, S. K.; Luitz, S.; Luth, V.; Lynch, H. L.; McDonald, J.; Manzin, G.; Marsiske, H.; Mattison, T.; McCulloch, M.; McDougald, M.; McShurley, D.; Menke, S.; Messner, R.; Metcalfe, S.; Morii, M.; Mount, R.; Muller, D. R.; Nelson, D.; Nordby, M.; O'Grady, C. P.; Olavson, L.; Olsen, J.; O'Neill, F. G.; Oxoby, G.; Paolucci, P.; Pavel, T.; Perl, J.; Pertsova, M.; Petrak, S.; Putallaz, G.; Raines, P. E.; Ratcliff, B. N.; Reif, R.; Robertson, S. H.; Rochester, L. S.; Roodman, A.; Russel, J. J.; Sapozhnikov, L.; Saxton, O. H.; Schietinger, T.; Schindler, R. H.; Schwiening, J.; Sciolla, G.; Seeman, J. T.; Serbo, V. V.; Shapiro, S.; Skarpass, K., Sr.; Snyder, A.; Soderstrom, E.; Soha, A.; Spanier, S. M.; Stahl, A.; Stiles, P.; Su, D.; Sullivan, M. K.; Talby, M.; Tanaka, H. A.; Va'vra, J.; Wagner, S. R.; Wang, R.; Weber, T.; Weinstein, A. J. R.; White, J. L.; Wienands, U.; Wisniewski, W. J.; Young, C. C.; Yu, N.; Burchat, P. R.; Cheng, C. H.; Kirkby, D.; Meyer, T. I.; Roat, C.; Henderson, R.; Khan, N.; Berridge, S.; Bugg, W.; Cohn, H.; Hart, E.; Weidemann, A. W.; Benninger, T.; Izen, J. M.; Kitayama, I.; Lou, X. C.; Turcotte, M.; Bianchi, F.; Bona, M.; Daudo, F.; Di Girolamo, B.; Gamba, D.; Grosso, P.; Smol, A.; Trapani, P. P.; Zanin, D.; Bosisio, L.; Della Ricca, G.; Lanceri, L.; Pompili, A.; Poropat, P.; Prest, M.; Rashevskaia, I.; Vallazza, E.; Vuagnin, G.; Panvini, R. S.; Brown, C.; De Silva, A.; Kowalewski, R.; Pitman, D.; Roney, J. M.; Band, H. R.; Charles, E.; Dasu, S.; Elmer, P.; Johnson, J. R.; Nielsen, J.; Orejudos, W.; Pan, Y.; Prepost, R.; Scott, I. J.; Walsh, J.; Wu, S. L.; Yu, Z.; Zobernig, H.; Moore, T. B.; Neal, H.

    2002-02-01

    B AB AR, the detector for the SLAC PEP-II asymmetric e +e - B Factory operating at the ϒ(4 S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by d E/d x measurements in the tracking detectors and by a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

  12. Soft x-ray intensity profile measurements of electron cyclotron heated plasmas using semiconductor detector arrays in GAMMA 10 tandem mirror

    SciTech Connect

    Minami, R. Imai, T.; Kariya, T.; Numakura, T.; Eguchi, T.; Kawarasaki, R.; Nakazawa, K.; Kato, T.; Sato, F.; Nanzai, H.; Uehara, M.; Endo, Y.; Ichimura, M.

    2014-11-15

    Temporally and spatially resolved soft x-ray analyses of electron cyclotron heated plasmas are carried out by using semiconductor detector arrays in the GAMMA 10 tandem mirror. The detector array has 16-channel for the measurements of plasma x-ray profiles so as to make x-ray tomographic reconstructions. The characteristics of the detector array make it possible to obtain spatially resolved plasma electron temperatures down to a few tens eV and investigate various magnetohydrodynamic activities. High power electron cyclotron heating experiment for the central-cell region in GAMMA 10 has been started in order to reduce the electron drag by increasing the electron temperature.

  13. Soft x-ray intensity profile measurements of electron cyclotron heated plasmas using semiconductor detector arrays in GAMMA 10 tandem mirror

    NASA Astrophysics Data System (ADS)

    Minami, R.; Imai, T.; Kariya, T.; Numakura, T.; Eguchi, T.; Kawarasaki, R.; Nakazawa, K.; Kato, T.; Sato, F.; Nanzai, H.; Uehara, M.; Endo, Y.; Ichimura, M.

    2014-11-01

    Temporally and spatially resolved soft x-ray analyses of electron cyclotron heated plasmas are carried out by using semiconductor detector arrays in the GAMMA 10 tandem mirror. The detector array has 16-channel for the measurements of plasma x-ray profiles so as to make x-ray tomographic reconstructions. The characteristics of the detector array make it possible to obtain spatially resolved plasma electron temperatures down to a few tens eV and investigate various magnetohydrodynamic activities. High power electron cyclotron heating experiment for the central-cell region in GAMMA 10 has been started in order to reduce the electron drag by increasing the electron temperature.

  14. DALI2: A NaI(Tl) detector array for measurements of γ rays from fast nuclei

    NASA Astrophysics Data System (ADS)

    Takeuchi, S.; Motobayashi, T.; Togano, Y.; Matsushita, M.; Aoi, N.; Demichi, K.; Hasegawa, H.; Murakami, H.

    2014-11-01

    A NaI(Tl) detector array called DALI2 (Detector Array for Low Intensity radiation 2) has been constructed for in-beam γ-ray spectroscopy experiments with fast radioactive isotope (RI) beams. It consists typically of 186 NaI(Tl) scintillators covering polar angles from ~15° to ~160° with an average angular resolution of 6° in full width at half maximum. Its high granularity (good angular resolution) enables Doppler-shift corrections that result in, for example, 10% energy resolution and 20% full-energy photopeak efficiency for 1-MeV γ rays emitted from fast-moving nuclei (velocities of v / c ≃ 0.6). DALI2 has been employed successfully in numerous experiments using fast RI beams with velocities of v/c=0.3-0.6 provided by the RIKEN RI Beam Factory.

  15. Majo-ra-na: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements

    NASA Astrophysics Data System (ADS)

    Gehman, Victor

    2010-02-01

    The Majo-ra-na collaboration will search for neutrinoless double-beta decay (0νββ) by fielding an array of high-purity germanium (HPGe) detectors in ultra-clean electroformed-copper cryostats deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, present exciting new techniques for identifying and reducing backgrounds to the 0νββ signal. This should result in greatly improved sensitivity over previous generation experiments. The very low energy threshold attainable with PPC detectors also provides for a broader physics program including searches for dark matter and axions. The Majo-ra-na De-mon-strat-or is an R&D program that will field three ˜20 kg modules of PPC detectors at Sanford Underground Laboratory. Half of the detectors will be enriched to 86% in ^76Ge. Here, we will cover the motivation, design, recent progress and current status of this effort, with special attention to its physics reach. )

  16. Characterization of a novel two dimensional diode array the ''magic plate'' as a radiation detector for radiation therapy treatment

    SciTech Connect

    Wong, J. H. D.; Fuduli, I.; Carolan, M.; Petasecca, M.; Lerch, M. L. F.; Perevertaylo, V. L.; Metcalfe, P.; Rosenfeld, A. B.

    2012-05-15

    Purpose: Intensity modulated radiation therapy (IMRT) utilizes the technology of multileaf collimators to deliver highly modulated and complex radiation treatment. Dosimetric verification of the IMRT treatment requires the verification of the delivered dose distribution. Two dimensional ion chamber or diode arrays are gaining popularity as a dosimeter of choice due to their real time feedback compared to film dosimetry. This paper describes the characterization of a novel 2D diode array, which has been named the ''magic plate'' (MP). It was designed to function as a 2D transmission detector as well as a planar detector for dose distribution measurements in a solid water phantom for the dosimetric verification of IMRT treatment delivery. Methods: The prototype MP is an 11 x 11 detector array based on thin (50 {mu}m) epitaxial diode technology mounted on a 0.6 mm thick Kapton substrate using a proprietary ''drop-in'' technology developed by the Centre for Medical Radiation Physics, University of Wollongong. A full characterization of the detector was performed, including radiation damage study, dose per pulse effect, percent depth dose comparison with CC13 ion chamber and build up characteristics with a parallel plane ion chamber measurements, dose linearity, energy response and angular response. Results: Postirradiated magic plate diodes showed a reproducibility of 2.1%. The MP dose per pulse response decreased at higher dose rates while at lower dose rates the MP appears to be dose rate independent. The depth dose measurement of the MP agrees with ion chamber depth dose measurements to within 0.7% while dose linearity was excellent. MP showed angular response dependency due to the anisotropy of the silicon diode with the maximum variation in angular response of 10.8% at gantry angle 180 deg. Angular dependence was within 3.5% for the gantry angles {+-} 75 deg. The field size dependence of the MP at isocenter agrees with ion chamber measurement to within 1.1%. In

  17. Application of a single area array detector for acquistion, tracking and point-ahead in space optical communications

    NASA Technical Reports Server (NTRS)

    Clark, D. L.; Cosgrove, M.; Vanvranken, R.; Park, H.; Fitzmaurice, M.

    1989-01-01

    Functions of acquisition, tracking, and point-ahead in space optical communications are being combined into a single system utilizing an area array detector. An analysis is presented of the feasibility concept. The key parameters are: optical power less than 1 pW at 0.86 micrometer, acquisition in less than 30 seconds in an acquisition field of view (FOV) of 1 mrad, tracking with 0.5 microrad rms noise at 1000 Hz update rate, and point ahead transfer function precision of 0.25 microrad over a region of 150 microrad. Currently available array detectors were examined. The most demanding specifications are low output noise, a high detection efficiency, a large number of pixels, and frame rates over 1kHz. A proof of concept (POC) demonstration system is currently being built utilizing the Kodak HS-40 detector (a 128 x 128 photodiode array with a 64 channel CCD readout architecture which can be operated at frame rates as high as 40,000/sec). The POC system implements a windowing scheme and special purpose digital signal processing electronic for matched filter acquisition and tracking algorithms.

  18. SU-E-T-167: Characterization of In-House Plastic Scintillator Detectors Array for Radiation Therapy

    SciTech Connect

    Zhu, T; Liu, H; Dimofte, A; Darafsheh, A; Lin, H; Kassaee, A; Finlay, J; Both, S

    2015-06-15

    Purpose: To characterize basic performance of plastic scintillator detectors (PSD) array designed for dosimetry of radiation therapy. Methods: An in-house PSD array has been developed by placing single point PSD into customized 2D holder. Each point PSD is a plastic scintillating fiber-based detector designed for highly accurate measurement of small radiotherapy fields used in patient plan verification and machine commissioning and QA procedures. A parallel fiber without PSD is used for Cerenkov separation by subtracting from PSD readings. Cerenkov separation was confirmed by optical spectroscopy. Alternative Cerenkov separation approaches are also investigated. The optical signal was converted to electronic signal with a photodiode and then subsequently amplified. We measured its dosimetry performance, including percentage depth dose and output factor, and compared with reference ion chamber measurements. The PSD array is then placed along the radiation beam for multiple point dose measurement, representing subsets of PDD measurements, or perpendicular to the beam for profile measurements. Results: The dosimetry results of PSD point measurements agree well with reference ion chamber measurements. For percentage depth dose, the maximal differences between PSD and ion chamber results are 3.5% and 2.7% for 6MV and 15MV beams, respectively. For the output factors, PSD measurements are within 3% from ion chamber results. PDD and profile measurement with PSD array are also performed. Conclusions: The current design of multichannel PSD array is feasible for the dosimetry measurement in radiation therapy. Dose distribution along or perpendicular to the beam path could be measured. It might as well be used as range verification in proton therapy.A PS hollow fiber detector will be investigated to eliminate the Cerenkov radiation effect so that all 32 channels can be used.

  19. State of the art of AIM LWIR and VLWIR MCT 2D focal plane detector arrays for higher operating temperatures

    NASA Astrophysics Data System (ADS)

    Figgemeier, H.; Hanna, S.; Eich, D.; Mahlein, K.-M.; Fick, W.; Schirmacher, W.; Thöt, R.

    2016-05-01

    In this paper AIM presents its latest results on both n-on-p and p-on-n low dark current planar MCT photodiode technology LWIR and VLWIR two-dimensional focal plane detector arrays with a cut-off wavelength >11μm at 80K and a 640x512 pixel format at a 20μm pitch. Thermal dark currents significantly reduced as compared to `Tennant's Rule 07' at a yet good detection efficiency >60% as well as results from NETD and photo response performance characterization are presented. The demonstrated detector performance paces the way for a new generation of higher operating temperature LWIR MCT FPAs with a <30mK NETD up to a 110K detector operating temperature and with good operability.

  20. DETECTORS AND EXPERIMENTAL METHODS: Study of the characteristics of a scintillation array and single pixels for nuclear medicine imaging applications

    NASA Astrophysics Data System (ADS)

    Zhu, Jie; Ma, Hong-Guang; Ma, Wen-Yan; Zeng, Hui; Wang, Zhao-Min; Xu, Zi-Zong

    2009-04-01

    By using a pixelized Nal(Tl) crystal array coupled to a R2486 PSPMT, the characteristics of the array and of a single pixel, such as the light output, energy resolution, peak-to-valley ratio (P/V) and imaging performance of the detector were studied. The pixel size of the NaI(TI) scintillation pixel array is 2 mm×2 mm×5 mm. There are in total 484 pixels in a 22 × 22 matrix. In the pixel spectrum an average peak-to-valley ratio (P/V) of 16 was obtained. In the image of all the pixels, good values for the Peak-to-Valley ratios could be achieved, namely a mean of 17, a maximum of 45 and the average peak FWHM (the average value of intrinsic spatial resolution) of 2.3 mm. However, the PSPMT non-uniform response and the scintillation pixels array inhomogeneities degrade the imaging performance of the detector.

  1. The MINDView brain PET detector, feasibility study based on SiPM arrays

    NASA Astrophysics Data System (ADS)

    González, Antonio J.; Majewski, Stan; Sánchez, Filomeno; Aussenhofer, Sebastian; Aguilar, Albert; Conde, Pablo; Hernández, Liczandro; Vidal, Luis F.; Pani, Roberto; Bettiol, Marco; Fabbri, Andrea; Bert, Julien; Visvikis, Dimitris; Jackson, Carl; Murphy, John; O'Neill, Kevin; Benlloch, Jose M.

    2016-05-01

    The Multimodal Imaging of Neurological Disorders (MINDView) project aims to develop a dedicated brain Positron Emission Tomography (PET) scanner with sufficient resolution and sensitivity to visualize neurotransmitter pathways and their disruptions in mental disorders for diagnosis and follow-up treatment. The PET system should be compact and fully compatible with a Magnetic Resonance Imaging (MRI) device in order to allow its operation as a PET brain insert in a hybrid imaging setup with most MRI scanners. The proposed design will enable the currently-installed MRI base to be easily upgraded to PET/MRI systems. The current design for the PET insert consists of a 3-ring configuration with 20 modules per ring and an axial field of view of ~15 cm and a geometrical aperture of ~33 cm in diameter. When coupled to the new head Radio Frequency (RF) coil, the inner usable diameter of the complete PET-RF coil insert is reduced to 26 cm. Two scintillator configurations have been tested, namely a 3-layer staggered array of LYSO with 1.5 mm pixel size, with 35×35 elements (6 mm thickness each) and a black-painted monolithic LYSO block also covering about 50×50 mm2 active area with 20 mm thickness. Laboratory test results associated with the current MINDView PET module concept are presented in terms of key parameters' optimization, such as spatial and energy resolution, sensitivity and Depth of Interaction (DOI) capability. It was possible to resolve all pixel elements from the three scintillator layers with energy resolutions as good as 10%. The monolithic scintillator showed average detector resolutions varying from 3.5 mm in the entrance layer to better than 1.5 mm near the photosensor, with average energy resolutions of about 17%.

  2. A cryogenic testbed for the characterisation of large detector arrays for astronomical and Earth-observing applications in the near to very-long-wavelength infrared

    NASA Astrophysics Data System (ADS)

    Brien, Thomas L. R.; Ade, Peter A. R.; Haiml, Markus; Hargrave, Peter C.; Höhnemann, Holger; Pascale, Enzo; Sudiwala, Rashmi V.; Van Aken, Dirk

    2016-07-01

    In this paper we describe a cryogenic testbed designed to offer complete characterisation-via a minimal number of experimental configurations— of mercury cadmium telluride (MCT) detector arrays for low-photon background applications, including exoplanet science and solar system exploration. Specifically, the testbed offers a platform to measure the dark current of detector arrays at various temperatures, whilst also characterising their optical response in numerous spectral bands. The average modulation transfer function (MTF) can be found in both dimensions of the array along with the overall quantum efficiency. Working from a liquid-helium bath allows for measurement of arrays from 4.2 K and active-temperature control of the surface to which the array is mounted allows for characterisation of arrays at temperatures up to 80 K, with the temperature of the array holder known to an accuracy of at least 1 mK, with the same level of long-term stability.

  3. WE-AB-BRB-04: A Novel Monolithic Silicon 2D Detector Array for Use in Stereotactic Applications

    SciTech Connect

    Gargett, M; Petasecca, M; Alnaghy, S; Rosenfeld, A; Oborn, B; Metcalfe, P

    2015-06-15

    Purpose: To assess the capability of a novel 2D monolithic silicon detector array in measuring stereotactic photon fields. Methods: The silicon array detector used in this work, named Magic Plate-512 (MP512), is a thin monolithic silicon wafer (52 × 52 × 0.47 mm{sup 3}) with 512 ion-implanted diodes (0.5 × 0.5 mm{sup 2}). Adjacent pixels are spaced evenly with 2 mm pitch, covering a maximum detection area 46 mm wide. Its fast, FPGA based read-out system is synchronised with the linac to allow readout of all pixels pulse-by-pulse. A clinical SABR lung plan (consisting of 9 single segment beams, 6MV) was measured with the array at 1.5 cm depth in a solid water phantom (100 cm SSD). The typical field size was in the range of 3 × 3 cm{sup 2} to 4 × 4 cm{sup 2}. Each beam was delivered at perpendicular incidence to the detector plane so as to avoid the need for angular dependence corrections. The fields were measured under the same conditions using Gafchromic EBT3 film for comparison. The film was scanned at 72 dpi resolution, with the red channel data used for analysis. Results: Average gamma passing rates of (92.3 ± 1.8) % for 2%/2mm criteria, and (86.6 ± 2.3) % for 1%/2mm criteria were achieved for MP512, using EBT3 film as the reference distribution. The detector array was able to accurately measure the full-width-at-half-maximum (FWHM), to within (0.77 ± 0.01) mm accuracy when compared to film. The penumbral widths (80%-20%) were measured to within (0.30 ± 0.01) mm accuracy to film. Conclusion: The MP512 is a feasible option for measurement of stereotactic photon fields, with its high density of detection points making it useful for small field applications. The prototype array has demonstrated merit; in the future the development of a larger array detection area would be beneficial for clinical applications.

  4. Real-time 3D millimeter wave imaging based FMCW using GGD focal plane array as detectors

    NASA Astrophysics Data System (ADS)

    Levanon, Assaf; Rozban, Daniel; Kopeika, Natan S.; Yitzhaky, Yitzhak; Abramovich, Amir

    2014-03-01

    Millimeter wave (MMW) imaging systems are required for applications in medicine, communications, homeland security, and space technology. This is because there is no known ionization hazard for biological tissue, and atmospheric attenuation in this range of the spectrum is relatively low. The lack of inexpensive room temperature imaging systems makes it difficult to give a suitable MMW system for many of the above applications. 3D MMW imaging system based on chirp radar was studied previously using a scanning imaging system of a single detector. The system presented here proposes to employ a chirp radar method with a Glow Discharge Detector (GDD) Focal Plane Array (FPA) of plasma based detectors. Each point on the object corresponds to a point in the image and includes the distance information. This will enable 3D MMW imaging. The radar system requires that the millimeter wave detector (GDD) will be able to operate as a heterodyne detector. Since the source of radiation is a frequency modulated continuous wave (FMCW), the detected signal as a result of heterodyne detection gives the object's depth information according to value of difference frequency, in addition to the reflectance of the image. In this work we experimentally demonstrate the feasibility of implementing an imaging system based on radar principles and FPA of GDD devices. This imaging system is shown to be capable of imaging objects from distances of at least 10 meters.

  5. Final Scientific/Technical Report: Electronics for Large Superconducting Tunnel Junction Detector Arrays for Synchrotron Soft X-ray Research

    SciTech Connect

    Warburton, William K

    2009-03-06

    Superconducting tunnel junction (STJ) detectors offer a an approach to detecting soft x-rays with energy resolutions 4-5 times better and at rates 10 faster than traditions semiconductor detectors. To make such detectors feasible, however, then need to be deployed in large arrays of order 1000 detectors, which in turn implies that their processing electronics must be compact, fully computer controlled, and low cost per channel while still delivering ultra-low noise performance so as to not degrade the STJ's performance. We report on our progress in designing a compact, low cost preamplifier intended for this application. In particular, we were able to produce a prototype preamplifier of 2 sq-cm area and a parts cost of less than $30 that matched the energy resolution of the best conventional system to date and demonstrated its ability to acquire an STJ I-V curve under computer control, the critical step for determining and setting the detectors' operating points under software control.

  6. Si(Li)-NaI(Tl) sandwich detector array for measurements of trace radionuclides in soil samples

    SciTech Connect

    Strauss, M.G.; Sherman, I.S.; Roche, C.T.; Pehl, R.H.

    1985-01-01

    An ultra-sensitive x-/..gamma..-ray detector system for assaying trace radioactivity in actinide contaminated soil and ash samples has been developed. The new system consists of an array of 6 large Si(Li) x-ray detectors sensitive on both faces and mounted on edge in a paddle-shaped cryostat with a 14 cm dia Be window on each side. The paddle, with a sample of the soil placed at each window, is sandwiched between 2 large NaI(Tl) scintillators which suppress the ..gamma.. background. With x rays being measured simultaneously from soil in 2 sample holders and background reduced by 50% using anticoincidence, the sensitivity of this detector is 4 times higher than that of conventionally mounted Si(Li) detectors. A soil sample containing 50 pCi/g /sup 239/Pu was measured in 5 min with an uncertainty of <20% and a sample containing 7 pCi/g was measured in 1 hr. With FWHM resolution of 400 eV at 17 keV, the UL..beta../sub 1/ and NpL..beta../sub 1/ x-ray peaks are resolved thus permitting measurement of trace Pu in the presence of Am-241. This is the most sensitive and selective detector known for nondestructive assay of radioactivity in soil and other samples. 15 refs., 8 figs.

  7. Study of a new design of p-N semiconductor detector array for nuclear medicine imaging by monte carlo simulation codes.

    PubMed

    Hajizadeh-Safar, M; Ghorbani, M; Khoshkharam, S; Ashrafi, Z

    2014-07-01

    Gamma camera is an important apparatus in nuclear medicine imaging. Its detection part is consists of a scintillation detector with a heavy collimator. Substitution of semiconductor detectors instead of scintillator in these cameras has been effectively studied. In this study, it is aimed to introduce a new design of P-N semiconductor detector array for nuclear medicine imaging. A P-N semiconductor detector composed of N-SnO2 :F, and P-NiO:Li, has been introduced through simulating with MCNPX monte carlo codes. Its sensitivity with different factors such as thickness, dimension, and direction of emission photons were investigated. It is then used to configure a new design of an array in one-dimension and study its spatial resolution for nuclear medicine imaging. One-dimension array with 39 detectors was simulated to measure a predefined linear distribution of Tc(99_m) activity and its spatial resolution. The activity distribution was calculated from detector responses through mathematical linear optimization using LINPROG code on MATLAB software. Three different configurations of one-dimension detector array, horizontal, vertical one sided, and vertical double-sided were simulated. In all of these configurations, the energy windows of the photopeak were ± 1%. The results show that the detector response increases with an increase of dimension and thickness of the detector with the highest sensitivity for emission photons 15-30° above the surface. Horizontal configuration array of detectors is not suitable for imaging of line activity sources. The measured activity distribution with vertical configuration array, double-side detectors, has no similarity with emission sources and hence is not suitable for imaging purposes. Measured activity distribution using vertical configuration array, single side detectors has a good similarity with sources. Therefore, it could be introduced as a suitable configuration for nuclear medicine imaging. It has been shown that using

  8. Langley's CSI evolutionary model: Phase O

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith; Elliott, Kenny B.; Horta, Lucas G.; Bailey, Jim P.; Bruner, Anne M.; Sulla, Jeffrey L.; Won, John; Ugoletti, Roberto M.

    1991-01-01

    A testbed for the development of Controls Structures Interaction (CSI) technology to improve space science platform pointing is described. The evolutionary nature of the testbed will permit the study of global line-of-sight pointing in phases 0 and 1, whereas, multipayload pointing systems will be studied beginning with phase 2. The design, capabilities, and typical dynamic behavior of the phase 0 version of the CSI evolutionary model (CEM) is documented for investigator both internal and external to NASA. The model description includes line-of-sight pointing measurement, testbed structure, actuators, sensors, and real time computers, as well as finite element and state space models of major components.

  9. Development of the CSI phase-3 evolutionary model testbed

    NASA Technical Reports Server (NTRS)

    Gronet, M. J.; Davis, D. A.; Tan, M. K.

    1994-01-01

    This report documents the development effort for the reconfiguration of the Controls-Structures Integration (CSI) Evolutionary Model (CEM) Phase-2 testbed into the CEM Phase-3 configuration. This step responds to the need to develop and test CSI technologies associated with typical planned earth science and remote sensing platforms. The primary objective of the CEM Phase-3 ground testbed is to simulate the overall on-orbit dynamic behavior of the EOS AM-1 spacecraft. Key elements of the objective include approximating the low-frequency appendage dynamic interaction of EOS AM-1, allowing for the changeout of components, and simulating the free-free on-orbit environment using an advanced suspension system. The fundamentals of appendage dynamic interaction are reviewed. A new version of the multiple scaling method is used to design the testbed to have the full-scale geometry and dynamics of the EOS AM-1 spacecraft, but at one-tenth the weight. The testbed design is discussed, along with the testing of the solar array, high gain antenna, and strut components. Analytical performance comparisons show that the CEM Phase-3 testbed simulates the EOS AM-1 spacecraft with good fidelity for the important parameters of interest.

  10. SOLID2: an antibody array-based life-detector instrument in a Mars Drilling Simulation Experiment (MARTE).

    PubMed

    Parro, Víctor; Fernández-Calvo, Patricia; Rodríguez Manfredi, José A; Moreno-Paz, Mercedes; Rivas, Luis A; García-Villadangos, Miriam; Bonaccorsi, Rosalba; González-Pastor, José Eduardo; Prieto-Ballesteros, Olga; Schuerger, Andrew C; Davidson, Mark; Gómez-Elvira, Javier; Stoker, Carol R

    2008-10-01

    A field prototype of an antibody array-based life-detector instrument, Signs Of LIfe Detector (SOLID2), has been tested in a Mars drilling mission simulation called MARTE (Mars Astrobiology Research and Technology Experiment). As one of the analytical instruments on the MARTE robotic drilling rig, SOLID2 performed automatic sample processing and analysis of ground core samples (0.5 g) with protein microarrays that contained 157 different antibodies. Core samples from different depths (down to 5.5 m) were analyzed, and positive reactions were obtained in antibodies raised against the Gram-negative bacterium Leptospirillum ferrooxidans, a species of the genus Acidithiobacillus (both common microorganisms in the Río Tinto area), and extracts from biofilms and other natural samples from the Río Tinto area. These positive reactions were absent when the samples were previously subjected to a high-temperature treatment, which indicates the biological origin and structural dependency of the antibody-antigen reactions. We conclude that an antibody array-based life-detector instrument like SOLID2 can detect complex biological material, and it should be considered as a potential analytical instrument for future planetary missions that search for life.

  11. Anatomical Reconstruction and Functional Imaging Reveal an Ordered Array of Skylight Polarization Detectors in Drosophila

    PubMed Central

    Bleul, Christiane; Baumann-Klausener, Franziska; Labhart, Thomas; Dickinson, Michael H.

    2016-01-01

    Many insects exploit skylight polarization as a compass cue for orientation and navigation. In the fruit fly, Drosophila melanogaster, photoreceptors R7 and R8 in the dorsal rim area (DRA) of the compound eye are specialized to detect the electric vector (e-vector) of linearly polarized light. These photoreceptors are arranged in stacked pairs with identical fields of view and spectral sensitivities, but mutually orthogonal microvillar orientations. As in larger flies, we found that the microvillar orientation of the distal photoreceptor R7 changes in a fan-like fashion along the DRA. This anatomical arrangement suggests that the DRA constitutes a detector for skylight polarization, in which different e-vectors maximally excite different positions in the array. To test our hypothesis, we measured responses to polarized light of varying e-vector angles in the terminals of R7/8 cells using genetically encoded calcium indicators. Our data confirm a progression of preferred e-vector angles from anterior to posterior in the DRA, and a strict orthogonality between the e-vector preferences of paired R7/8 cells. We observed decreased activity in photoreceptors in response to flashes of light polarized orthogonally to their preferred e-vector angle, suggesting reciprocal inhibition between photoreceptors in the same medullar column, which may serve to increase polarization contrast. Together, our results indicate that the polarization-vision system relies on a spatial map of preferred e-vector angles at the earliest stage of sensory processing. SIGNIFICANCE STATEMENT The fly's visual system is an influential model system for studying neural computation, and much is known about its anatomy, physiology, and development. The circuits underlying motion processing have received the most attention, but researchers are increasingly investigating other functions, such as color perception and object recognition. In this work, we investigate the early neural processing of a somewhat

  12. A new detector array for diffractive physics in ALICE at the LHC

    SciTech Connect

    Corral, Gerardo Herrera

    2011-07-15

    We discuss some aspects of a new sub-detector for the ALICE experiment at the LHC. This detector would enhance the capabilities of ALICE to study several topics of diffractive as well as of photon induced physics. It consists of four stations of scintillator pads that would tag the diffractive gap more efficiently.

  13. CsI Calorimeter for a Compton-Pair Telescope

    NASA Astrophysics Data System (ADS)

    Grove, Eric J.

    We propose to build and test a hodoscopic CsI(Tl) scintillating-crystal calorimeter for a medium-energy γ-ray Compton and pair telescope. The design and technical approach for this calorimeter relies deeply on heritage from the Fermi LAT CsI Calorimeter, but it dramatically improves the low-energy performance of that design by reading out the scintillation light with silicon photomultipliers (SiPMs), making the technology developed for Fermi applicable in the Compton regime. While such a hodoscopic calorimeter is useful for an entire class of medium-energy γ-ray telescope designs, we propose to build it explicitly to support beam tests and balloon flight of the Proto-ComPair telescope, the development and construction of which was funded in a four-year APRA program beginning in 2015 ("ComPair: Steps to a Medium Energy γ-ray Mission" with PI J. McEnery of GSFC). That award did not include funding for its CsI calorimeter subsystem, and this proposal is intended to cover that gap. ComPair is a MIDEX-class instrument concept to perform a high-sensitivity survey of the γ-ray sky from 0.5 MeV to 500 MeV. ComPair is designed to provide a dramatic increase in sensitivity relative to previous instruments in this energy range (predominantly INTEGRAL/SPI and Compton COMPTEL), with the same transformative sensitivity increase – and corresponding scientific return– that the Fermi Large Area Telescope provided relative to Compton EGRET. To enable transformative science over a broad range of MeV energies and with a wide field of view, ComPair is a combined Compton telescope and pair telescope employing a silicon-strip tracker (for Compton scattering and pair conversion and tracking) and a solid-state CdZnTe calorimeter (for Compton absorption) and CsI calorimeter (for pair calorimetry), surrounded by a plastic scintillator anti-coincidence detector. Under the current proposal, we will complete the detailed design, assembly, and test of the CsI calorimeter for the risk

  14. Correction of complex nonlinear signal response from a pixel array detector

    DOE PAGES

    van Driel, Tim Brandt; Herrmann, Sven; Carini, Gabriella; ...

    2015-04-22

    The pulsed free-electron laser light sources represent a new challenge to photon area detectors due to the intrinsic spontaneous X-ray photon generation process that makes single-pulse detection necessary. Intensity fluctuations up to 100% between individual pulses lead to high linearity requirements in order to distinguish small signal changes. In real detectors, signal distortions as a function of the intensity distribution on the entire detector can occur. Here a robust method to correct this nonlinear response in an area detector is presented for the case of exposures to similar signals. The method is tested for the case of diffuse scattering frommore » liquids where relevant sub-1% signal changes appear on the same order as artifacts induced by the detector electronics.« less

  15. Correction of complex nonlinear signal response from a pixel array detector

    PubMed Central

    van Driel, Tim Brandt; Herrmann, Sven; Carini, Gabriella; Nielsen, Martin Meedom; Lemke, Henrik Till

    2015-01-01

    The pulsed free-electron laser light sources represent a new challenge to photon area detectors due to the intrinsic spontaneous X-ray photon generation process that makes single-pulse detection necessary. Intensity fluctuations up to 100% between individual pulses lead to high linearity requirements in order to distinguish small signal changes. In real detectors, signal distortions as a function of the intensity distribution on the entire detector can occur. Here a robust method to correct this nonlinear response in an area detector is presented for the case of exposures to similar signals. The method is tested for the case of diffuse scattering from liquids where relevant sub-1% signal changes appear on the same order as artifacts induced by the detector electronics. PMID:25931072

  16. Correction of complex nonlinear signal response from a pixel array detector

    SciTech Connect

    van Driel, Tim Brandt; Herrmann, Sven; Carini, Gabriella; Nielsen, Martin Meedom; Lemke, Henrik Till

    2015-04-22

    The pulsed free-electron laser light sources represent a new challenge to photon area detectors due to the intrinsic spontaneous X-ray photon generation process that makes single-pulse detection necessary. Intensity fluctuations up to 100% between individual pulses lead to high linearity requirements in order to distinguish small signal changes. In real detectors, signal distortions as a function of the intensity distribution on the entire detector can occur. Here a robust method to correct this nonlinear response in an area detector is presented for the case of exposures to similar signals. The method is tested for the case of diffuse scattering from liquids where relevant sub-1% signal changes appear on the same order as artifacts induced by the detector electronics.

  17. The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular mode

    NASA Astrophysics Data System (ADS)

    Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Myers, I.; Minamino, M.; Miyata, K.; Murano, Y.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2013-08-01

    We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array's middle drum detector and the direct comparison to the high resolution fly's eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.

  18. CSI: An Engaging Online Classroom Introduction Activity

    ERIC Educational Resources Information Center

    Stephens, Geralyn E.

    2015-01-01

    All course activities should be aimed at moving students towards the learning outcomes, including class introductions. This article provides detailed instructions for implementing an online Class Session Introductions (CSI) activity that immediately engages students with their peers, the content and the instructor. The activity may be useful to…

  19. Correction of dead-time and pile-up in a detector array for constant and rapidly varying counting rates

    NASA Astrophysics Data System (ADS)

    Guerrero, C.; Cano-Ott, D.; Mendoza, E.; Wright, T.

    2015-03-01

    The effect of dead-time and pile-up in counting experiments may become a significant source of uncertainty if not properly taken into account. Although analytical solutions to this problem have been proposed for simple set-ups with one or two detectors, these are limited when it comes to arrays where time correlation between the detector modules is used, and also in situations of variable counting rates. In this paper we describe the dead-time and pile-up corrections applied to the n_TOF Total Absorption Calorimeter (TAC), a 4π γ-ray detector made of 40 BaF2 modules operating at the CERN n_TOF facility. Our method is based on the simulation of the complete signal detection and event reconstruction processes and can be applied as well in the case of rapidly varying counting rates. The method is discussed in detail and then we present its successful application to the particular case of the measurement of 238U(n, γ) reactions with the TAC detector.

  20. Array of virtual Frisch-grid CZT detectors with common cathode readout and pulse-height correction

    SciTech Connect

    Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Egarievwe, E.U.; Fochuk, P.M.; Fuerstnau, M.; Gul, R.; Hossain, A.; Jones, F.; Kim, K.; Kopach, O.V.; Taggart, R.; Yang, G.; Ye, Z.; Xu, L.; and James, R.B.

    2010-08-01

    We present our new results from testing 15-mm-long virtual Frisch-grid CdZnTe detectors with a common-cathode readout for correcting pulse-height distortions. The array employs parallelepiped-shaped CdZnTe (CZT) detectors of a large geometrical aspect ratio, with two planar contacts on the top and bottom surfaces (anode and cathode) and an additional shielding electrode on the crystal's sides to create the virtual Frisch-grid effect. We optimized the geometry of the device and improved its spectral response. We found that reducing to 5 mm the length of the shielding electrode placed next to the anode had no adverse effects on the device's performance. At the same time, this allowed corrections for electron loss by reading the cathode signals to obtain depth information.

  1. Coherent 1-micron lidar measurements of atmospheric-turbulence-induced spatial decorrelation using a multielement heterodyne detector array

    NASA Technical Reports Server (NTRS)

    Chan, Kin P.; Killinger, Dennis K.

    1992-01-01

    A coherent 1-micron Nd:YAG lidar system is employed to measure directly the reduced spatial coherence length rho 0 of the lidar returns caused by atmospheric turbulence. The experiments were conducted by using a 2 x 2 heterodyne detector array, which permitted real-time spatial correlation measurements of the lidar returns at two different detector spacings. The spatial correlation coefficients and spatial coherence length of the lidar returns from a hard target were measured during a day-to-night time period when the atmospheric turbulence parameter, Cn-squared, was measured to vary from 2 x 10 exp -13 to 2 x 10 exp -4 m exp -2/3. These directly measured values of rho 0 as a function of Cn-squared were found to be in good agreement with theoretical predictions.

  2. Parallel optical coherence tomography in scattering samples using a two-dimensional smart-pixel detector array

    NASA Astrophysics Data System (ADS)

    Ducros, M.; Laubscher, M.; Karamata, B.; Bourquin, S.; Lasser, T.; Salathé, R. P.

    2002-02-01

    Parallel optical coherence tomography in scattering samples is demonstrated using a 58×58 smart-pixel detector array. A femtosecond mode-locked Ti:Sapphire laser in combination with a free space Michelson interferometer was employed to achieve 4 μm longitudinal resolution and 9 μm transverse resolution on a 260×260 μm2 field of view. We imaged a resolution target covered by an intralipid solution with different scattering coefficients as well as onion cells.

  3. Quantified, multi-scale X-ray fluorescence element mapping using the Maia detector array: application to mineral deposit studies

    NASA Astrophysics Data System (ADS)

    Fisher, Louise A.; Fougerouse, Denis; Cleverley, James S.; Ryan, Christopher G.; Micklethwaite, Steven; Halfpenny, Angela; Hough, Robert M.; Gee, Mary; Paterson, David; Howard, Daryl L.; Spiers, Kathryn

    2015-08-01

    The Maia large solid-angle detector array and imaging system is capable of collecting high-resolution images of up to ˜100 M pixels in size with dwell times of less than 0.2 ms per pixel and thus it is possible to document variation in textures associated with trace element chemistry by collecting quantified elemental maps of geological samples on the scale of entire thin sections in a short time frame (6-8 hr). The analysis is nondestructive and allows variation to be recognised on a centimetre scale while also recognising zonations at the micron scale.

  4. Short wave infrared InGaAs focal plane arrays detector: the performance optimization of photosensitive element

    NASA Astrophysics Data System (ADS)

    Gao, Xin-jiang; Tang, Zun-lie; Zhang, Xiu-chuan; Chen, Yang; Jiang, Li-qun; Cheng, Hong-bing

    2009-07-01

    Significant progress has been achieved in technology of the InGaAs focal plane arrays (FPA) detector operating in short wave infrared (SWIR) last two decades. The no cryogenic cooling, low manufacturing cost, low power, high sensitivity and maneuverability features inherent of InGaAs FPA make it as a mainstream SWIR FPA in a variety of critical military, national security, aerospace, telecommunications and industrial applications. These various types of passive image sensing or active illumination image detecting systems included range-gated imaging, 3-Dimensional Ladar, covert surveillance, pulsed laser beam profiling, machine vision, semiconductor inspection, free space optical communications beam tracker, hyperspectroscopy imaging and many others. In this paper the status and perspectives of hybrid InGaAs FPA which is composed of detector array (PDA) and CMOS readout integrate circuit (ROIC) are reviewed briefly. For various low light levels applications such as starlight or night sky illumination, we have made use of the interface circuit of capacitive feedback transimpedance amplifier (CTIA) in which the integration capacitor was adjustable, therefore implements of the physical and electrical characteristics matches between detector arrays and readout intergrate circuit was achieved excellently. Taking into account the influences of InGaAs detector arrays' optoelectronic characteristics on performance of the FPA, we discussed the key parameters of the photodiode in detailed, and the tradeoff between the responsivity, dark current, impedance at zero bias and junction capacitance of photosensitive element has been made to root out the impact factors. As a result of the educed approach of the photodiode's characteristics optimizing which involve with InGaAs PDA design and process, a high performance InGaAs FPA of 30um pixel pitch and 320×256 format has been developed of which the response spectrum range over 0.9um to 1.7um, the mean peak detectivity (λ=1.55

  5. Linear fitting of multi-threshold counting data with a pixel-array detector for spectral X-ray imaging

    PubMed Central

    Muir, Ryan D.; Pogranichney, Nicholas R.; Muir, J. Lewis; Sullivan, Shane Z.; Battaile, Kevin P.; Mulichak, Anne M.; Toth, Scott J.; Keefe, Lisa J.; Simpson, Garth J.

    2014-01-01

    Experiments and modeling are described to perform spectral fitting of multi-threshold counting measurements on a pixel-array detector. An analytical model was developed for describing the probability density function of detected voltage in X-ray photon-counting arrays, utilizing fractional photon counting to account for edge/corner effects from voltage plumes that spread across multiple pixels. Each pixel was mathematically calibrated by fitting the detected voltage distributions to the model at both 13.5 keV and 15.0 keV X-ray energies. The model and established pixel responses were then exploited to statistically recover images of X-ray intensity as a function of X-ray energy in a simulated multi-wavelength and multi-counting threshold experiment. PMID:25178010

  6. The energy spectrum of cosmic rays above 1017.2 eV measured by the fluorescence detectors of the Telescope Array experiment in seven years

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2016-07-01

    The Telescope Array (TA) experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The fluorescence detectors at two stations of TA are newly constructed and have now completed seven years of steady operation. One advantage of monocular analysis of the fluorescence detectors is a lower energy threshold for cosmic rays than that of other techniques like stereoscopic observations or coincidences with the surface detector array, allowing the measurement of an energy spectrum covering three orders of magnitude in energy. Analyzing data collected during those seven years, we report the energy spectrum of cosmic rays covering a broad range of energies above 1017.2eV measured by the fluorescence detectors and a comparison with previously published results.

  7. Development of a fast pixel array detector for use in microsecond time-resolved x-ray diffraction

    SciTech Connect

    Barna, S.L.; Gruner, S.M.; Shepherd, J.A.

    1995-08-01

    A large-area pixel x-ray detector is being developed to collect eight successive frames of wide dynamic range two-dimensional images at 200kHz rates. Such a detector, in conjunction with a synchrotron radiation x-ray source, will enable time-resolved x-ray studies of proteins and other materials on time scales which have previously been inaccessible. The detector will consist of an array of fully-depleted 150 micron square diodes connected to a CMOS integrated electronics layer with solder bump-bonding. During each framing period, the current resulting from the x-rays stopped in the diodes is integrated in the electronics layer, and then stored in one of eight storage capacitors underneath the pixel. After the last frame, the capacitors are read out at standard data transmission rates. The detector has been designed for a well-depth of at least 10,000 x-rays (at 20keV), and a noise level of one x-ray. Ultimately, the authors intend to construct a detector with over one million pixels (1024 by 1024). They present the results of their development effort and various features of the design. The electronics design is discussed, with special attention to the performance requirements. The choice and design of the detective diodes, as they relate to x-ray stopping power and charge collection, are presented. An analysis of various methods of bump bonding is also presented. Finally, the authors discuss the possible need for a radiation-blocking layer, to be placed between the electronics and the detective layer, and various methods they have pursued in the construction of such a layer.

  8. Parallel-vector computation for CSI-design code

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc T.

    1990-01-01

    Computational aspects of Control-Structure Interaction (CSI) DESIGN code is reviewed. Numerical intensive computation portions of CSI-DESIGN code were identified. Improvements in computational speed for the CSI-DESIGN code can be achieved by exploiting parallel and vector capabilities offered by modern computers, such as the Alliant, Convex, Cray-2, and Cray-YMP. Four options to generate the coefficient stiffness matrix and to solve the system of linear, simultaneous equations are currently available in the CSI-DESIGN code. A preprocessor to use RCM (Reverse Cuthill-Mackee) algorithm for bandwidth minimization was also developed for the CSI-DESIGN code. Preliminary results obtained by solving a small-scale, 97 node CSI finite element model (for eigensolution) have indicated that this new CSI-DESIGN code is 5 to 6 times faster (using 1 Alliant processor) than the old version of CSI-DESIGN code. This speed-up was achieved due to the RCM algorithm and the use of a new skyline solver. Efforts are underway to further improve the vector speed for CSI-DESIGN code, to evaluate its performance on a larger scale CSI model (such as phase zero CSI model) to make the code run efficiently on multiprocessor, parallel computer environment, and to make the code portable among different parallel computers available at NASA LaRC, such as Alliant, Convex, and Cray computers.

  9. RP-HPLC analysis of phenolic compounds and flavonoids in beverages and plant extracts using a CoulArray detector.

    PubMed

    Jandera, Pavel; Skeifíková, Veronika; Rehová, Lucie; Hájek, Tomás; Baldriánová, Lucie; Skopová, Gabriela; Kellner, Vladimír; Horna, Ales

    2005-06-01

    Methods were developed for the analysis of natural antioxidants including phenolic compounds and flavonoids in beverages and plant extracts using gradient HPLC with multi-channel electrochemical coulometric detection. Suitability of various reversed-phase columns for this purpose was compared; pH and mobile phase gradients were optimized with respect to the separation selectivity and sensitivity of detection. Because of different target compounds in various sample types, the overlapping resolution maps and the normalized resolution product approaches described earlier were used to select optimum columns and gradients to suit the analysis of the individual sample types. The methods were applied to the analysis of phenolic compounds and flavonoids in beer, wine, tea, and yacon extracts. 32 phenolic compounds were identified and determined, including derivatives of benzoic and cinnamic acids, flavones, and a few related glycosides. Eight-channel CoulArray detection offers high selectivity and sensitivity with limits of detection in the low microg L(-1) range, at least an order of magnitude lower than single-channel coulometric detection using the Coulochem detector. No special sample pretreatment is necessary and, because of the compatibility of the CoulArray detector with gradient elution, phenolic antioxidants of different polarities can be determined in a single run. In addition to the retention times, the ratios of the areas of the pre-dominant and post-dominant peaks to the area of the dominant peak can be used for improved identification of natural antioxidants.

  10. MCT-Based LWIR and VLWIR 2D Focal Plane Detector Arrays for Low Dark Current Applications at AIM

    NASA Astrophysics Data System (ADS)

    Hanna, S.; Eich, D.; Mahlein, K.-M.; Fick, W.; Schirmacher, W.; Thöt, R.; Wendler, J.; Figgemeier, H.

    2016-09-01

    We present our latest results on n-on- p as well as on p-on- n low dark current planar mercury cadmium telluride (MCT) photodiode technology long wavelength infrared (LWIR) and very long wavelength infrared (VLWIR) two-dimensional focal plane arrays (FPAs) with quantum efficiency (QE) cut-off wavelength >11 μm at 80 K and a 512 × 640 pixel format FPA at 20 μm pitch stitched from two 512 × 320 pixel photodiode arrays. Significantly reduced dark currents as compared with Tennant's "Rule 07" are demonstrated in both polarities while retaining good detection efficiency ≥60% for operating temperatures between 30 K and 100 K. This allows for the same dark current performance at 20 K higher operating temperature than with previous AIM INFRAROT-MODULE GmbH (AIM) technology. For p-on- n LWIR MCT FPAs, broadband photoresponse nonuniformity of only about 1.2% is achieved at 55 K with low defective pixel numbers. For an n-on- p VLWIR MCT FPA with 13.6 μm cut-off at 55 K, excellent photoresponse nonuniformity of about 3.1% is achieved at moderate defective pixel numbers. This advancement in detector technology paves the way for outstanding signal-to-noise ratio performance infrared detection, enabling cutting-edge next-generation LWIR/VLWIR detectors for space instruments and devices with higher operating temperature and low size, weight, and power for field applications.

  11. MT3250BA: a 320×256-50µm snapshot microbolometer ROIC for high-resistance detector arrays

    NASA Astrophysics Data System (ADS)

    Eminoglu, Selim; Akin, Tayfun

    2013-06-01

    This paper reports the development of a new microbolometer readout integrated circuit (MT3250BA) designed for high-resistance detector arrays. MT3250BA is the first microbolometer readout integrated circuit (ROIC) product from Mikro-Tasarim Ltd., which is a fabless IC design house specialized in the development of monolithic CMOS imaging sensors and ROICs for hybrid photonic imaging sensors and microbolometers. MT3250BA has a format of 320 × 256 and a pixel pitch of 50 µm, developed with a system-on-chip architecture in mind, where all the timing and biasing for this ROIC are generated on-chip without requiring any external inputs. MT3250BA is a highly configurable ROIC, where many of its features can be programmed through a 3-wire serial interface allowing on-the-fly configuration of many ROIC features. MT3250BA has 2 analog video outputs and 1 analog reference output for pseudo-differential operation, and the ROIC can be programmed to operate in the 1 or 2-output modes. A unique feature of MT3250BA is that it performs snapshot readout operation; therefore, the image quality will only be limited by the thermal time constant of the detector pixels, but not by the scanning speed of the ROIC, as commonly found in the conventional microbolometer ROICs performing line-by-line (rolling-line) readout operation. The signal integration is performed at the pixel level in parallel for the whole array, and signal integration time can be programmed from 0.1 µs up to 100 ms in steps of 0.1 µs. The ROIC is designed to work with high-resistance detector arrays with pixel resistance values higher than 250 kΩ. The detector bias voltage can be programmed on-chip over a 2 V range with a resolution of 1 mV. The ROIC has a measured input referred noise of 260 µV rms at 300 K. The ROIC can be used to build a microbolometer infrared sensor with an NETD value below 100 mK using a microbolometer detector array fabrication technology with a high detector resistance value (≥ 250 K

  12. Time walk correction for TOF-PET detectors based on a monolithic scintillation crystal coupled to a photosensor array

    NASA Astrophysics Data System (ADS)

    Vinke, R.; Löhner, H.; Schaart, D. R.; van Dam, H. T.; Seifert, S.; Beekman, F. J.; Dendooven, P.

    2010-09-01

    When optimizing the timing performance of a time-of-flight positron emission tomography (TOF-PET) detector based on a monolithic scintillation crystal coupled to a photosensor array, time walk as a function of annihilation photon interaction location inside the crystal needs to be considered. In order to determine the 3D spatial coordinates of the annihilation photon interaction location, a maximum likelihood estimation algorithm was developed, based on a detector characterization by a scan of a 511 keV photon beam across the front and one of the side surfaces of the crystal. The time walk effect was investigated using a 20 mm×20 mm×12 mm LYSO crystal coupled to a fast 4×4 multi-anode photomultiplier tube (MAPMT). In the plane parallel to the photosensor array, a spatial resolution of 2.4 mm FWHM is obtained. In the direction perpendicular to the MAPMT (depth-of-interaction, DOI), the resolution ranges from 2.3 mm FWHM near the MAPMT to 4 mm FWHM at a distance of 10 mm. These resolutions are uncorrected for the ˜1 mm beam diameter. A coincidence timing resolution of 358 ps FWHM is obtained in coincidence with a BaF 2 detector. A time walk depending on the 3D annihilation photon interaction location is observed. Throughout the crystal, the time walk spans a range of 100 ps. Calibration of the time walk vs. interaction location allows an event-by-event correction of the time walk.

  13. Characterization of a Prototype TES-Based Anti-coincidence Detector for Use with Future X-ray Calorimeter Arrays

    NASA Astrophysics Data System (ADS)

    Busch, S. E.; Yoon, W. S.; Adams, J. S.; Bailey, C. N.; Bandler, S. R.; Chervenak, J. A.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Lee, S.-J.; Porst, J.-P.; Porter, F. S.; Sadleir, J. E.; Smith, S. J.; Sultana, M.

    2016-07-01

    For future X-ray observatories utilizing transition-edge sensor (TES) microcalorimeters, an anti-coincidence detector (anti-co) is required to discriminate X-ray (˜ 0.1-10 keV) signals from non-X-ray background events, such as ionizing particles. We have developed a prototype anti-co that utilizes TESs, which will be compatible with the TES focal-plane arrays planned for future X-ray observatories. This anti-co is based upon the cryogenic dark matter search II detector design. It is a silicon wafer covered with superconducting collection fins and TES microcalorimeters. Minimum ionizing particles deposit energy while passing through the silicon. The athermal phonons produced by these events are absorbed in the superconducting fins, breaking Cooper pairs. The resulting quasiparticles diffuse along the superconducting fin, producing a signal when they reach the TES. By determining a correlation between detections in the anti-co and the X-ray detector one can identify and flag these background events. We have fabricated and tested a single-channel prototype anti-co device on a 1.5 × 1.9 cm^2 chip. We have measured the signals in this device from photons of several energies between 1.5 and 60 keV, as well as laboratory background events, demonstrating a threshold ˜ 100 times lower than is needed to detect minimum ionizing particles.

  14. (55)Fe X-ray Response of HgCdTe NIR Detector Arrays

    NASA Technical Reports Server (NTRS)

    Fox, Ori; Rauscher, Bernard J.

    2008-01-01

    Conversion gain is a fundamental parameter in detector characteristics that is used to measure many identifying detector properties, including read noise, dark current, and quantum efficiency (QE). Charge coupling effects, such as inter-pixel capacitance, attenuate photon shot noise and result in an overestimation of of conversion gain when implementing the photon transfer technique. The (55)Fe X-ray technique is a direct and simple method by which to measure the conversion gain by comparing the observed instrumental counts (ADU) to the known charge (e-) liberated by a single X-ray photon. Here we present the calibrated pair production energy for 1.7 micron HgCdTe infrared detectors.

  15. Array-compatible transition-edge sensor microcalorimeter {gamma}-ray detector with 42 eV energy resolution at 103 keV

    SciTech Connect

    Zink, B. L.; Ullom, J. N.; Beall, J. A.; Irwin, K. D.; Doriese, W. B.; Duncan, W. D.; Ferreira, L.; Hilton, G. C.; Horansky, R. D.; Reintsema, C. D.; Vale, L. R.

    2006-09-18

    The authors describe a microcalorimeter {gamma}-ray detector with measured energy resolution of 42 eV full width at half maximum for 103 keV photons. This detector consists of a thermally isolated superconducting transition-edge thermometer and a superconducting bulk tin photon absorber. The absorber is attached with a technique compatible with producing arrays of high-resolution {gamma}-ray detectors. The results of a detailed characterization of the detector, which includes measurements of the complex impedance, detector noise, and time-domain pulse response, suggest that a deeper understanding and optimization of the thermal transport between the absorber and thermometer could significantly improve the energy resolution of future detectors.

  16. High-gain and low-excess noise near-infrared single-photon avalanche detector arrays

    NASA Astrophysics Data System (ADS)

    Linga, Krishna; Yevtukhov, Yuriy; Liang, Bing

    2010-04-01

    We have designed and developed a new family of photodetectors and arrays with Internal Discrete Amplification (IDA) mechanism for the realization of very high gain and low excess noise factor in the visible and near infrared spectral regions. These devices surpass many limitations of the Single Photon Avalanche Photodetectors such as ultra low excess noise factor, very high gain, lower reset time (< 200 ns). These devices are very simple to operate in the non-gated mode under a constant dc bias voltage. Because of its unique characteristics of self-quenching and self-recovery, no external quenching circuit is needed. This unique feature of self quenching and self-recovery makes it simple to less complex readout integrated circuit to realize large format detector arrays. In this paper, we present the discrete amplification design approach used for the development of self reset, high gain photodetector arrays in the near infrared wavelength region. The demonstrated device performance far exceeds any available solid state Photodetectors in the near infrared wavelength range. These devices are ideal for researchers in the field of spectroscopy, industrial and scientific instrumentation, Ladar, quantum cryptography, night vision and other military, defense and aerospace applications.

  17. Low dark current MCT-based focal plane detector arrays for the LWIR and VLWIR developed at AIM

    NASA Astrophysics Data System (ADS)

    Gassmann, Kai Uwe; Eich, Detlef; Fick, Wolfgang; Figgemeier, Heinrich; Hanna, Stefan; Thöt, Richard

    2015-10-01

    For nearly 40 years AIM develops, manufactures and delivers photo-voltaic and photo-conductive infrared sensors and associated cryogenic coolers which are mainly used for military applications like pilotage, weapon sights, UAVs or vehicle platforms. In 2005 AIM started to provide the competences also for space applications like IR detector units for the SLSTR instrument on board of the Sentinel 3 satellite, the hyperspectral SWIR Imager for EnMAP or pushbroom detectors for high resolution Earth observation satellites. Meanwhile AIM delivered more than 25 Flight Models for several customers. The first European pulse-tube cooler ever operating on-board of a satellite is made by AIM. AIM homes the required infrared core capabilities such as design and manufacturing of focal plane assemblies, detector housing technologies, development and manufacturing of cryocoolers and also data processing for thermal IR cameras under one roof which enables high flexibility to react to customer needs and assures economical solutions. Cryogenically cooled Hg(1-x)CdxTe (MCT) quantum detectors are unequalled for applications requiring high imaging as well as high radiometric performance in the infrared spectral range. Compared with other technologies, they provide several advantages, such as the highest quantum efficiency, lower power dissipation compared to photoconductive devices and fast response times, hence outperforming micro-bolometer arrays. However, achieving an excellent MCT detector performance at long (LWIR) and very long (VLWIR) infrared wavelengths is challenging due to the exponential increase in the thermally generated photodiode dark current with increasing cut-off wavelength and / or operating temperature. Dark current is a critical design driver, especially for LWIR / VLWIR multi-spectral imagers with moderate signal levels or hyper-spectral Fourier spectrometers operating deep into the VLWIR spectral region. Consequently, low dark current (LDC) technologies are the

  18. Operation of an array of field-change detectors to provide ground truth for FORTE data

    SciTech Connect

    Massey, R.S.; Eack, K.B.; Eberle, M.H.; Shao, X.M.; Smith, D.A.; Wiens, K.C.

    1999-06-01

    The authors have deployed an array of fast electric-field-change sensors around the state of New Mexico to help identify the lightning processes responsible for the VHF RF signals detected by the FORTE satellite`s wide-band transient radio emission receivers. The array provides them with locations and electric-field waveforms for events within New Mexico and into surrounding states, and operates continuously. They are particularly interested in events for which there are coincident FORTE observations. For these events, they can correct both the array and FORTE waveforms for time of flight, and can plot the two waveforms on a common time axis. Most of the coincident events are from cloud-go-ground discharges, but the most powerful are from a little-studied class of events variously called narrow bipolar events and compact intra-cloud discharges. They have therefore focused their attention on these events whether or not FORTE was in position to observe them.

  19. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters)

    PubMed Central

    Sisniega, A; Zbijewski, W; Stayman, J W; Xu, J; Taguchi, K; Fredenberg, E; Lundqvist, Mats; Siewerdsen, J H

    2016-01-01

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm × 25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40% reduction in the

  20. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters)

    NASA Astrophysics Data System (ADS)

    Sisniega, A.; Zbijewski, W.; Stayman, J. W.; Xu, J.; Taguchi, K.; Fredenberg, E.; Lundqvist, Mats; Siewerdsen, J. H.

    2016-01-01

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

  1. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters).

    PubMed

    Sisniega, A; Zbijewski, W; Stayman, J W; Xu, J; Taguchi, K; Fredenberg, E; Lundqvist, Mats; Siewerdsen, J H

    2016-01-07

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

  2. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    NASA Astrophysics Data System (ADS)

    Leem, Hyun Tae; Choi, Yong; Kim, Kyu Bom; Lee, Sangwon; Yamamoto, Seiichi; Yeom, Jung-Yeol

    2017-02-01

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO4 reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm2 and the size of each LGSO scintillator element was 0.7×0.7×6 mm3. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400-600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  3. Low SWaP MWIR detector based on XBn focal plane array

    NASA Astrophysics Data System (ADS)

    Klipstein, P. C.; Gross, Y.; Aronov, D.; ben Ezra, M.; Berkowicz, E.; Cohen, Y.; Fraenkel, R.; Glozman, A.; Grossman, S.; Klin, O.; Lukomsky, I.; Marlowitz, T.; Shkedy, L.; Shtrichman, I.; Snapi, N.; Tuito, A.; Yassen, M.; Weiss, E.

    2013-06-01

    Over the past few years, a new type of High Operating Temperature (HOT) photon detector has been developed at SCD, which operates in the blue part of the MWIR window of the atmosphere (3.4-4.2 μm). This window is generally more transparent than the red part of the MWIR window (4.4-4.9 μm), especially for mid and long range applications. The detector has an InAsSb active layer, and is based on the new "XBn" device concept. We have analyzed various electrooptical systems at different atmospheric temperatures, based on XBn-InAsSb operating at 150K and epi-InSb at 95K, respectively, and find that the typical recognition ranges of both detector technologies are similar. Therefore, for very many applications there is no disadvantage to using XBn-InAsSb instead of InSb. On the other hand XBn technology confers many advantages, particularly in low Size, Weight and Power (SWaP) and in the high reliability of the cooler and Integrated Detector Cooler Assembly (IDCA). In this work we present a new IDCA, designed for 150K operation. The 15 μm pitch 640×512 digital FPA is housed in a robust, light-weight, miniaturised Dewar, attached to Ricor's K562S Stirling cycle cooler. The complete IDCA has a diameter of 28 mm, length of 80 mm and weight of < 300 gm. The total IDCA power consumption is ~ 3W at a 60Hz frame rate, including an external miniature proximity card attached to the outside of the Dewar. We describe some of the key performance parameters of the new detector, including its NETD, RNU and operability, pixel cross-talk, and early stage yield results from our production line.

  4. A Photoactivated Gas Detector for Toluene Sensing at Room Temperature Based on New Coral-Like ZnO Nanostructure Arrays.

    PubMed

    Yeh, Li-Ko; Luo, Jie-Chun; Chen, Min-Chun; Wu, Chih-Hung; Chen, Jian-Zhang; Cheng, I-Chun; Hsu, Cheng-Che; Tian, Wei-Cheng

    2016-10-31

    A photoactivated gas detector operated at room temperature was microfabricated using a simple hydrothermal method. We report that the photoactivated gas detector can detect toluene using a UV illumination of 2 μW/cm². By ultraviolet (UV) illumination, gas detectors sense toluene at room temperature without heating. A significant enhancement of detector sensitivity is achieved because of the high surface-area-to-volume ratio of the morphology of the coral-like ZnO nanorods arrays (NRAs) and the increased number of photo-induced oxygen ions under UV illumination. The corresponding sensitivity (ΔR/R₀) of the detector based on coral-like ZnO NRAs is enhanced by approximately 1022% compared to that of thin-film detectors. The proposed detector greatly extends the dynamic range of detection of metal-oxide-based detectors for gas sensing applications. We report the first-ever detection of toluene with a novel coral-like NRAs gas detector at room temperature. A sensing mechanism model is also proposed to explain the sensing responses of gas detectors based on coral-like ZnO NRAs.

  5. A Photoactivated Gas Detector for Toluene Sensing at Room Temperature Based on New Coral-Like ZnO Nanostructure Arrays

    PubMed Central

    Yeh, Li-Ko; Luo, Jie-Chun; Chen, Min-Chun; Wu, Chih-Hung; Chen, Jian-Zhang; Cheng, I-Chun; Hsu, Cheng-Che; Tian, Wei-Cheng

    2016-01-01

    A photoactivated gas detector operated at room temperature was microfabricated using a simple hydrothermal method. We report that the photoactivated gas detector can detect toluene using a UV illumination of 2 μW/cm2. By ultraviolet (UV) illumination, gas detectors sense toluene at room temperature without heating. A significant enhancement of detector sensitivity is achieved because of the high surface-area-to-volume ratio of the morphology of the coral-like ZnO nanorods arrays (NRAs) and the increased number of photo-induced oxygen ions under UV illumination. The corresponding sensitivity (ΔR/R0) of the detector based on coral-like ZnO NRAs is enhanced by approximately 1022% compared to that of thin-film detectors. The proposed detector greatly extends the dynamic range of detection of metal-oxide-based detectors for gas sensing applications. We report the first-ever detection of toluene with a novel coral-like NRAs gas detector at room temperature. A sensing mechanism model is also proposed to explain the sensing responses of gas detectors based on coral-like ZnO NRAs. PMID:27809222

  6. Instrumentation: Photodiode Array Detectors in UV-VIS Spectroscopy. Part II.

    ERIC Educational Resources Information Center

    Jones, Dianna G.

    1985-01-01

    A previous part (Analytical Chemistry; v57 n9 p1057A) discussed the theoretical aspects of diode ultraviolet-visual (UV-VIS) spectroscopy. This part describes the applications of diode arrays in analytical chemistry, also considering spectroelectrochemistry, high performance liquid chromatography (HPLC), HPLC data processing, stopped flow, and…

  7. 320 x 256 Complementary Barrier Infrared Detector Focal Plane Array for Long-Wave Infrared Imaging

    NASA Technical Reports Server (NTRS)

    Nguyen, Jean; Rafol, Sir B.; Soibel, Alexander; Khoskhlagh, Arezou; Ting, David Z.-Y.; Liu, John K.; Mumolo, Jason M.; Gunapala, Sarath D.

    2012-01-01

    A 320 x 256 Complementary Barrier Infrared (CBIRD) focal plane array for long-wavelength infrared (LWIR) imaging is reported. The arrays were grown by molecular beam expitaxy (MBE) with a 300 period 1.9 um thick absorber. The mean dark current density of 2.2 x 10-4 A/cm2 was measured at an operating bias of 128 mV with a long wavelength cutoff of 8.8 ?m observed at 50% of the peak. The maximum quantum efficiency was 54% measured at 5.6 ?m. Operating at T = 80K, the array yielded an 81% fill factor with 97% operability. Good imagery with a mean noise equivalent different temperature (NE?T) of 18.6 mK and a mean detectivity of D* = 1.3 x 1011 cm-Hz1/2/W was achieved. The substrate was thinned using mechanical lapping and neither an AR coating nor a passivation layer was applied. This article provides the details of the fabrication process for achieving low-dark current LWIR CBIRD arrays. Discussion for an effective hard mask for excellent pattern transfer is given and appropriate mounting techniques for good thermal contact during the dry etching process is described. The challenges and differences between etching large 200 ?m test diodes and small 28 ?m FPA pixels are given.

  8. HgCdTe e-APD detector arrays with single photon sensitivity for space lidar applications

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoli; Abshire, James B.; Beck, Jeffrey D.

    2014-05-01

    A multi-element HgCdTe electron initiated avalanche photodiode (e-APD) array has been developed for space lidar. The detector array was fabricated with 4.3μm cutoff HgCdTe with a spectral response from 0.4 to 4.3 μm. We have demonstrated a 4x4 e-APD array with 80 μm square elements followed by a custom cryogenic CMOS read-out integrated circuit (ROIC). The device operates at 77K inside a small closed-cycle cooler-Dewar with the support electronics integrated in a field programmable gate array. Measurements showed a unity gain quantum efficiency of about 90% at 1.5-1.6 μm wavelength. The bulk dark current of the HgCdTe e-APD at 77K was less than 50,000 input referred electrons/s at 12 V APD bias where the APD gain was 620 and the measured noise equivalent power (NEP) was 0.4 fW/Hz1/2. The electrical bandwidth of the device was about 6 MHz, mostly limited by the ROIC, but sufficient for the lidar application. Although the devices were designed for low bandwidth pulse detections, the high gain and low dark current enabled them to be used for single photon detections. Because the APD was biased below the break-down voltage, the output is linear to the input signal and there were no nonlinear effect such as dead-time and afterpulsing, and no need for gated operation. A new series of HgCdTe e-APDs have also been developed with a much wider bandwidth ROIC and higher APD gain, which is expected to give a much better performance in single photon detections.

  9. Reconstruction accuracy of the surface detector array of the Pierre Auger Observatory

    SciTech Connect

    Ave, M.

    2007-09-01

    The reconstruction of extensive air showers (arrival direction, core position and energy estimation) by the surface detector of the Pierre Auger Observatory is discussed together with the corresponding accuracy. We determine the angular reconstruction accuracy as a function of the station multiplicity by using two different approaches. We discuss statistical and systematic uncertainties in the determination of the signal at 1000 m from the core, S(1000), which is used to estimate the primary energy.

  10. Room temperature detector array technology for the terahertz to far-infrared.

    SciTech Connect

    Camacho, Ryan; Shaw, Michael; Zhang, X.; Tao, Hu; Lentine, Anthony L.; Wright, Jeremy Benjamin; Shaner, Eric Arthur; Trotter, Douglas Chandler; Averitt, Richard D.; Kadlec, Emil G; Rakich, Peter T.

    2011-10-01

    Thermal detection has made extensive progress in the last 40 years, however, the speed and detectivity can still be improved. The advancement of silicon photonic microring resonators has made them intriguing for detection devices due to their small size and high quality factors. Implementing silicon photonic microring or microdisk resonators as a means of a thermal detector gives rise to higher speed and detectivity, as well as lower noise compared to conventional devices with electrical readouts. This LDRD effort explored the design and measurements of silicon photonic microdisk resonators used for thermal detection. The characteristic values, consisting of the thermal time constant ({tau} {approx} 2 ms) and noise equivalent power were measured and found to surpass the performance of the best microbolometers. Furthermore the detectivity was found to be D{sub {lambda}} = 2.47 x 10{sup 8} cm {center_dot} {radical}Hz/W at 10.6 {mu}m which is comparable to commercial detectors. Subsequent design modifications should increase the detectivity by another order of magnitude. Thermal detection in the terahertz (THz) remains underdeveloped, opening a door for new innovative technologies such as metamaterial enhanced detectors. This project also explored the use of metamaterials in conjunction with a cantilever design for detection in the THz region and demonstrated the use of metamaterials as custom thin film absorbers for thermal detection. While much work remains to integrate these technologies into a unified platform, the early stages of research show promising futures for use in thermal detection.

  11. A pure CsI calorimeter for the Belle II experiment at SuperKEKB

    NASA Astrophysics Data System (ADS)

    Aloisio, A.; Baccaro, S.; Bernieri, E.; Branchini, P.; Budano, A.; Budano, F.; Cecchi, C.; Cemmi, A.; Corradi, G.; De Lucia, E.; De Nardo, G.; de Sangro, R.; Finocchiaro, G.; Fiore, S.; Giordano, R.; Manoni, E.; Merola, M.; Montecchi, M.; Oberhof, B.; Passeri, A.; Peruzzi, I.; Piccolo, M.; Rossi, A.; Sciacca, C.; Tagnani, D.

    2016-07-01

    The new SuperKEKB collider will be an upgrade of the existing KEKB electron-positron asymmetric collider, with a target luminosity of 8 ×1035cm-2s-1, about 40 times greater than the previous one. The accelerator upgrade is based on the novel low-emittance "nanobeams" scheme. The detector will also be upgraded to cope with the higher luminosity, pile-up and occupancy. We report on the development of the new pure CsI calorimeter for the forward region. An intensive R&D has been carried out to study the performance of pure CsI crystals with Avalanche Photodiodes readout. Results on the signal to noise ratio for different sensors and front end electronics configurations will be presented. A matrix of 16 crystals has been tested with the electron beam at the BTF facility in Frascati. Results in terms of energy resolution of this prototype will also be discussed.

  12. Fingerprint analysis and simultaneous determination of phenolic compounds in extracts of Curculiginis Rhizoma by HPLC-diode array detector.

    PubMed

    Bian, Qingya; Yang, Hui; Chan, Chi-On; Jin, Dengping; Mok, Daniel Kam-Wah; Chen, Sibao

    2013-01-01

    Curculiginis Rhizoma (Curculigo orchioides GAERTN.) is a well-known Chinese herbal medicine, as well as an important Rasayana drug in India. Current criteria of quality control on this herb are to quantitatively analyze single compound curculigoside, which fail to comprehensively evaluate quality of this herb. In this paper, a simple and reliable HPLC coupled with diode array detector (DAD) method was developed to evaluate the quality of Curculiginis Rhizoma through establishing chromatographic fingerprint and simultaneously quantitating four phenolic compounds, orcinol glucoside, orcinol, 2,6-dimethoxybenzoic acid and curculigoside. The fingerprint displayed eleven common peaks, and the similarity index of different samples was in a range of 0.890-0.977. Validation of the method was acceptable, with 96.03-102.82% accuracy in recovery test and inter and intra-day precisions were less than 2%. This developed method by having a combination of chromatographic fingerprint and quantitation analysis could be applied to the quality control of Curculiginis Rhizoma.

  13. Spectral Resolution for Five-Element, Filtered, X-Ray Detector (XRD) Arrays Using the Methods of Backus and Gilbert

    SciTech Connect

    FEHL,DAVID LEE; BIGGS,F.; CHANDLER,GORDON A.; STYGAR,WILLIAM A.

    2000-01-17

    The generalized method of Backus and Gilbert (BG) is described and applied to the inverse problem of obtaining spectra from a 5-channel, filtered array of x-ray detectors (XRD's). This diagnostic is routinely fielded on the Z facility at Sandia National Laboratories to study soft x-ray photons ({le}2300 eV), emitted by high density Z-pinch plasmas. The BG method defines spectral resolution limits on the system of response functions that are in good agreement with the unfold method currently in use. The resolution so defined is independent of the source spectrum. For noise-free, simulated data the BG approximating function is also in reasonable agreement with the source spectrum (150 eV black-body) and the unfold. This function may be used as an initial trial function for iterative methods or a regularization model.

  14. A low power X-ray diffractometer for soil analysis in remote locations employing a multiwire proportional counter detector array.

    NASA Technical Reports Server (NTRS)

    Gregory, J. C.; Parnell, T. A.

    1972-01-01

    A low power X-ray powder diffraction system suitable for remote mineralogical analysis of lunar, planetary, or asteroid soils has been designed. A one Curie Fe-55 source provides a monochromatic X-ray beam of 5.9 keV. Seeman-Bohlin focusing geometry is employed in the camera, allowing peak detection to proceed simultaneously at all angles and obviating the need for moving parts. The detector system is an array of 500-600 proportional counters with a wire-spacing of 1 mm. An electronics unit comprising preamplifier, postamplifier, window discriminators, and storage flip-flops requiring only 3.5 milliwatts has been designed and tested. Total instrument power is less than 5 W.

  15. A 128 x 128 InGaAs detector array for 1.0 - 1.7 microns

    NASA Technical Reports Server (NTRS)

    Olsen, G.; Joshi, A.; Lange, M.; Woodruff, K.; Mykietyn, E.; Gay, D.; Ackley, D.; Erickson, G.; Ban, V.; Staller, C.

    1990-01-01

    A two-dimensional 128 x 128 detector array for the 1.0 - 1.7 micron spectral region has been demonstrated with indium gallium arsenide. The 30 micron square pixels had 60 micron spacing in both directions and were designed to be compatible with a 2D Reticon multiplexer. Dark currents below 100 pA, capacitance near 0.1 pF, and quantum efficiencies above 80 percent were measured. Probe maps of dark current and quantum efficiency are presented along with pixel dropout data and wafer yield which was as high as 99.89 percent (7 dropouts) in an area of 6528 pixels and 99.37 percent (103 dropouts) over an entire 128 x 128 pixel region.

  16. 1K X 1K Si:As IBC detector arrays for JWST MIRI and other applications

    NASA Astrophysics Data System (ADS)

    Love, Peter J.; Hoffman, Alan W.; Lum, Nancy A.; Ando, Ken J.; Ritchie, William D.; Therrien, Neil J.; Toth, Andrew G.; Holcombe, Roger S.

    2004-09-01

    1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by Raytheon Vision Systems (RVS) for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). The devices are also suitable for other low-background applications. The Si:As IBC detectors respond out to ~28 microns, covering an important mid-IR region beyond the 1-5 micron range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. A mid-infrared instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. The greatly reduced thermal backgrounds achievable on a space platform (compared to airborne or ground-based platforms) allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. We describe results of the development of a new 1024 × 1024 Si:As IBC array with 25-micron pixels that responds with high quantum efficiency over the wavelength range 5 to 28 microns. The previous generation's largest, most sensitive IR detectors at these wavelengths were the 256 × 256/30-micron pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument. JWST MIRI detector requirements will be reviewed and some model results for IBC device performance will be presented. The IBC detector architecture will be described and the SB305 Readout Integrated Circuit (ROIC), developed specifically for JWST MIRI, will be discussed. The SB305 ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 105 electrons. The read noise is expected to be less than 20 e- rms with Fowler-8 sampling at an operating temperature of 7

  17. Evaluation of linear array MOSFET detectors for in vivo dosimetry to measure rectal dose in HDR brachytherapy.

    PubMed

    Haughey, Aisling; Coalter, George; Mugabe, Koki

    2011-09-01

    The study aimed to assess the suitability of linear array metal oxide semiconductor field effect transistor detectors (MOSFETs) as in vivo dosimeters to measure rectal dose in high dose rate brachytherapy treatments. The MOSFET arrays were calibrated with an Ir192 source and phantom measurements were performed to check agreement with the treatment planning system. The angular dependence, linearity and constancy of the detectors were evaluated. For in vivo measurements two sites were investigated, transperineal needle implants for prostate cancer and Fletcher suites for cervical cancer. The MOSFETs were inserted into the patients' rectum in theatre inside a modified flatus tube. The patients were then CT scanned for treatment planning. Measured rectal doses during treatment were compared with point dose measurements predicted by the TPS. The MOSFETs were found to require individual calibration factors. The calibration was found to drift by approximately 1% ±0.8 per 500 mV accumulated and varies with distance from source due to energy dependence. In vivo results for prostate patients found only 33% of measured doses agreed with the TPS within ±10%. For cervix cases 42% of measured doses agreed with the TPS within ±10%, however of those not agreeing variations of up to 70% were observed. One of the most limiting factors in this study was found to be the inability to prevent the MOSFET moving internally between the time of CT and treatment. Due to the many uncertainties associated with MOSFETs including calibration drift, angular dependence and the inability to know their exact position at the time of treatment, we consider them to be unsuitable for in vivo dosimetry in rectum for HDR brachytherapy.

  18. Focal plane array detectors with micro-bolometer structure and its application in IR and THz imaging

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Mou, Wenchao; Gou, Jun; Jiang, Yadong

    2016-10-01

    Focal Plane Array (FPA) detector has characteristics of low cost, operating at room temperature, compatibility with the silicon CMOS technology, and high detecting performance, therefore it becomes a hot spot in infrared (IR) or terahertz (THz) detect field recently. However, the tradition structure of micro-bolometer has the conflict of the pixel size and thermal performance. In order to improve the detecting performance of small pixel size bolometer, high fill factor and low thermal conductance design should be considered. In IR detecting, double layers structure is an efficient method to improve the absorption of micro-bolometer and reduce thermal conductance. The three-dimension model of small size micro-bolometer was built in this article. The thermal and mechanical characters of those models were simulated and optimized, and finally the double layer structure micro-bolometer was fabricated with multifarious semiconductor recipes on the readout integrated chip wafer. For THz detecting, to improve the detecting performance, different dimension THz detectors based on micro-bridge structure were designed and fabricated to get optimizing micro-bolometer parameters from the test results of membrane deformation. A nanostructured titanium thin film absorber is integrated in the micro-bridge structure of the VOx micro-bolometer to enhance the absorption of THz radiation. Continuous-wave THz detection and imaging are demonstrated with a 2.52 THz far infrared CO2 laser and fabricated 320×240 vanadium oxide micro-bolometer focal plane array with optimized cell structure. With this detecting system, THz imaging of metal concealed in wiping cloth and envelope is demonstrated.

  19. Development of Short Wavelength Infrared Array Detectors for Space Astronomy Application

    NASA Technical Reports Server (NTRS)

    Fazio, Giovanni G.

    1997-01-01

    The Smithsonian Astrophysical Observatory (SAO) and its team - the University of Arizona (UA), the University of Rochester (UR), Santa Barbara Research Center (SBRC), Ames Research Center (ARC), and Goddard Space Flight Center (GSFC) - are carrying out a research program with the goal of developing and optimizing infrared arrays in the 2-27 micron range for space infrared astronomy. This report summarizes research results for the entire grant period 1 January 1992 through 30 June 1996.

  20. Radar volume reflectivity estimation using an array of ground-based rainfall drop size detectors

    NASA Astrophysics Data System (ADS)

    Lane, John; Merceret, Francis; Kasparis, Takis; Roy, D.; Muller, Brad; Jones, W. Linwood

    2000-08-01

    Rainfall drop size distribution (DSD) measurements made by single disdrometers at isolated ground sites have traditionally been used to estimate the transformation between weather radar reflectivity Z and rainfall rate R. Despite the immense disparity in sampling geometries, the resulting Z-R relation obtained by these single point measurements has historically been important in the study of applied radar meteorology. Simultaneous DSD measurements made at several ground sites within a microscale area may be used to improve the estimate of radar reflectivity in the air volume surrounding the disdrometer array. By applying the equations of motion for non-interacting hydrometers, a volume estimate of Z is obtained from the array of ground based disdrometers by first calculating a 3D drop size distribution. The 3D-DSD model assumes that only gravity and terminal velocity due to atmospheric drag within the sampling volume influence hydrometer dynamics. The sampling volume is characterized by wind velocities, which are input parameters to the 3D-DSD model, composed of vertical and horizontal components. Reflectivity data from four consecutive WSR-88D volume scans, acquired during a thunderstorm near Melbourne, FL on June 1, 1997, are compared to data processed using the 3D-DSD model and data form three ground based disdrometers of a microscale array.

  1. Measuring extended red sensitivity in a 1.7μm-cutoff HgCdTe detector array

    NASA Astrophysics Data System (ADS)

    Terrien, Ryan C.; Monson, Andrew J.; Mahadevan, Suvrath; Bender, Chad; Halverson, Samuel P.; Ramsey, Larry

    2016-08-01

    Infrared detectors with cutoff wavelengths of 1.7 μm have much lower sensitivity to thermal background contamination than those with longer cutoff wavelengths. This low sensitivity offers the attractive possibility of reducing the need for fully cryogenic systems for YJH-band work, offering the potential for "warm-pupil" instrumentation that nonetheless reduces detected thermal background to the level of dark current. However, residual sensitivity beyond the cutoff wavelength is not well characterized, and may preclude the implementation of such warm-pupil instruments. We describe an experiment to evaluate the long-wavelength sensitivity tail of a 1.7 µm-cutoff HAWAII-2RG array using a thermal blocking filter. Our results suggest the possibility of measurable red sensitivity beyond 2 μm. Ongoing improvements will confirm and refine this measurement. The thermal blocking filter offers the prospect of warm-pupil NIR instrument operation, which is particularly valuable for cost-effective and efficient testing systems: it has facilitated NIR detector characterization and will enable crucial laboratory tests of laser frequency comb calibration systems and other NIR calibration sources.

  2. GABRIELA: A new detector array for γ-ray and conversion electron spectroscopy of transfermium elements

    NASA Astrophysics Data System (ADS)

    Hauschild, K.; Yeremin, A. V.; Dorvaux, O.; Lopez-Martens, A.; Belozerov, A. V.; Briançon, Ch.; Chelnokov, M. L.; Chepigin, V. I.; Garcia-Santamaria, S. A.; Gorshkov, V. A.; Hanappe, F.; Kabachenko, A. P.; Korichi, A.; Malyshev, O. N.; Oganessian, Yu. Ts.; Popeko, A. G.; Rowley, N.; Shutov, A. V.; Stuttgé, L.; Svirikhin, A. I.

    2006-05-01

    With the aid of the Geant4 Monte Carlo simulation package a new detection system has been designed for the focal plane of the recoil separator VASSILISSA situated at the Flerov Laboratory of Nuclear Reactions, JINR, Dubna. GABRIELA ( Gamma Alpha Beta Recoil Investigations with the ELectromagnetic Analyser VASSILISSA) has been optimised to detect the arrival of reaction products and their subsequent radioactive decays involving the emission of α- and β-particles, fission fragments, γ- and X-rays and conversion electrons. The new detector system is described and the results of the first commissioning experiments are presented.

  3. Instrumental performance and results from testing of the BLAST-TNG receiver, submillimeter optics, and MKID detector arrays

    NASA Astrophysics Data System (ADS)

    Galitzki, Nicholas; Ade, Peter; Angilè, Francesco E.; Ashton, Peter; Austermann, Jason; Billings, Tashalee; Che, George; Cho, Hsiao-Mei; Davis, Kristina; Devlin, Mark; Dicker, Simon; Dober, Bradley J.; Fissel, Laura M.; Fukui, Yasuo; Gao, Jiansong; Gordon, Samuel; Groppi, Christopher E.; Hillbrand, Seth; Hilton, Gene C.; Hubmayr, Johannes; Irwin, Kent D.; Klein, Jeffrey; Li, Dale; Li, Zhi-Yun; Lourie, Nathan P.; Lowe, Ian; Mani, Hamdi; Martin, Peter G.; Mauskopf, Philip; McKenney, Christopher; Nati, Federico; Novak, Giles; Pascale, Enzo; Pisano, Giampaolo; Santos, Fabio P.; Scott, Douglas; Sinclair, Adrian; Soler, Juan D.; Tucker, Carole; Underhill, Matthew; Vissers, Michael; Williams, Paul

    2016-07-01

    Polarized thermal emission from interstellar dust grains can be used to map magnetic fields in star forming molecular clouds and the diffuse interstellar medium (ISM). The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) flew from Antarctica in 2010 and 2012 and produced degree-scale polarization maps of several nearby molecular clouds with arcminute resolution. The success of BLASTPol has motivated a next-generation instrument, BLAST-TNG, which will use more than 3000 linear polarization- sensitive microwave kinetic inductance detectors (MKIDs) combined with a 2.5 m diameter carbon fiber primary mirror to make diffraction-limited observations at 250, 350, and 500 µm. With 16 times the mapping speed of BLASTPol, sub-arcminute resolution, and a longer flight time, BLAST-TNG will be able to examine nearby molecular clouds and the diffuse galactic dust polarization spectrum in unprecedented detail. The 250 μm detec- tor array has been integrated into the new cryogenic receiver, and is undergoing testing to establish the optical and polarization characteristics of the instrument. BLAST-TNG will demonstrate the effectiveness of kilo-pixel MKID arrays for applications in submillimeter astronomy. BLAST-TNG is scheduled to fly from Antarctica in December 2017 for 28 days and will be the first balloon-borne telescope to offer a quarter of the flight for "shared risk" observing by the community.

  4. AACN CSI Academy, part 3: Introducing the Massachusetts CSI Nursing Delirium Collaborative.

    PubMed

    DiLibero, Justin; Edwards, Erica; Hanson, Dave

    2015-11-01

    In the final installment of our three-part series, we reveal how the Boston cohort of the American Association of Critical-Care Nurses (AACN) Clinical Scene Investigator (CSI) Academy launched a collective to improve patient safety and quality outcomes related to delirium.

  5. Progress Towards High-Sensitivity Arrays of Detectors of Sub-mm Radiation using Superconducting Tunnel Junctions with Radio-Frequency Single-Electron Transistors

    NASA Technical Reports Server (NTRS)

    Stevenson, T. R.; Hsieh, W.-T.; Li, M. J.; Stahle, C. M.; Wollack, E. J.; Schoelkopf, R. J.; Krebs, Carolyn (Technical Monitor)

    2002-01-01

    The science drivers for the SPIRIT/SPECS missions demand sensitive, fast, compact, low-power, large-format detector arrays for high resolution imaging and spectroscopy in the far infrared and submillimeter. Detector arrays with 10,000 pixels and sensitivity less than 10(exp 20)-20 W/Hz(exp 20)0.5 are needed. Antenna-coupled superconducting tunnel junction detectors with integrated rf single-electron transistor readout amplifiers have the potential for achieving this high level of sensitivity, and can take advantage of an rf multiplexing technique when forming arrays. The device consists of an antenna structure to couple radiation into a small superconducting volume and cause quasiparticle excitations, and a single-electron transistor to measure currents through tunnel junction contacts to the absorber volume. We will describe optimization of device parameters, and recent results on fabrication techniques for producing devices with high yield for detector arrays. We will also present modeling of expected saturation power levels, antenna coupling, and rf multiplexing schemes.

  6. A method to improve fluence resolution derived from two-dimensional detector array measurements for patient-specific IMRT verification using the information collected in dynalog files

    PubMed Central

    Santiago, Juan Agustin Calama; Utrilla, Miguel Angel Infante; Rodriguez, Maria Elisa Lavado

    2015-01-01

    This paper proposes a method for improving the resolution of the fluence derived from detector array measurement using the information collected in dynalog files. From dynalog information, a file is generated with the actual multileaf collimator (MLC) positions and used as input to the treatment planning system (TPS) to obtain the dynalog-derived fluence and the theoretical response over the detector array. In contrast with the measured response, this theoretical response allows for correction of the dynalog-derived fluence and translation into the reconstructed fluence. This fluence is again introduced into the planning system to verify the treatment using clinical tools. Initially, more than 98% of the points passed the two-dimensional (2D) phantom gamma test (3% local dose - 3 mm) for all of the treatment verifications, but in some dose–volume histogram (DVH) comparisons, we note sensitive differences for the planning target volume (PTV) coverage and for the maximum doses in at-risk organs (up to 3.5%). In dose–distribution evaluations, we found differences of up to 5% in the PTV edges in certain cases due to detector array measurement errors. This work improves the resolution of the fluence derived from detector array measurements based on the treatment information, in contrast with the current commercial proposals based on planned data. PMID:26150681

  7. Evaluation of InGaAs 640×512 detector array manufactured by Chunghwa Leading Photonics Tech

    NASA Astrophysics Data System (ADS)

    Nagayama, Takahiro; Takeuchi, Nami; Kokusho, Takuma; Yamanaka, Asa; Nishiyama, Miho; Kaneda, Hidehiro

    2014-07-01

    Focal Plane Arrays (FPA) are key items for modern astronomical observations in the near infrared wavelength, but it is very expensive and not easy to get them. Less expensive NIR FPAs with reasonable performance are very important to spread NIR observation extensively. FPA640×512 manufactured by Chunghwa Leading Photonics Tech is a 640×512 InGaAs detector covering the 0.9-1.7 μm wavelength. Since this array is significantly cheaper than the commonly used NIR FPAs in the astronomical observation, it is possible to be a good choice for particular projects which do not need many pixels, if FPA640×512 has acceptable performance for the purpose. We have evaluated one test grade array of FPA640×512 both in the room and low temperature environment. In order to evaluate the characteristics of this FPA in the low temperature environment, we cooled it down by the mechanical refrigerator and confirmed that it works at 100 K. We have found that the dark current reduces exponentially as the FPA temperature decreases, but it hits the bottom at~1000 e-/sec bellow 200 K with the default setting. We are trying to reduce the dark current by optimizing the bias voltage and the current to the MUX circuit. The latest experiments have shown the possibility that the dark current decreases to~200 e-/sec. This value is still higher than that of NIR FPAs used in the scientific observation, but it may be applicable for the particular purpose, for example, FPAs for slit viewer in spectrometers, wave front sensor, and so on.

  8. Sub-200 ps CRT in monolithic scintillator PET detectors using digital SiPM arrays and maximum likelihood interaction time estimation.

    PubMed

    van Dam, Herman T; Borghi, Giacomo; Seifert, Stefan; Schaart, Dennis R

    2013-05-21

    Digital silicon photomultiplier (dSiPM) arrays have favorable characteristics for application in monolithic scintillator detectors for time-of-flight positron emission tomography (PET). To fully exploit these benefits, a maximum likelihood interaction time estimation (MLITE) method was developed to derive the time of interaction from the multiple time stamps obtained per scintillation event. MLITE was compared to several deterministic methods. Timing measurements were performed with monolithic scintillator detectors based on novel dSiPM arrays and LSO:Ce,0.2%Ca crystals of 16 × 16 × 10 mm(3), 16 × 16 × 20 mm(3), 24 × 24 × 10 mm(3), and 24 × 24 × 20 mm(3). The best coincidence resolving times (CRTs) for pairs of identical detectors were obtained with MLITE and measured 157 ps, 185 ps, 161 ps, and 184 ps full-width-at-half-maximum (FWHM), respectively. For comparison, a small reference detector, consisting of a 3 × 3 × 5 mm(3) LSO:Ce,0.2%Ca crystal coupled to a single pixel of a dSiPM array, was measured to have a CRT as low as 120 ps FWHM. The results of this work indicate that the influence of the optical transport of the scintillation photons on the timing performance of monolithic scintillator detectors can at least partially be corrected for by utilizing the information contained in the spatio-temporal distribution of the collection of time stamps registered per scintillation event.

  9. Adaptive optics wavefront sensors based on photon-counting detector arrays

    NASA Astrophysics Data System (ADS)

    Aull, Brian F.; Schuette, Daniel R.; Reich, Robert K.; Johnson, Robert L.

    2010-07-01

    For adaptive optics systems, there is a growing demand for wavefront sensors that operate at higher frame rates and with more pixels while maintaining low readout noise. Lincoln Laboratory has been investigating Geiger-mode avalanche photodiode arrays integrated with CMOS readout circuits as a potential solution. This type of sensor counts photons digitally within the pixel, enabling data to be read out at high rates without the penalty of readout noise. After a brief overview of adaptive optics sensor development at Lincoln Laboratory, we will present the status of silicon Geigermode- APD technology along with future plans to improve performance.

  10. Label-free silicon photonic biosensor system with integrated detector array.

    PubMed

    Yan, Rongjin; Mestas, Santano P; Yuan, Guangwei; Safaisini, Rashid; Dandy, David S; Lear, Kevin L

    2009-08-07

    An integrated, inexpensive, label-free photonic waveguide biosensor system with multi-analyte capability has been implemented on a silicon photonics integrated circuit from a commercial CMOS line and tested with nanofilms. The local evanescent array coupled (LEAC) biosensor is based on a new physical phenomenon that is fundamentally different from the mechanisms of other evanescent field sensors. Increased local refractive index at the waveguide's upper surface due to the formation of a biological nanofilm causes local modulation of the evanescent field coupled into an array of photodetectors buried under the waveguide. The planar optical waveguide biosensor system exhibits sensitivity of 20%/nm photocurrent modulation in response to adsorbed bovine serum albumin (BSA) layers less than 3 nm thick. In addition to response to BSA, an experiment with patterned photoresist as well as beam propagation method simulations support the evanescent field shift principle. The sensing mechanism enables the integration of all optical and electronic components for a multi-analyte biosensor system on a chip.

  11. Spectral-domain phase microscopy with improved sensitivity using two-dimensional detector arrays

    SciTech Connect

    Singh, K.; Dion, C.; Ozaki, T.; Lesk, M. R.; Costantino, S.

    2011-02-15

    In this work we demonstrate the use of two-dimensional detectors to improve the signal-to-noise ratio (SNR) and sensitivity in spectral-domain phase microscopy for subnanometer accuracy measurements. We show that an increase in SNR can be obtained, from 82 dB to 105 dB, using 150 pixel lines of a low-cost CCD camera as compared to a single line, to compute an averaged axial scan. In optimal mechanical conditions, phase stability as small as 92 {mu}rad, corresponding to 6 pm displacement accuracy, could be obtained. We also experimentally demonstrate the benefit of spatial-averaging in terms of the reduction of signal fading due to an axially moving sample. The applications of the improved system are illustrated by imaging live cells in culture.

  12. Experiment and simulation for CSI: What are the missing links?

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith; Park, K. C.

    1989-01-01

    Viewgraphs on experiment and simulation for control structure interaction (CSI) are presented. Topics covered include: control structure interaction; typical control/structure interaction system; CSI problem classification; actuator/sensor models; modeling uncertainty; noise models; real-time computations; and discrete versus continuous.

  13. A spaceborne optical interferometer: The JPL CSI mission focus

    NASA Technical Reports Server (NTRS)

    Laskin, R. A.

    1989-01-01

    The JPL Control Structure Interaction (CSI) program is part of the larger NASA-wide CSI program. Within this larger context, the JPL CSI program will emphasize technology for systems that demand micron or sub-micron level control, so-called Micro-Precision Controlled Structures (u-PCS). The development of such technology will make it practical to fly missions with large optical or large precision antenna systems. In keeping with the focused nature of the desired technology, the JPL approach is to identify a focus mission, develop the focus mission CSI system design to a preliminary level, and then use this design to drive out requirements for CSI technology development in the design and analysis, ground test bed, and flight experiment areas.

  14. A Low-Power, Radiation-Resistant, Silicon-Drift-Detector Array for Extraterrestrial Element Mapping

    SciTech Connect

    Ramsey B. D.; De Geronimo G.; Gaskin, J.A.; Elsner, R.F.; Chen, W.; Carini, G.A.; Keister, J.; Li, S.; Li, Z.; Siddons, D.P.; Smith, G.

    2012-02-08

    We are developing a modular Silicon Drift Detector (SDD) X-Ray Spectrometer (XRS) for measuring the abundances of light surface elements (C to Fe) fluoresced by ambient radiation on remote airless bodies. The value of fluorescence spectrometry for surface element mapping is demonstrated by its inclusion on three recent lunar missions and by exciting new data that have recently been announced from the Messenger Mission to Mercury. The SDD-XRS instrument that we have been developing offers excellent energy resolution and an order of magnitude lower power requirement than conventional CCDs, making much higher sensitivities possible with modest spacecraft resources. In addition, it is significantly more radiation resistant than x-ray CCDs and therefore will not be subject to the degradation that befell recent lunar instruments. In fact, the intrinsic radiation resistance of the SDD makes it applicable even to the harsh environment of the Jovian system where it can be used to map the light surface elements of Europa. In this paper, we first discuss our element-mapping science-measurement goals. We then derive the necessary instrument requirements to meet these goals and discuss our current instrument development status with respect to these requirements.

  15. Role of the retinal detector array in perceiving the superposition effects of light

    NASA Astrophysics Data System (ADS)

    Roychoudhuri, Chandrasekhar; Lakshminarayanan, Vasudevan

    2006-08-01

    The perception of light in nature comes through the photopigment molecules of our retina. The objective of this paper is to relate our modern understanding of the quantum mechanical chemical processes in the retinal molecules with our observation of superposition ("interference") fringes due to multiple light beams. The issue of "interference" is important for two subtle reasons. First, we do not perceive light except though the response of the light detecting molecules. Second, EM fields do not operate on each other to create the "interference" (superposition) effects. When the intrinsic molecular properties of a detector allows it to respond simultaneously to all the superposed light beams on them, they sum the effects and report the corresponding "fringes" of superposition. In the human eye the "seeing" (or perception) is initiated by photo-isomerization of retinal, the chromophore of the opsin molecule. There exists several orders of magnitude difference between the characteristic times for the molecular processes of light absorption and the visual signal generation through the photochemical cascade. This allows us to function in the daily chores of walking and visual identification of objects and enjoy the beauty of the natural sceneries even though the retinal layer is bombarded simultaneously by innumerable beams of light with same and different frequencies, which will normally produce a flood of electronic "white noise" over a very wide range of temporal frequencies, namely the heterodyne beat signal. How do the eyes completely suppress this wide range of heterodyne beat signal?

  16. Spectral light measurements in microbenthic phototrophic communities with a fiber-optic microprobe coupled to a sensitive diode array detector

    SciTech Connect

    Kuehl, M. ); Joergensen, B.B. )

    1992-12-01

    A diode array detector system for microscale light measurements with fiber-optic microprobes was developed; it measures intensities of 400-900-nm light over >6 orders of magnitude with a spectral resolution of 2-5 nm. Fiber-optic microprobes to measure field radiance or scalar irradiance were coupled to the detector system and used for spectral light measurements in hypersaline microbial mats and in laminated phototrophic communities of coastal sediments. The vertical distribution of major photopigments of microalgae, cyanobacteria, and anoxygenic phototrophic bacteria could be identified from extinction maxima in measured radiance spectra at 430-550 nm (Chl a and carotenoids), 620-625 nm (phycocyanin), 675 nm (Chl a), 745-750 nm (BChl c), 800-810 nm, and 860-880 nm (BChl a). Scalar irradiance spectra exhibited a different spectral composition and a higher light intensity at the sediment surface as compared to incident light. IR light thus reached 200% of incident at the sediment surface. Maximal light penetration was found for IR light, whereas visible light was strongly attenuated in the upper 0-2 mm of the sediment. Measurements of photon scalar irradiance (400-700 nm) were combined with microelectrode measurements of oxygenic photosynthesis in the coastal sediment. With an incident light intensity of 200 [mu]Einst m[sup [minus]2]s[sup [minus]1], photon scalar irradiance reached a maximum of 283 [mu]Einst m[sup [minus]2]s[sup [minus]1] at the sediment surface. The lower boundary of the euphotic zone was 2.2 mm below the surface at a light intensity of 12 [mu]Einst m[sup [minus]2]s[sup [minus]1]. 20 refs., 6 figs.

  17. In-beam measurements of sub-nanosecond nuclear lifetimes with a mixed array of HPGe and LaBr3:Ce detectors

    NASA Astrophysics Data System (ADS)

    Mărginean, N.; Balabanski, D. L.; Bucurescu, D.; Lalkovski, S.; Atanasova, L.; Căta-Danil, G.; Căta-Danil, I.; Daugas, J. M.; Deleanu, D.; Detistov, P.; Deyanova, G.; Filipescu, D.; Georgiev, G.; Ghiţă, D.; Gladnishki, K. A.; Lozeva, R.; Glodariu, T.; Ivaşcu, M.; Kisyov, S.; Mihai, C.; Mărginean, R.; Negret, A.; Pascu, S.; Radulov, D.; Sava, T.; Stroe, L.; Suliman, G.; Zamfir, N. V.

    2010-12-01

    A fast-timing method to determine lifetimes of nuclear states in the sub-nanosecond domain is presented. It is based on in-beam measurements of triple-gamma coincidences in heavy-ion fusion-evaporation reactions, performed with an array of HPGe and LaBr3:Ce detectors. The high-energy resolution HPGe detectors are used to define de-exciting cascades, while the fast LaBr3:Ce detectors are used to determine the decay time spectra of selected levels fed by these cascades. A special method to treat the time information of an array of fast detectors is employed in order to fully use the efficiency of the array. Two measurements are presented to illustrate the method: a re-determination of the known half-life ensuremath T_{1/2}=0.7 ns of the ensuremath E_x=205 keV, ensuremath J^{π}=7/2^+ level in 107Cd (test experiment), and the determination of a half-life ensuremath T_{1/2}=47 ps for the ensuremath E_x=367 keV, ensuremath J^{π}=3/2^+ state of 199Tl.

  18. Buffer direct injection readout integrated circuit design for dual band infrared focal plane array detector

    NASA Astrophysics Data System (ADS)

    Sun, Tai-Ping; Lu, Yi-Chuan; Shieh, Hsiu-Li; Tang, Shiang-Feng; Lin, Wen-Jen

    2013-05-01

    This paper proposes dual-mode buffer direct injection (BDI) and direct injection (DI) readout circuit design. The DI readout circuit has the advantage of being a simple circuit, requiring a small layout area, and low power consumption. The internal resistance of the photodetector will affect the photocurrent injection efficiency. We used a buffer amplifier to design the BDI readout circuit since it would reduce the input impedance and raise the injection efficiency. This paper will discuss and analyze the power consumption, injection efficiency, layout area, and circuit noise. The circuit is simulated using a TSMC 0.35 um Mixed Signal 2P4M CMOS 5 V process. The dimension of the pixel area is 30×30 μm. We have designed a 10×8 array for the readout circuit of the interlaced columns. The input current ranges from 1 nA to 10 nA, when the measurement current is 10 pA to 10 nA. The integration time was varied. The circuit output swing was 2 V. The total root mean square noise voltage was 4.84 mV. The signal to noise ratio was 52 dB, and the full chip circuit power consumption was 9.94 mW.

  19. Final report on LDRD project : single-photon-sensitive imaging detector arrays at 1600 nm.

    SciTech Connect

    Childs, Kenton David; Serkland, Darwin Keith; Geib, Kent Martin; Hawkins, Samuel D.; Carroll, Malcolm S.; Klem, John Frederick; Sheng, Josephine Juin-Jye; Patel, Rupal K.; Bolles, Desta; Bauer, Tom M.; Koudelka, Robert

    2006-11-01

    The key need that this project has addressed is a short-wave infrared light detector for ranging (LIDAR) imaging at temperatures greater than 100K, as desired by nonproliferation and work for other customers. Several novel device structures to improve avalanche photodiodes (APDs) were fabricated to achieve the desired APD performance. A primary challenge to achieving high sensitivity APDs at 1550 nm is that the small band-gap materials (e.g., InGaAs or Ge) necessary to detect low-energy photons exhibit higher dark counts and higher multiplication noise compared to materials like silicon. To overcome these historical problems APDs were designed and fabricated using separate absorption and multiplication (SAM) regions. The absorption regions used (InGaAs or Ge) to leverage these materials 1550 nm sensitivity. Geiger mode detection was chosen to circumvent gain noise issues in the III-V and Ge multiplication regions, while a novel Ge/Si device was built to examine the utility of transferring photoelectrons in a silicon multiplication region. Silicon is known to have very good analog and GM multiplication properties. The proposed devices represented a high-risk for high-reward approach. Therefore one primary goal of this work was to experimentally resolve uncertainty about the novel APD structures. This work specifically examined three different designs. An InGaAs/InAlAs Geiger mode (GM) structure was proposed for the superior multiplication properties of the InAlAs. The hypothesis to be tested in this structure was whether InAlAs really presented an advantage in GM. A Ge/Si SAM was proposed representing the best possible multiplication material (i.e., silicon), however, significant uncertainty existed about both the Ge material quality and the ability to transfer photoelectrons across the Ge/Si interface. Finally a third pure germanium GM structure was proposed because bulk germanium has been reported to have better dark count properties. However, significant

  20. Development of high resolution imaging detectors for x ray astronomy

    NASA Technical Reports Server (NTRS)

    Murray, S. S.; Schwartz, D. A.

    1992-01-01

    This final report summarizes our past activities and discusses the work performed over the period of 1 April 1990 through 1 April 1991 on x-ray optics, soft x-ray (0.1 - 10 KeV) imaging detectors, and hard x-ray (10 - 300 KeV) imaging detectors. If microchannel plates (MCPs) can be used to focus x-rays with a high efficiency and good angular resolution, they will revolutionize the field of x-ray optics. An x-ray image of a point source through an array of square MCP pores compared favorably with our ray tracing model for the MCP. Initial analysis of this image demonstrates the feasibility of MCPs for soft x-rays. Our work continues with optimizing the performance of our soft x-ray MCP imaging detectors. This work involves readout technology that should provide improved MCP readout devices (thin film crossed grid, curved, and resistive sheets), defect removal in MCPs, and photocathode optimization. In the area of hard x-ray detector development we have developed two different techniques for producing a CsI photocathode thickness of 10 to 100 microns, such that it is thick enough to absorb the high energy x-rays and still allow the photoelectrons to escape to the top MCP of a modified soft x-ray imaging detector. The methods involve vacuum depositing a thick film of CsI on a strong back, and producing a converter device that takes the place of the photocathode.

  1. Linear terrestrial laser scanning using array avalanche photodiodes as detectors for rapid three-dimensional imaging.

    PubMed

    Cai, Yinqiao; Tong, Xiaohua; Tong, Peng; Bu, Hongyi; Shu, Rong

    2010-12-01

    As an active remote sensor technology, the terrestrial laser scanner is widely used for direct generation of a three-dimensional (3D) image of an object in the fields of geodesy, surveying, and photogrammetry. In this article, a new laser scanner using array avalanche photodiodes, as designed by the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences, is introduced for rapid collection of 3D data. The system structure of the new laser scanner is first presented, and a mathematical model is further derived to transform the original data to the 3D coordinates of the object in a user-defined coordinate system. The performance of the new laser scanner is tested through a comprehensive experiment. The result shows that the new laser scanner can scan a scene with a field view of 30° × 30° in 0.2 s and that, with respect to the point clouds obtained on the wall and ground floor surfaces, the root mean square errors for fitting the two planes are 0.21 and 0.01 cm, respectively. The primary advantages of the developed laser scanner include: (i) with a line scanning mode, the new scanner achieves simultaneously the 3D coordinates of 24 points per single laser pulse, which enables it to scan faster than traditional scanners with a point scanning mode and (ii) the new scanner makes use of two galvanometric mirrors to deflect the laser beam in both the horizontal and the vertical directions. This capability makes the instrument smaller and lighter, which is more acceptable for users.

  2. Beam tests of a MWPC with CsI photocathode for Cherenkov Ring Imaging

    SciTech Connect

    Krizan, P.; Staric, M.; Stanovnik, A.; Cindro, M.; Skrk, D.; Zavrtanik, M.; Korpar, S.; Hamacher, T.; Michel, E.

    1995-08-01

    A 24 x 24 cm{sup 2} asymmetric multiwire proportional chamber, with 7.5 x 7.5 mm{sup 2} photosensitive CsI pads, has been tested with Cherenkov radiation of 3 GeV/c electrons in the T24 test beam at DESY. The performance of the chamber with specially designed low-noise, charge-sensitive preamplifiers is described. The parameters of the CsI-MWPC are compared to those of a TMAE photon detector in order to evaluate their potential as Ring Imaging Cherenkov (RICH) counters for the HERA-B experiment at DESY.

  3. Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time

    PubMed Central

    Zhang, Qingteng; Dufresne, Eric M.; Grybos, Pawel; Kmon, Piotr; Maj, Piotr; Narayanan, Suresh; Deptuch, Grzegorz W.; Szczygiel, Robert; Sandy, Alec

    2016-01-01

    Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. The potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed. PMID:27140146

  4. Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time

    DOE PAGES

    Zhang, Qingteng; Dufresne, Eric M.; Grybos, Pawel; ...

    2016-01-01

    Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. As a result, the potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

  5. Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time

    SciTech Connect

    Zhang, Qingteng; Dufresne, Eric M.; Grybos, Pawel; Kmon, Piotr; Maj, Piotr; Narayanan, Suresh; Deptuch, Grzegorz W.; Szczygiel, Robert; Sandy, Alec

    2016-01-01

    Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. As a result, the potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

  6. High Throughput, High Yield Fabrication of High Quantum Efficiency Back-Illuminated Photon Counting, Far UV, UV, and Visible Detector Arrays

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh; Hoenk, M. E.; Carver, A. G.; Jones, T. J.; Greer, F.; Hamden, E.; Goodsall, T.

    2013-01-01

    In this paper we discuss the high throughput end-to-end post fabrication processing of high performance delta-doped and superlattice-doped silicon imagers for UV, visible, and NIR applications. As an example, we present our results on far ultraviolet and ultraviolet quantum efficiency (QE) in a photon counting, detector array. We have improved the QE by nearly an order of magnitude over microchannel plates (MCPs) that are the state-of-the-art UV detectors for many NASA space missions as well as defense applications. These achievements are made possible by precision interface band engineering of Molecular Beam Epitaxy (MBE) and Atomic Layer Deposition (ALD).

  7. Measurement of effect of electron cyclotron heating in a tandem mirror plasma using a semiconductor detector array and an electrostatic energy analyzer

    NASA Astrophysics Data System (ADS)

    Minami, R.; Imai, T.; Kariya, T.; Numakura, T.; Uehara, M.; Tsumura, K.; Ebashi, Y.; Kajino, S.; Endo, Y.; Nakashima, Y.

    2016-11-01

    Temporally and spatially resolved soft x-ray and end-loss-electron analyses of the electron cyclotron heated plasmas are carried out by using a semiconductor detector array and an electrostatic energy analyzer in the GAMMA 10 tandem mirror. The flux and the energy spectrum of the end loss electrons are measured by a multi-grid energy analyzer. Recently, the electron cyclotron heating power modulation experiments have been started in order to generate and control the high heat flux and to make the edge localized mode-like intermittent heat load pattern for the divertor simulation studies by the use of these detectors for electron properties.

  8. Quantitative analysis and chromatographic fingerprinting for the quality evaluation of Forsythia suspensa extract by HPLC coupled with photodiode array detector.

    PubMed

    Xia, Yonggang; Yang, Bingyou; Wang, Qiuhong; Liang, Jun; Wei, Youhe; Yu, Hedan; Zhang, Qingbo; Kuang, Haixue

    2009-12-01

    A simple and reproducible HPLC-photodiode array detector method has been described for evaluating and controlling quality of Forsythia suspensa extract (FSE). First, by analysis of chromatographic fingerprints, the similarities of chromatograms of FSE samples from the same pharmaceutical company exceeded 0.999, 0.997 and 0.960, respectively, although they were much lower from different pharmaceutical companies. Second, by further comparing many batches of extract chromatograph charts with the corresponding reference herb materials, the "common peaks" 3, 5, 7 and 10 were defined as "marker peaks", which were identified as (+)-pinoresinol-beta-D-glucoside, forsythiaside, phillyrin and phillygenin, respectively. Third, four "marker peaks" were simultaneously determined based on fingerprint chromatogram for further controlling the quality of FSE quantitatively. Namely, the newly developed method was successfully applied to analyze 38 batches of FSE samples supplied by three pharmaceutical factories, which showed acceptable linearity, intra-day precision (RSD<2.76%), inter-day precision (RSD<3.43%) and the average recovery rates in the range of (95.38+/-2.96)% to (101.60+/-3.08)%. At last, hierarchical clustering analysis and Bayes discriminant analysis statistical methods were used to classify and differentiate the 38 FSE samples to provide the basis for guiding reasonable use of FSE and controlling its quality better.

  9. Screening method for the determination of tetracyclines and fluoroquinolones in animal drinking water by liquid chromatography with diode array detector.

    PubMed

    Patyra, E; Kowalczyk, E; Grelik, A; Przeniosło-Siwczyńska, M; Kwiatek, K

    2015-01-01

    A liquid chromatography - diode array detector (HPLC-DAD) procedure has been developed for the determination of oxytetracycline (OTC), tetracycline (TC), chlorotetracycline (CTC), doxycycline (DC), enrofloxacin (ENR), ciprofloxacin (CIP), sarafloxacin (SAR) and flumequine (FLU) residues in animal drinking water. This method was applied to animal drinking water. Solid-phase extraction (SPE) clean-up on an Oasis HLB cartridge allowed an extract suitable for liquid chromatographic analysis to be obtained. Chromatographic separation was carried out on a C18 analytical column, using gradient elution with 0.1% trifluoroacetic acid - acetonitrile - methanol at 30°C. The flow-rate was 0.7 mL/min and the eluate was analysed at 330 nm. The whole procedure was evaluated according to the requirements of the Commission Decision 2002/657/EC, determining specificity, decision limit (CCα), detection capacity (CCβ), limit of detection (LOD), limit of quantification (LOQ), precision and accuracy during validation of the method. The recoveries of TCs and FQs from spiked samples at the levels of 10, 100 and 1000 μg/L were higher than 82%. The developed method based on HPLC-DAD has been applied for the determination of four tetracyclines and four fluoroquinolones in animal drinking water samples.

  10. Application of RP-HPLC-diode array detector after SPE to the determination of pesticides in pepper samples.

    PubMed

    Tuzimski, Tomasz

    2012-01-01

    The application of HPLC-diode array detector (DAD) after SPE for identification and quantitative analysis of pesticides in red and green pepper samples is demonstrated. An HPLC procedure on an RP column (C18) was developed for analysis of selected pesticides from different chemical groups: metamitron, metalaxyl, linuron, and prometryn. Average recoveries for C18 Polar Plus cartridges and solvents by the proposed RP-HPLC-DAD method after SPE are presented. Average recoveries from the spiked samples and the SDs were 22.5 +/- 2.2, 138.0 +/- 4.1, 78.6 +/- 2.8, and 109.2 +/- 2.3% for metamitron, metalaxyl, linuron, and prometryn, respectively, at concentrations of 7 microg/g in the plant material. The efficiency of the SPE procedure was evaluated using real food samples. The quantities of prometryn, linuron, metalaxyl, and metamitron determined were in the ranges of 0.02-2.24 microg/g (n = 24), 0.08-1.01 microg/g (n = 9), 1.61-2.28 microg/g (n=4), and 0.05-1.07 microg/g (n = 3), respectively, in plant material sampled in 2011. The method was validated for precision, repeatability, and accuracy.

  11. Fingerprint Analysis of Desmodium Triquetrum L. Based on Ultra Performance Liquid Chromatography with Photodiode Array Detector Combined with Chemometrics Methods.

    PubMed

    Zhang, Meiling; Zhao, Cui; Liang, Xianrui; Ying, Yin; Han, Bing; Yang, Bo; Jiang, Cheng

    2016-01-01

    A fingerprinting approach was developed by means of ultra high-performance liquid chromatography with photodiode array detector for the quality control of Desmodium triquetrum L., an herbal medicine widely used for clinical purposes. Ten batches of raw material samples of D. triquetrum were collected from different regions of China. All UPLC analyses were carried out on a Waters ACQUITY UPLC BEH shield RP18 column (2.1 × 50 mm, 1.7 µm particle size) at 60°C, with a gradient mobile phase composed of 0.1% aqueous formic acid and acetonitrile at a flow rate of 0.45 mL/min. The method validation results demonstrated the developed method possessing desirable reproducibility, efficiency, and allowing fingerprint analysis in one chromatographic run within 13 min. The quality assessment was achieved by using chemometrics methods including similarity analysis, hierarchical clustering analysis and principal component analysis. The developed method can be used for further quality control of D. triquetrum.

  12. Gravitational-Wave Tests of General Relativity with Ground-Based Detectors and Pulsar-Timing Arrays.

    PubMed

    Yunes, Nicolás; Siemens, Xavier

    2013-01-01

    This review is focused on tests of Einstein's theory of general relativity with gravitational waves that are detectable by ground-based interferometers and pulsar-timing experiments. Einstein's theory has been greatly constrained in the quasi-linear, quasi-stationary regime, where gravity is weak and velocities are small. Gravitational waves will allow us to probe a complimentary, yet previously unexplored regime: the non-linear and dynamical strong-field regime. Such a regime is, for example, applicable to compact binaries coalescing, where characteristic velocities can reach fifty percent the speed of light and gravitational fields are large and dynamical. This review begins with the theoretical basis and the predicted gravitational-wave observables of modified gravity theories. The review continues with a brief description of the detectors, including both gravitational-wave interferometers and pulsar-timing arrays, leading to a discussion of the data analysis formalism that is applicable for such tests. The review ends with a discussion of gravitational-wave tests for compact binary systems.

  13. Visualization of tumor-related blood vessels in human breast by photoacoustic imaging system with a hemispherical detector array

    PubMed Central

    Toi, M.; Asao, Y.; Matsumoto, Y.; Sekiguchi, H.; Yoshikawa, A.; Takada, M.; Kataoka, M.; Endo, T.; Kawaguchi-Sakita, N.; Kawashima, M.; Fakhrejahani, E.; Kanao, S.; Yamaga, I.; Nakayama, Y.; Tokiwa, M.; Torii, M.; Yagi, T.; Sakurai, T.; Togashi, K.; Shiina, T.

    2017-01-01

    Noninvasive measurement of the distribution and oxygenation state of hemoglobin (Hb) inside the tissue is strongly required to analyze the tumor-associated vasculatures. We developed a photoacoustic imaging (PAI) system with a hemispherical-shaped detector array (HDA). Here, we show that PAI system with HDA revealed finer vasculature, more detailed blood-vessel branching structures, and more detailed morphological vessel characteristics compared with MRI by the use of breast shape deformation of MRI to PAI and their fused image. Morphologically abnormal peritumoral blood vessel features, including centripetal photoacoustic signals and disruption or narrowing of vessel signals, were observed and intratumoral signals were detected by PAI in breast cancer tissues as a result of the clinical study of 22 malignant cases. Interestingly, it was also possible to analyze anticancer treatment-driven changes in vascular morphological features and function, such as improvement of intratumoral blood perfusion and relevant changes in intravascular hemoglobin saturation of oxygen. This clinical study indicated that PAI appears to be a promising tool for noninvasive analysis of human blood vessels and may contribute to improve cancer diagnosis. PMID:28169313

  14. Commissioning the DANTE array of BaF2 detectors at TRIUMF-ISAC using a fast-timing lifetime measurement

    NASA Astrophysics Data System (ADS)

    Cross, D. S.; Ball, G. C.; Garrett, P. E.; Triambak, S.; Williams, S. J.; Andreoiu, C.; Churchman, R.; Garnsworthy, A. B.; Hackman, G.; Leslie, J. R.; Orce, J. N.; Sumithrarachchi, C. S.; Svensson, C. E.

    2011-08-01

    The Di-pentagonal Array for Nuclear Timing Experiments (DANTE) is an array of ten BaF2 detectors used in conjunction with the 8π gamma-ray spectrometer at the TRIUMF-ISAC radioactive-ion beam facility. DANTE is used to conduct direct lifetime measurements of nuclear excited states in the picosecond - nanosecond range. This, in turn, will aid in probing the collective structures of deformed nuclei. The capability of DANTE to measure nanosecond-scale lifetimes is demonstrated by using a 152Eu source. The half-life of the Iπ = 21+ state of 152Sm is measured to be 1.426 ± 0.018 ns.

  15. Gaseous detectors of ultraviolet and visible photons

    SciTech Connect

    Peskov, V.; Borovik-Romanov, A.; Volynshikova, T.

    1994-06-01

    We describe simple methods of manufacturing in a laboratory gaseous detectors of visible photons with GaAs(Cs) and SbCs photocathodes and Ti getters. Covered by CsI protective layers they are robust enough to be stable under ordinary experimental conditions. First attempts to use these detectors for crystal scintillator and fiber readout are presented.

  16. Progress Towards High-Sensitivity Arrays of Detectors of Sub-mm Radiation Using Superconducting Tunnel Junctions with Integrated Radio Frequency Single-Electron Transistors

    NASA Technical Reports Server (NTRS)

    Stevenson, T. R.; Hsieh, W.-T.; Li, M. J.; Prober, D. E.; Rhee, K. W.; Schoelkopf, R. J.; Stahle, C. M.; Teufel, J.; Wollack, E. J.

    2004-01-01

    For high resolution imaging and spectroscopy in the FIR and submillimeter, space observatories will demand sensitive, fast, compact, low-power detector arrays with 104 pixels and sensitivity less than 10(exp -20) W/Hz(sup 0.5). Antenna-coupled superconducting tunnel junctions with integrated rf single-electron transistor readout amplifiers have the potential for achieving this high level of sensitivity, and can take advantage of an rf multiplexing technique. The device consists of an antenna to couple radiation into a small superconducting volume and cause quasiparticle excitations, and a single-electron transistor to measure current through junctions contacting the absorber. We describe optimization of device parameters, and results on fabrication techniques for producing devices with high yield for detector arrays. We also present modeling of expected saturation power levels, antenna coupling, and rf multiplexing schemes.

  17. Nuclear resonant scattering measurements on {sup 57}Fe by multichannel scaling with a 64-pixel silicon avalanche photodiode linear-array detector

    SciTech Connect

    Kishimoto, S. Haruki, R.; Mitsui, T.; Yoda, Y.; Taniguchi, T.; Shimazaki, S.; Ikeno, M.; Saito, M.; Tanaka, M.

    2014-11-15

    We developed a silicon avalanche photodiode (Si-APD) linear-array detector for use in nuclear resonant scattering experiments using synchrotron X-rays. The Si-APD linear array consists of 64 pixels (pixel size: 100 × 200 μm{sup 2}) with a pixel pitch of 150 μm and depletion depth of 10 μm. An ultrafast frontend circuit allows the X-ray detector to obtain a high output rate of >10{sup 7} cps per pixel. High-performance integrated circuits achieve multichannel scaling over 1024 continuous time bins with a 1 ns resolution for each pixel without dead time. The multichannel scaling method enabled us to record a time spectrum of the 14.4 keV nuclear radiation at each pixel with a time resolution of 1.4 ns (FWHM). This method was successfully applied to nuclear forward scattering and nuclear small-angle scattering on {sup 57}Fe.

  18. Temperature-sensitive junction transformations for mid-wavelength HgCdTe photovoltaic infrared detector arrays by laser beam induced current microscope

    SciTech Connect

    Qiu, Weicheng; Hu, Weida Lin, Tie; Yin, Fei; Zhang, Bo; Chen, Xiaoshuang; Lu, Wei; Cheng, Xiang'ai Wang, Rui

    2014-11-10

    In this paper, we report on the disappearance of the photosensitive area extension effect and the unusual temperature dependence of junction transformation for mid-wavelength, n-on-p HgCdTe photovoltaic infrared detector arrays. The n-type region is formed by B{sup +} ion implantation on Hg-vacancy-doped p-type HgCdTe. Junction transformations under different temperatures are visually captured by a laser beam induced current microscope. A physical model of temperature dependence on junction transformation is proposed and demonstrated by using numerical simulations. It is shown that Hg-interstitial diffusion and temperature activated defects jointly lead to the p-n junction transformation dependence on temperature, and the weaker mixed conduction compared with long-wavelength HgCdTe photodiode contributes to the disappearance of the photosensitive area extension effect in mid-wavelength HgCdTe infrared detector arrays.

  19. SU-E-T-35: A General Fill Factor Definition Serving to Characterise the MLC Misalignment Detection Capabilities of Two-Dimensional Detector Arrays

    SciTech Connect

    Stelljes, T.S.; Looe, H.K.; Poppe, B.; Harder, D.

    2015-06-15

    Purpose: To present a general definition of the fill factor realistically characterizing the “field coverage”, i.e. the MLC misalignment detection capabilities of a detector array. Methods: According to Gago-Arias et al.{sup 1} the fill factor of a 2D array is defined as the ratio of the area enclosed by the FWHM of the fluence response function KM(x) of a single detector and its cell area defined by the detector spacing. More generally - accounting also for the possible overlap between FWHM’s of neighboured detectors - the fill factor is here defined as that fraction of the sum of the detector cell areas in which a defined MLC misalignment is detectable when the induced percentage signal changes exceed a detection threshold d. Ideally the generalized fill factor may reach 100 %. With user code EGS-chamber and a 2 MeV photon slit beam 0.25 mm wide, both types of the fill factor were calculated for an array with total cell area 100 cm{sup 2} for chamber widths 1–9 mm, using =1mm, d=5%. Results: For single chamber width 5 mm, fill factors were 0.49 (FWHM) and 0.61 (generalized). For chamber width 2 mm the FWHM fill factor was 0.13 whereas the generalized fill factor was 0.32. For chamber widths above 7 mm, the FWHM fill factor exceeds unity, and the general fill factor is exactly 1.00. Conclusions: An updated fill factor definition is introduced which, as a generalization of the FWHM-based definition, more closely estimates the performance of small array chambers and gives a realistic value in the case of overlapping sensitive areas of neighboured chambers. References:{sup 1}A. Gago-Arias, L. Brualla-Gonzalez, D.M. Gonzalez-Castano, F. Gomez, M.S. Garcia, V.L. Vega, J.M. Sueiro, J. Pardo-Montero, “Evaluation of chamber response function influence on IMRT verification using 2D commercial detector arrays,” Phys. Med. Biol. 57, 2005–2020 (2012)

  20. Performance of Sub-Array of ARIANNA Detector Stations during First Year of Operation

    NASA Astrophysics Data System (ADS)

    Tatar, Joulien Erdintch

    The ARIANNA high energy neutrino telescope is designed to search for ultrahigh energy neutrinos produced by the collision of cosmic rays with the cosmic microwave background. ARIANNA exploits the recent development of low noise, low power data acquisition technology to measure the brief radio pulses created by neutrino-induced charged particle showers in the Ross Ice Shelf of Antarctica. Three stations were installed and commissioned in early December 2012 as part of a pilot program to construct a hexagonal array of 7 radio stations. Each station required only 10 Watts of power and operated autonomously using both solar panels and wind generators. In addition, an environmental station was deployed at the ARIANNA site. Data is stored locally and reliably transmitted from Antarctica over high speed wireless internet and Iridium satellite modem during special transmission windows. The wireless internet ceased operation on March 15, corresponding to the fading light condition just before Austral winter. With the aid of wind generation, the stations operated until late May before winter hibernation. Communication was re-established after winter hibernation on September 11, 2013 for three of the four stations. Overall, the stations operated for 65% of the year. The station acquired three types of events: (1) forced, (2) thermal, and (3) signals from an external transmitter, which are called "heartbeat" events. The forced trigger captures the ambient RF conditions at a random snapshot in time. The thermal trigger configuration usually required any 2 of the 4 antenna channels to exceed a voltage level of ˜ 6 · Vrms, where Vrms is the root mean square of the random voltage fluctuations. Individual channel thresholds were adjusted to account for temperature dependences in the electronics. The vast majority of thermal triggers are consistent random gaussian noise expected from thermal processes in the ice and amplifier. Excess power, but no increase is trigger rates, is

  1. The complexity and fractal structures of CSI300 before and after the introduction of CSI300IF

    NASA Astrophysics Data System (ADS)

    He, Xiaoli; Wang, Hongwu; Du, Ziping

    2014-11-01

    This paper employs multifractal detrended fluctuation analysis (MF-DFA) approach to analyze the complexity and fractal structures of China Securities Index 300 (CSI300), which covers the period from April 5, 2006 to May 9, 2014. Through comparing the statistic properties before and after the introduction of CSI300 index futures (CSI300IF), we find that: (1) the price return series exhibits multifractal properties for the two periods; (2) by comparing the efficient measure based on the general Hurst exponent, we find the market becomes more efficient after the introduction of CSI300IF; (3) the width of multifractal spectrum becomes narrower, which means the complexity of the market is decreased. Therefore, the introduction of CSI300IF is beneficial to reduce the risk and increase the efficiency of Chinese securities market. Furthermore, the main sources of multifractality of these time series are examined through the shuffle method, and the results show that before CSI300IF the multifractality is mainly due to the long-range correlation properties between small and large fluctuations, while after CSI300IF it is more due to fat-tailed probability distributions.

  2. Performance of LYSO and CeBr3 crystals readout by silicon photomultiplier arrays as compact detectors for space based applications

    NASA Astrophysics Data System (ADS)

    Kryemadhi, A.; Barner, L.; Grove, A.; Mohler, J.; Sisson, C.; Roth, A.

    2017-02-01

    Space based MeV range gamma rays have been largely unexplored due to the difficulty associated with the measurements; however they address a broad range of astrophysical questions, including indirect searches for dark matter. To address these challenges and yet have compact instruments, the next generation experiments would need detectors with high efficiency, high stopping power, excellent energy resolution, and excellent angular resolution. Fast and bright crystal scintillators coupled to compact photo-detectors are an ideal option. In this work we have investigated the LYSO and CeBr3 crystal scintillators because of their high light yield, fast decay time, and small radiation length. We have used the silicon photomultiplier arrays as photo-detectors because of their small size, simple readout, low voltage operation, and immunity to magnetic fields. We studied the gamma rays response for the 1.6 cm × 1.6 cm × 4.0 cm LYSO crystals and a 1.3 cm × 1.3 cm × 1.3 cm CeBr3 crystal readout by 4 × 4 SensL arrays (ArrayC30035). The crystal self-absorption and timing resolution have been examined along with linearity and energy resolution. The DRS4 evaluation board was used for acquisition of the events.

  3. Influence of the substrate surface texture on the photon-sensitivity stability of CsI thin film photocathodes

    NASA Astrophysics Data System (ADS)

    Nitti, M. A.; Tinti, A.; Valentini, A.; Nappi, E.; Acquafredda, P.; Fanizza, E.; Ingrosso, C.; Pistillo, B. R.; Sardella, E.

    2009-10-01

    A study on the influence of the substrate morphology on the photoemission properties of caesium iodide (CsI) thin film photocathodes, in the range 150-200 nm, has been performed. Various types of conductive substrates, patterned by colloidal lithography, have been compared to the standard printed circuit board (PCB), used for the ALICE experiment at CERN [M.A. Nitti, et al., Nucl. Instr. and Meth. A 523 (2004) 323.]. A correlation between the substrate surface texture and the photoemission stability of the films has been demonstrated. The combination of colloidal lithography and plasma etching, or physical evaporation, allows to create on substrates arrays of nanostructures whose shape and pitch can be controlled by changing some parameters during the patterning process. In order to be comparable with the CsI photoelectron escape length and to preserve the substrate morphology in the film, a layer of 20 nm has been deposited on all the samples. Scanning electron microscopy (SEM) investigations of the colloidal lithography patterned (CLP) substrates have been performed. Atomic force microscopy (AFM) topographic images of the CsI thin film evaporated on PCB and CLP substrates have also been acquired and compared, showing a clear difference in the surface texture. An ageing test, consisting of an air exposure with a relative humidity of about 45% for 24 h, resulted in a higher quantum efficiency stability of textured CsI thin film photocathodes evaporated on nanostructured substrates with respect to those grown on standard PCB ones.

  4. Design and construction of a cosmic ray detector array for the correlation of cosmic ray extensive air showers with lightning strikes

    NASA Astrophysics Data System (ADS)

    Ruse, Aaron Nathan

    The process of lightning initiation is a poorly understood phenomenon. One contending theory suggests that galactic cosmic rays play a role in initiating lightning. This theory is referred to as runaway breakdown (RB). Currently there is no known experimental evidence to support RB. For this thesis, a cosmic ray detector array was designed, constructed, and calibrated in order to gather data to test the RB theory. The goal is to correlate cosmic ray extensive air showers (EAS) with lightning strikes measured by the Oklahoma Lightning Mapping Array (OKLMA). Such a correlation would serve as strong experimental evidence that EAS play an important role in lightning initiation. In order to accomplish this goal, the cosmic ray detectors need to have fast timing for high resolution and be able to distinguish between the secondary hard component (muons) and soft component (electrons/gamma rays) of the EAS. Preliminary data from the detector testing site suggests that the detectors are operating according to the design goals. They are able to resolve individual muon counts and they have measured common phenomena such as radon washout and EAS diurnal variation.

  5. The subtype I-F CRISPR-Cas system influences pathogenicity island retention in Pectobacterium atrosepticum via crRNA generation and Csy complex formation.

    PubMed

    Richter, Corinna; Fineran, Peter C

    2013-12-01

    CRISPR (clustered regularly interspaced short palindromic repeats) arrays and Cas (CRISPR-associated) proteins confer acquired resistance against mobile genetic elements in a wide range of bacteria and archaea. The phytopathogen Pectobacterium atrosepticum SCRI1043 encodes a single subtype I-F CRISPR system, which is composed of three CRISPR arrays and the cas operon encoding Cas1, Cas3 (a Cas2-Cas3 fusion), Csy1, Csy2, Csy3 and Cas6f (Csy4). The CRISPR arrays are transcribed into pre-crRNA (CRISPR RNA) and then processed by Cas6f to generate crRNAs. Furthermore, the formation of Cas protein complexes has been implicated in both the interference and acquisition stages of defence. In the present paper, we discuss the development of tightly controlled 'programmable' CRISPR arrays as tools to investigate CRISPR-Cas function and the effects of chromosomal targeting. Finally, we address how chromosomal targeting by CRISPR-Cas can cause large-scale genome deletions, which can ultimately influence bacterial evolution and pathogenicity.

  6. SemiSPECT: A small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays

    PubMed Central

    Kim, Hyunki; Furenlid, Lars R.; Crawford, Michael J.; Wilson, Donald W.; Barber, H. Bradford; Peterson, Todd E.; Hunter, William C. J.; Liu, Zhonglin; Woolfenden, James M.; Barrett, Harrison H.

    2008-01-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm × 2.7 cm × ~ 0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 × 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of −180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 × 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 × 10−4 with the energy window of ±10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT. PMID:16532954

  7. SemiSPECT: a small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays.

    PubMed

    Kim, Hyunki; Furenlid, Lars R; Crawford, Michael J; Wilson, Donald W; Barber, H Bradford; Peterson, Todd E; Hunter, William C J; Liu, Zhonglin; Woolfenden, James M; Barrett, Harrison H

    2006-02-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm x 2.7 cm x -0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 x 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of -180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 x 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 x 10(-4) with the energy window of +/-10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT.

  8. Performance evaluation of a novel high performance pinhole array detector module using NEMA NU-4 image quality phantom for four head SPECT Imaging

    NASA Astrophysics Data System (ADS)

    Rahman, Tasneem; Tahtali, Murat; Pickering, Mark R.

    2015-03-01

    Radiolabeled tracer distribution imaging of gamma rays using pinhole collimation is considered promising for small animal imaging. The recent availability of various radiolabeled tracers has enhanced the field of diagnostic study and is simultaneously creating demand for high resolution imaging devices. This paper presents analyses to represent the optimized parameters of a high performance pinhole array detector module using two different characteristics phantoms. Monte Carlo simulations using the Geant4 application for tomographic emission (GATE) were executed to assess the performance of a four head SPECT system incorporated with pinhole array collimators. The system is based on a pixelated array of NaI(Tl) crystals coupled to an array of position sensitive photomultiplier tubes (PSPMTs). The detector module was simulated to have 48 mm by 48 mm active area along with different pinhole apertures on a tungsten plate. The performance of this system has been evaluated using a uniform shape cylindrical water phantom along with NEMA NU-4 image quality (IQ) phantom filled with 99mTc labeled radiotracers. SPECT images were reconstructed where activity distribution is expected to be well visualized. This system offers the combination of an excellent intrinsic spatial resolution, good sensitivity and signal-to-noise ratio along with high detection efficiency over an energy range between 20-160 keV. Increasing number of heads in a stationary system configuration offers increased sensitivity at a spatial resolution similar to that obtained with the current SPECT system design with four heads.

  9. Quantification of maltol in Korean ginseng (Panax ginseng) products by high-performance liquid chromatography-diode array detector

    PubMed Central

    Jeong, Hyun Cheol; Hong, Hee-Do; Kim, Young-Chan; Rhee, Young Kyoung; Choi, Sang Yoon; Kim, Kyung-Tack; Kim, Sung Soo; Lee, Young-Chul; Cho, Chang-Won

    2015-01-01

    Background: Maltol, as a type of phenolic compounds, is produced by the browning reaction during the high-temperature treatment of ginseng. Thus, maltol can be used as a marker for the quality control of various ginseng products manufactured by high-temperature treatment including red ginseng. For the quantification of maltol in Korean ginseng products, an effective high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed. Materials and Methods: The HPLC-DAD method for maltol quantification coupled with a liquid-liquid extraction (LLE) method was developed and validated in terms of linearity, precision, and accuracy. An HPLC separation was performed on a C18 column. Results: The LLE methods and HPLC running conditions for maltol quantification were optimized. The calibration curve of the maltol exhibited good linearity (R2 = 1.00). The limit of detection value of maltol was 0.26 μg/mL, and the limit of quantification value was 0.79 μg/mL. The relative standard deviations (RSDs) of the data of the intra- and inter-day experiments were <1.27% and 0.61%, respectively. The results of the recovery test were 101.35–101.75% with an RSD value of 0.21–1.65%. The developed method was applied successfully to quantify the maltol in three ginseng products manufactured by different methods. Conclusion: The results of validation demonstrated that the proposed HPLC-DAD method was useful for the quantification of maltol in various ginseng products. PMID:26246746

  10. Determination of pesticides in sunflower seeds by high-performance liquid chromatography coupled with a diode array detector.

    PubMed

    Tuzimski, Tomasz; Rejczak, Tomasz

    2014-01-01

    The application of RP-HPLC with a diode array detector for identification and quantitative analysis of pesticides in sunflower seed samples is demonstrated. An HPLC procedure on C18 RP column has been developed for analysis of selected pesticides from different chemical groups: simazine, isoproturon, terbuthylazine, linuron, captan, terbutryn, procymidone, fenitrothion, clofentezine, and bromopropylate. We investigated the possibility of expanding the scope of the four analyte extraction procedures for isolation of pesticides from plant matrixes with high levels of lipids. The following procedures were tested: A, ultrasound-assisted solvent extraction (UAE) and SPE; B, dispersive-SPE (d-SPE); C, UAE and d-SPE; and D, UAE/SPE/d-SPE. Average recoveries from spiked samples at different concentrations in the range from 0.1 to 1.40 microg/g in the plant materials and the SDs for C18 cartridges and solvents by the proposed RP-HPLC-DAD method after the extraction procedures are also presented. The efficiency of procedures A-D was evaluated using real food samples from Hungary, Bulgaria, and Poland. The quantity of terbuthylazine determined was in the range of 7.1-12.7 ng/g (n = 6), whereas the quantity of procymidone determined was in the range of 3.7-5.7 ng/g (n = 3) in plant materials. The quantities of pesticides determined in sunflower seeds were below the maximum residue levels (excluding captan) established in the European Union legislation. The method was validated for precision and accuracy.

  11. A novel liquid chromatography method using diode-array detector for the determination of oleuropein in dietary supplements.

    PubMed

    Bertolini, Tiziana; Vicentini, Lorenza; Boschetti, Silvia; Andreatta, Paolo; Gatti, Rita

    2016-09-10

    A simple and fast chromatographic method using ultraviolet diode-array detector (UV-DAD) was developed for the automatic high performance liquid chromatography (HPLC) determination of the title of oleuropein in a new dietary supplements in form of effervescent granules. The chromatographic separations were performed on a C18 core-shell column with detection at λ=232nm. The mobile phase consisted of deionized water with 0.1% TFA and acetonitrile under gradient conditions at a flow-rate of 0.8mL/min. Oleuropein and oleuroside present in the raw material were characterized by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The validation of the analytical procedure has been performed determining the following parameters: specificity, linearity, repeatability, reproducibility, accuracy, limit of quantification (LOQ), stability of the standard and sample solutions. Linear response was observed in fortified placebo solutions (determination coefficient: 0.9998). Intra-day precision (relative standard deviation, RSD) was ≤5.0% for peak area and for retention times (tR) without significant differences between intra- and inter-day data. The limits of quantitation (LOQ) was about 5μg/mL and 9pmol/inject. Oleuropein recovery studies gave good results (99.9%) with a R.S.D. of 0.5%. The speed of analysis and the stability of the solutions with a fluctuation Δ (%) ≤2.0 at room temperature means an undoubted advantage of the method allowing the simultaneous preparation of many samples and consecutive chromatographic analyses by using an autosampler. The developed method is suitable for the quality control of oleuropein in raw material and industrial products. The method can be applied in any analytical laboratory not requiring a sophisticated instrumentation.

  12. SEARCH FOR GAMMA RAYS ABOVE 100 TeV FROM THE CRAB NEBULA WITH THE TIBET AIR SHOWER ARRAY AND THE 100 m{sup 2} MUON DETECTOR

    SciTech Connect

    Amenomori, M.; Bi, X. J.; Chen, W. Y.; Ding, L. K.; Feng, Zhaoyang; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, H. B.; Huang, J.; Chen, D.; Chen, T. L.; Danzengluobu; Hu, Haibing; Cui, S. W.; He, Z. T.; Feng, C. F.; Feng, Z. Y.; Hibino, K.; Hotta, N.; Collaboration: Tibet ASγ Collaboration; and others

    2015-11-10

    A 100 m{sup 2} muon detector (MD) was successfully constructed under the existing Tibet air shower (AS) array in the late fall of 2007. The sensitivity of the Tibet AS array to cosmic gamma rays can be improved by selecting muon-poor events with the MD. Our MC simulation of the MD response reasonably agrees with the experimental data in terms of the charge distribution for one-muon events and the background rejection power. Using the data collected by the Tibet AS array and the 100 m{sup 2} MD taken from 2008 March to 2010 February, we search for continuous gamma-ray emission from the Crab Nebula above ∼100 TeV. No significant excess is found, and the most stringent upper limit is obtained above 140 TeV.

  13. Improved performance of HgCdTe infrared detector focal plane arrays by modulating light field based on photonic crystal structure

    SciTech Connect

    Liang, Jian; Hu, Weida Ye, Zhenhua; Li, Zhifeng; Chen, Xiaoshuang Lu, Wei; Liao, Lei

    2014-05-14

    An HgCdTe long-wavelength infrared focal plane array photodetector is proposed by modulating light distributions based on the photonic crystal. It is shown that a promising prospect of improving performance is better light harvest and dark current limitation. To optimize the photon field distributions of the HgCdTe-based photonic crystal structure, a numerical method is built by combining the finite-element modeling and the finite-difference time-domain simulation. The optical and electrical characteristics of designed HgCdTe mid-wavelength and long-wavelength photon-trapping infrared detector focal plane arrays are obtained numerically. The results indicate that the photon crystal structure, which is entirely compatible with the large infrared focal plane arrays, can significantly reduce the dark current without degrading the quantum efficiency compared to the regular mesa or planar structure.

  14. Search for 100 TeV gamma rays from the Crab Nebula with the Tibet Air Shower Array and the 100 m2 muon detector

    NASA Astrophysics Data System (ADS)

    Sako, Takashi

    2016-07-01

    The 100 m ^{2} muon detector (MD) was constructed under the Tibet air shower (AS) array in the late autumn of 2007. By selecting muon-poor events with the MD, the sensitivity of the Tibet AS array to cosmic gamma rays can be improved. Our MC simulation of the MD response is in reasonable agreement with the experimental data, with regard to the charge distribution for one-muon events and the background rejection power. Using the data taken from 2008 March to 2010 February by the Tibet AS array and the 100 m ^{2} MD, we search for continuous 100 TeV gamma-ray emission from the Crab Nebula. No significant excess is detected, and the world's best upper limit is obtained above 140 TeV.

  15. Search for Gamma Rays above 100 TeV from the Crab Nebula with the Tibet Air Shower Array and the 100 m2 muon Detector

    NASA Astrophysics Data System (ADS)

    Amenomori, M.; Bi, X. J.; Chen, D.; Chen, T. L.; Chen, W. Y.; Cui, S. W.; Danzengluobu; Ding, L. K.; Feng, C. F.; Feng, Zhaoyang; Feng, Z. Y.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; He, Z. T.; Hibino, K.; Hotta, N.; Hu, Haibing; Hu, H. B.; Huang, J.; Jia, H. Y.; Jiang, L.; Kajino, F.; Kasahara, K.; Katayose, Y.; Kato, C.; Kawata, K.; Kozai, M.; Labaciren; Le, G. M.; Li, A. F.; Li, H. J.; Li, W. J.; Liu, C.; Liu, J. S.; Liu, M. Y.; Lu, H.; Meng, X. R.; Miyazaki, T.; Mizutani, K.; Munakata, K.; Nakajima, T.; Nakamura, Y.; Nanjo, H.; Nishizawa, M.; Niwa, T.; Ohnishi, M.; Ohta, I.; Ozawa, S.; Qian, X. L.; Qu, X. B.; Saito, T.; Saito, T. Y.; Sakata, M.; Sako, T. K.; Shao, J.; Shibata, M.; Shiomi, A.; Shirai, T.; Sugimoto, H.; Takita, M.; Tan, Y. H.; Tateyama, N.; Torii, S.; Tsuchiya, H.; Udo, S.; Wang, H.; Wu, H. R.; Xue, L.; Yamamoto, Y.; Yamauchi, K.; Yang, Z.; Yasue, S.; Yuan, A. F.; Yuda, T.; Zhai, L. M.; Zhang, H. M.; Zhang, J. L.; Zhang, X. Y.; Zhang, Y.; Zhang, Yi; Zhang, Ying; Zhaxisangzhu; Zhou, X. X.; Tibet ASγ Collaboration

    2015-11-01

    A 100 m2 muon detector (MD) was successfully constructed under the existing Tibet air shower (AS) array in the late fall of 2007. The sensitivity of the Tibet AS array to cosmic gamma rays can be improved by selecting muon-poor events with the MD. Our MC simulation of the MD response reasonably agrees with the experimental data in terms of the charge distribution for one-muon events and the background rejection power. Using the data collected by the Tibet AS array and the 100 m2 MD taken from 2008 March to 2010 February, we search for continuous gamma-ray emission from the Crab Nebula above ˜100 TeV. No significant excess is found, and the most stringent upper limit is obtained above 140 TeV.

  16. Feasibility study of an orbiting laboratory for testing CSI technology

    NASA Technical Reports Server (NTRS)

    Bicos, Andrew S.; Loboda, Gregory G.

    1993-01-01

    A concept for an orbiting laboratory for testing Controls-Structures Integration (CSI) technology is described. The CSI-Star concept reflects a lower cost, higher risk approach. The concept supports demonstration and validation testing for critical CSI technologies at a cost of $20M to $26M with a 1-year reliability of approximately 0.9. The Ball Aerospace QuickStar bus is the carrier for the CSI test article. QuickStar is launched as a secondary payload on the McDonnell Douglas Delta 2. The QuickStar/Delta 2 approach is flight proven. The CSI test article is a 20 foot, 1 Hz, truss beam which is deployed from the QuickStar bus. The test article is well instrumented for quality system identification. The laboratory provides three layers of active control consisting of global vibration suppression along the truss beam, vibration isolation between the beam and instrument platforms, and vibration compensation through the use of gimbaled platforms which point lasers relative to optical sensor targets. The configuration simulates the dynamics of multi-instrument science platforms such as those of the Earth Observation System (EOS) while maintaining strong ties to astrophysics missions such as the Optical Interferometer. Uplink/downlink services and a reprogrammable computer provide flexibility for long-term investigations by members of the CSI community (NASA, DoD, academia, and industry). CSI-Star fills the gap between short-term experiments, which have been conducted primarily on the Shuttle, and future science missions which require the technology. The on-orbit maturity of CSI technology must be established to obtain acceptance by project managers and to promote injection of the technology into future science missions.

  17. Feasibility study of an orbiting laboratory for testing CSI technology

    NASA Astrophysics Data System (ADS)

    Bicos, Andrew S.; Loboda, Gregory G.

    1993-08-01

    A concept for an orbiting laboratory for testing Controls-Structures Integration (CSI) technology is described. The CSI-Star concept reflects a lower cost, higher risk approach. The concept supports demonstration and validation testing for critical CSI technologies at a cost of $20M to $26M with a 1-year reliability of approximately 0.9. The Ball Aerospace QuickStar bus is the carrier for the CSI test article. QuickStar is launched as a secondary payload on the McDonnell Douglas Delta 2. The QuickStar/Delta 2 approach is flight proven. The CSI test article is a 20 foot, 1 Hz, truss beam which is deployed from the QuickStar bus. The test article is well instrumented for quality system identification. The laboratory provides three layers of active control consisting of global vibration suppression along the truss beam, vibration isolation between the beam and instrument platforms, and vibration compensation through the use of gimbaled platforms which point lasers relative to optical sensor targets. The configuration simulates the dynamics of multi-instrument science platforms such as those of the Earth Observation System (EOS) while maintaining strong ties to astrophysics missions such as the Optical Interferometer. Uplink/downlink services and a reprogrammable computer provide flexibility for long-term investigations by members of the CSI community (NASA, DoD, academia, and industry). CSI-Star fills the gap between short-term experiments, which have been conducted primarily on the Shuttle, and future science missions which require the technology. The on-orbit maturity of CSI technology must be established to obtain acceptance by project managers and to promote injection of the technology into future science missions.

  18. Development of a cryogenic radiation detector for mapping radio frequency superconducting cavity field emissions

    SciTech Connect

    Danny Dotson; John Mammosser

    2005-05-01

    Field emissions in a super conducting helium cooled RF cavity and the production of radiation (mostly X-Rays) have been measured externally on cryomodules at Jefferson Lab since 1991. External measurements are limited to radiation energies above 100 keV due to shielding of the stainless steel cryogenic body. To measure the onset of and to map field emissions from a superconducting cavity requires the detecting instrument be inside the shield and within the liquid Helium. Two possible measurement systems are undergoing testing at JLab. A CsI detector array set on photodiodes and an X-Ray film camera with a fixed aperture. Several devices were tested in the cell with liquid Helium without success. The lone survivor, a CsI array, worked but saturated at high power levels due to backscatter. The array was encased in a lead shield with a slit opening set to measure the radiation emitted directly from the cell eliminating a large portion of the backscatter. This is a work in progress and te sting should be complete before the PAC 05. The second system being tested is passive. It is a shielded box with an aperture to expose radiation diagnostic film located inside to direct radiation from the cell. Developing a technique for mapping field emissions in cryogenic cells will assist scientists and engineers in pinpointing any surface imperfections for examination.

  19. Photon detectors

    SciTech Connect

    Va`vra, J.

    1995-10-01

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF{sub 2} windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission.

  20. Fast CsI-phoswich detector

    DOEpatents

    Langenbrunner, J.R.

    1996-05-07

    An improved phoswich radiation detector used pure CsI crystal and a fast plastic scintillator and a single photomultiplier tube. The plastic is arranged to receive incident radiation, and that which passed through then strikes the CsI crystal. Scintillation light from both the plastic and CsI crystal are applied to the photomultiplier tube, with the light from the plastic passing through the crystal without absorption therein. Electronics are provided for analyzing the output of the photomultiplier tube to discriminate responses due to the plastic and the CsI crystal, through short gate and long gate integration, to produce results which are indicative of the characteristics of the different types of incident radiation, even in the presence of large amounts of radiation. The phoswich detector has excellent timing resolution. The scintillators of the CsI- phoswich were chosen for their fast risetimes, of about 3 ns for NE102A, and 30 ns for the pure CsI. 5 figs.

  1. Fast CsI-phoswich detector

    DOEpatents

    Langenbrunner, James R.

    1996-01-01

    An improved phoswich radiation detector used pure CsI crystal and a fast plastic scintillator and a single photomultiplier tube. The plastic is arranged to receive incident radiation, and that which passed through then strikes the CsI crystal. Scintillation light from both the plastic and CsI crystal are applied to the photomultiplier tube, with the light from the plastic passing through the crystal without absorption therein. Electronics are provided for analyzing the output of the photomultiplier tube to discriminate responses due to the plastic and the CsI crystal, through short gate and long gate integration, to produce results which are indicative of the characteristics of the different types of incident radiation, even in the presence of large amounts of radiation. The phoswich detector has excellent timing resolution. The scintillators of the CsI- phoswich were chosen for their fast risetimes, of about 3 ns for NE102A, and 30 ns for the pure CsI.

  2. 16-element photodiode array for the angular microdeflection detector and for stabilization of a laser radiation direction

    NASA Astrophysics Data System (ADS)

    Wegrzecki, Maciej; Piotrowski, Tadeusz; Bar, Jan; Dobrowolski, Rafał; Klimov, Andrii; Klos, Helena; Marchewka, Michał; Nieprzecki, Marek; Panas, Andrzej; Prokaryn, Piotr; Seredyński, Bartłomiej; Sierakowski, Andrzej; Słysz, Wojciech; Szmigiel, Dariusz; Zaborowski, Michal

    2016-12-01

    In this paper, the design and technology of two types of 16-element photodiode arrays is described. The arrays were developed by the ITE and are to be used in detection of microdeflection of laser radiation at the Institute of Metrology and Biomedical Engineering in the Faculty of Mechatronics of Warsaw University of Technology. The electrical and photoelectrical parameters of the arrays are presented.

  3. Multispectral Detector Array Technology

    NASA Astrophysics Data System (ADS)

    Jokerst, Nan M.

    1999-12-01

    A sensor is a device used to sense or measure physical phenomena. Thus, sensors may detect electrical, mechanical, optical, chemical, tactile, or acoustic signatures of an object or scene. Objects that may be difficult to discriminate using a single sensor are often differentiated with a multiple sensor system that exploits several signature phenomena. The application of multiple sensors (and the fusion of their data) offers numerous potential performance benefits over traditional single sensor approaches. In our application, which is infrared target discrimination, employing multiple sensors, which respond to different signatures, increases the probability that a target signature will be found against a given set of weather, clutter or background noise sources. A multiple sensor system, in other words, diminishes ambiguity and uncertainty in the measured information by reducing the set of hypotheses about the target or event. Multiple sensors may also be used to reduce the vulnerability to false conclusions drawn from data of a single sensor. For instance, missiles may carry multiple sensors to better guarantee a hit or a radar can use multiple sensors to counter-jam incoming missiles.

  4. Csy4 is responsible for CRISPR RNA processing in Pectobacterium atrosepticum.

    PubMed

    Przybilski, Rita; Richter, Corinna; Gristwood, Tamzin; Clulow, James S; Vercoe, Reuben B; Fineran, Peter C

    2011-01-01

    CRISPR/Cas systems provide bacteria and archaea with small RNA-based adaptive immunity against foreign elements such as phages and plasmids. An important step in the resistance mechanism involves the generation of small guide RNAs (crRNAs) that, in combination with Cas proteins, recognize and inhibit foreign nucleic acids in a sequence specific manner. The generation of crRNAs requires processing of the primary CRISPR RNA by an endoribonuclease. In this study we have characterized the Ypest subtype CRISPR/Cas system in the plant pathogen Pectobacterium atrosepticum. We analyse the transcription of the cas genes and the 3 CRISPR arrays. The cas genes are expressed as an operon and all three CRISPR arrays are transcribed and processed into small RNAs. The Csy4 protein was identified as responsible for processing of CRISPR RNA in vivo and in vitro into crRNAs and appears to interact with itself in the absence of other Cas proteins. This study furthers our understanding of the CRISPR/Cas mechanism by providing the first in vivo evidence that the CRISPR endoribonuclease Csy4 generates crRNAs in its native host and characterizes the operonic transcription of the cas cluster.

  5. Characterization of CdTe sensors with Schottky contacts coupled to charge-integrating pixel array detectors for X-ray science

    NASA Astrophysics Data System (ADS)

    Becker, J.; Tate, M. W.; Shanks, K. S.; Philipp, H. T.; Weiss, J. T.; Purohit, P.; Chamberlain, D.; Ruff, J. P. C.; Gruner, S. M.

    2016-12-01

    Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we present characterizations of CdTe sensors hybridized with two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods < 150 ns. The second detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both detector chips consist of a 128 × 128 pixel array with (150 μm)2 pixels.

  6. Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants Dimethylmethylphosphonate and Diisopropy

    NASA Astrophysics Data System (ADS)

    Hopkins, Alan R.; Lewis, Nathan S.

    2002-06-01

    Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black-organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m-3. These values are lower than the EC50 value for the nerve agents sarin (methylphosphonofluoridic acid, (1-methylethyl) ester) and soman, which have been established as equals 0.8 mg m-3. Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes in a laboratory air background. In addition, DMMP at 27 mg m-3 could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferents in the background ambient, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected.

  7. Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants dimethylmethylphosphonate and diisopropylmethylphosponate.

    PubMed

    Hopkins, A R; Lewis, N S

    2001-03-01

    Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black/ organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m(-3). These values are lower than the EC50 value (where EC50 is the airborne concentration sufficient to induce severe effects in 50% of those exposed for 30 min) for the nerve agents sarin (methylphosphonofluoridic acid, 1-methylethyl ester) and soman (methylphosphonofluoridic acid, 1,2,2-trimethylpropyl ester), which has been established as approximately 0.8 mg m(-3). Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes (including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran) in a laboratory air background. In addition, DMMP at 27 mg m(-3) could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferences, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected.

  8. X-ray tests of a Pixel Array Detector for coherent x-ray imaging at the Linac Coherent Light Source

    NASA Astrophysics Data System (ADS)

    Koerner, L. J.; Philipp, H. T.; Hromalik, M. S.; Tate, M. W.; Gruner, S. M.

    2009-03-01

    Test results are presented of a pixel array detector (PAD) developed for x-ray imaging at the Stanford Linear Coherent Light Source (LCLS). The basic module of the PAD consists of two bump-bonded chips: a reverse-biased silicon diode chip of 185 × 194 pixels, each of which is coupled by bump-bonds to a charge integrating CMOS ASIC with digitization in each pixel. The LCLS experiment requires a high signal-to-noise ratio for detection of single 8 keV x-rays, a pixel full-well exceeding 1,000 8 keV x-rays, a frame-rate of 120 Hz, and the ability to handle the arrival of thousands of x-rays per pixel in tens of femtoseconds. Measurements have verified a pixel full-well value of 2,700 8 keV x-rays. Single 8 keV photon detection has been shown with a signal-to-noise ratio of >6. Line-spread response measurements confirmed charge spreading to be limited to nearest neighbor pixels. Modules still functioned after dosages up to 75 Mrad(Si) at the detector face. Work is proceeding to incorporate an array of modules into a large-area detector.

  9. Discovery of SiCSi in IRC +10216: A missing link between gas and dust carriers of Si-C bonds.

    PubMed

    Cernicharo, J; McCarthy, M C; Gottlieb, C A; Agúndez, M; Velilla Prieto, L; Baraban, J H; Changala, P B; Guélin, M; Kahane, C; Martin-Drumel, M A; Patel, N A; Reilly, N J; Stanton, J F; Quintana-Lacaci, G; Thorwirth, S; Young, K H

    2015-06-10

    We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array, the bulk of the SiCSi emission arises from a region of 6″ in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the most abundant species harboring a Si-C bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains.

  10. Discovery of SiCSi in IRC +10216: A missing link between gas and dust carriers of Si–C bonds

    PubMed Central

    Cernicharo, J.; McCarthy, M. C.; Gottlieb, C. A.; Agúndez, M.; Velilla Prieto, L.; Baraban, J. H.; Changala, P. B.; Guélin, M.; Kahane, C.; Martin-Drumel, M. A.; Patel, N. A.; Reilly, N. J.; Stanton, J. F.; Quintana-Lacaci, G.; Thorwirth, S.; Young, K. H.

    2015-01-01

    We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM10 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array11, the bulk of the SiCSi emission arises from a region of 6″ in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the most abundant species harboring a Si–C bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains. PMID:26722621

  11. MagicPlate-512: A 2D silicon detector array for quality assurance of stereotactic motion adaptive radiotherapy

    SciTech Connect

    Petasecca, M. Newall, M. K.; Aldosari, A. H.; Fuduli, I.; Espinoza, A. A.; Porumb, C. S.; Guatelli, S.; Metcalfe, P.; Lerch, M. L. F.; Rosenfeld, A. B.; Booth, J. T.; Colvill, E.; Duncan, M.; Cammarano, D.; Carolan, M.; Oborn, B.; Perevertaylo, V.; Keall, P. J.

    2015-06-15

    Purpose: Spatial and temporal resolutions are two of the most important features for quality assurance instrumentation of motion adaptive radiotherapy modalities. The goal of this work is to characterize the performance of the 2D high spatial resolution monolithic silicon diode array named “MagicPlate-512” for quality assurance of stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) combined with a dynamic multileaf collimator (MLC) tracking technique for motion compensation. Methods: MagicPlate-512 is used in combination with the movable platform HexaMotion and a research version of radiofrequency tracking system Calypso driving MLC tracking software. The authors reconstruct 2D dose distributions of small field square beams in three modalities: in static conditions, mimicking the temporal movement pattern of a lung tumor and tracking the moving target while the MLC compensates almost instantaneously for the tumor displacement. Use of Calypso in combination with MagicPlate-512 requires a proper radiofrequency interference shielding. Impact of the shielding on dosimetry has been simulated by GEANT4 and verified experimentally. Temporal and spatial resolutions of the dosimetry system allow also for accurate verification of segments of complex stereotactic radiotherapy plans with identification of the instant and location where a certain dose is delivered. This feature allows for retrospective temporal reconstruction of the delivery process and easy identification of error in the tracking or the multileaf collimator driving systems. A sliding MLC wedge combined with the lung motion pattern has been measured. The ability of the MagicPlate-512 (MP512) in 2D dose mapping in all three modes of operation was benchmarked by EBT3 film. Results: Full width at half maximum and penumbra of the moving and stationary dose profiles measured by EBT3 film and MagicPlate-512 confirm that motion has a significant impact on the dose distribution. Motion

  12. MT6415CA: a 640×512-15µm CTIA ROIC for SWIR InGaAs detector arrays

    NASA Astrophysics Data System (ADS)

    Eminoglu, Selim; Isikhan, Murat; Bayhan, Nusret; Gulden, M. Ali; Incedere, O. Samet; Soyer, S. Tuncer; Kocak, Serhat; Yilmaz, Gokhan S.; Akin, Tayfun

    2013-06-01

    This paper reports the development of a new low-noise CTIA ROIC (MT6415CA) suitable for SWIR InGaAs detector arrays for low-light imaging applications. MT6415CA is the second product in the MT6400 series ROICs from Mikro-Tasarim Ltd., which is a fabless IC design house specialized in the development of monolithic imaging sensors and ROICs for hybrid imaging sensors. MT6415CA is a low-noise snapshot CTIA ROIC, has a format of 640 × 512 and pixel pitch of 15 µm, and has been developed with the system-on-chip architecture in mind, where all the timing and biasing for this ROIC are generated on-chip without requiring any external inputs. MT6415CA is a highly configurable ROIC, where many of its features can be programmed through a 3-wire serial interface allowing on-the-fly configuration of many ROIC features. It performs snapshot operation both using Integrate-Then-Read (ITR) and Integrate-While-Read (IWR) modes. The CTIA type pixel input circuitry has three gain modes with programmable full-well-capacity (FWC) values of 10.000 e-, 20.000 e-, and 350.000 e- in the very high gain (VHG), high-gain (HG), and low-gain (LG) modes, respectively. MT6415CA has an input referred noise level of less than 5 e- in the very high gain (VHG) mode, suitable for very low-noise SWIR imaging applications. MT6415CA has 8 analog video outputs that can be programmed in 8, 4, or 2-output modes with a selectable analog reference for pseudo-differential operation. The ROIC runs at 10 MHz and supports frame rate values up to 200 fps in the 8-output mode. The integration time can be programmed up to 1s in steps of 0.1 µs. The ROIC uses 3.3 V and 1.8V supply voltages and dissipates less than 150 mW in the 4-output mode. MT6415CA is fabricated using a modern mixed-signal CMOS process on 200 mm CMOS wafers, and tested parts are available at wafer or die levels with test reports and wafer maps. A compact USB 3.0 camera and imaging software have been developed to demonstrate the imaging

  13. X-ray detectors in medical imaging

    NASA Astrophysics Data System (ADS)

    Spahn, Martin

    2013-12-01

    Healthcare systems are subject to continuous adaptation, following trends such as the change of demographic structures, the rise of life-style related and chronic diseases, and the need for efficient and outcome-oriented procedures. This also influences the design of new imaging systems as well as their components. The applications of X-ray imaging in the medical field are manifold and have led to dedicated modalities supporting specific imaging requirements, for example in computed tomography (CT), radiography, angiography, surgery or mammography, delivering projection or volumetric imaging data. Depending on the clinical needs, some X-ray systems enable diagnostic imaging while others support interventional procedures. X-ray detector design requirements for the different medical applications can vary strongly with respect to size and shape, spatial resolution, frame rates and X-ray flux, among others. Today, integrating X-ray detectors are in common use. They are predominantly based on scintillators (e.g. CsI or Gd2O2S) and arrays of photodiodes made from crystalline silicon (Si) or amorphous silicon (a-Si) or they employ semiconductors (e.g. Se) with active a-Si readout matrices. Ongoing and future developments of X-ray detectors will include optimization of current state-of-the-art integrating detectors in terms of performance and cost, will enable the usage of large size CMOS-based detectors, and may facilitate photon counting techniques with the potential to further enhance performance characteristics and foster the prospect of new clinical applications.

  14. Natural Linewidth Chemical Shift Imaging (NL-CSI)

    PubMed Central

    Bashir, Adil; Yablonskiy, Dmitriy A.

    2007-01-01

    The discrete Fourier transform (FT) is a conventional method for spatial reconstruction of chemical shifting imaging (CSI) data. Due to point spread function (PSF) effects, FT reconstruction leads to intervoxel signal leakage (Gibbs ringing). Spectral localization by imaging (SLIM) reconstruction was previously proposed to overcome this intervoxel signal contamination. However, the existence of magnetic field inhomogeneities creates an additional source of intervoxel signal leakage. It is demonstrated herein that even small field inhomogeneities substantially amplify intervoxel signal leakage in both FT and SLIM reconstruction approaches. A new CSI data acquisition strategy and reconstruction algorithm (natural linewidth (NL) CSI) is presented that eliminates effects of magnetic field inhomogeneity-induced intervoxel signal leakage and intravoxel phase dispersion on acquired data. The approach is based on acquired CSI data, high-resolution images, and magnetic field maps. The data are reconstructed based on the imaged object structure (as in the SLIM approach) and a reconstruction matrix that takes into account the inhomogeneous field distribution inside anatomically homogeneous compartments. Phantom and in vivo results show that the new method allows field inhomogeneity effects from the acquired MR signal to be removed so that the signal decay is determined only by the “natural”R2 relaxation rate constant (hence the term “natural linewidth” CSI). PMID:16721752

  15. Fast Padé Transform Accelerated CSI for Hyperpolarized MRS

    PubMed Central

    Hansen, Esben Szocska Søvsø; Kim, Sun; Miller, Jack J.; Geferath, Marcus; Morrell, Glen; Laustsen, Christoffer

    2016-01-01

    The fast Padé transform (FPT) is a method of spectral analysis that can be used to reconstruct nuclear magnetic resonance spectra from truncated free induction decay signals with superior robustness and spectral resolution compared with conventional Fourier analysis. The aim of this study is to show the utility of FPT in reducing of the scan time required for hyperpolarized 13C chemical shift imaging (CSI) without sacrificing the ability to resolve a full spectrum. Simulations, phantom, and in vivo hyperpolarized [1-13C] pyruvate CSI data were processed with FPT and compared with conventional analysis methods. FPT shows improved stability and spectral resolution on truncated data compared with the fast Fourier transform and shows results that are comparable to those of the model-based fitting methods, enabling a reduction in the needed acquisition time in 13C CSI experiments. Using FPT can reduce the readout length in the spectral dimension by 2–6 times in 13C CSI compared with conventional Fourier analysis without sacrificing the spectral resolution. This increased speed is crucial for 13C CSI because T1 relaxation considerably limits the available scan time. In addition, FPT can also yield direct quantification of metabolite concentration without the additional peak analysis required in conventional Fourier analysis. PMID:28018967

  16. Commissioning of the NPDGamma Detector Array: Counting Statistics in Current Mode Operation and Parity Violation in the Capture of Cold Neutrons on B 4 C and (27) Al.

    PubMed

    Gericke, M T; Bowman, J D; Carlini, R D; Chupp, T E; Coulter, K P; Dabaghyan, M; Desai, D; Freedman, S J; Gentile, T R; Gillis, R C; Greene, G L; Hersman, F W; Ino, T; Ishimoto, S; Jones, G L; Lauss, B; Leuschner, M B; Losowski, B; Mahurin, R; Masuda, Y; Mitchell, G S; Muto, S; Nann, H; Page, S A; Penttila, S I; Ramsay, W D; Santra, S; Seo, P-N; Sharapov, E I; Smith, T B; Snow, W M; Wilburn, W S; Yuan, V; Zhu, H

    2005-01-01

    The NPDGamma γ-ray detector has been built to measure, with high accuracy, the size of the small parity-violating asymmetry in the angular distribution of gamma rays from the capture of polarized cold neutrons by protons. The high cold neutron flux at the Los Alamos Neutron Scattering Center (LANSCE) spallation neutron source and control of systematic errors require the use of current mode detection with vacuum photodiodes and low-noise solid-state preamplifiers. We show that the detector array operates at counting statistics and that the asymmetries due to B4C and (27)Al are zero to with- in 2 × 10(-6) and 7 × 10(-7), respectively. Boron and aluminum are used throughout the experiment. The results presented here are preliminary.

  17. Image acquisition, geometric correction and display of images from a 2×2 x-ray detector array based on Electron Multiplying Charge Coupled Device (EMCCD) technology.

    PubMed

    Vasan, S N Swetadri; Sharma, P; Ionita, Ciprian N; Titus, A H; Cartwright, A N; Bednarek, D R; Rudin, S

    2013-03-06

    A high resolution (up to 11.2 lp/mm) x-ray detector with larger field of view (8.5 cm × 8.5 cm) has been developed. The detector is a 2 × 2 array of individual imaging modules based on EMCCD technology. Each module outputs a frame of size 1088 × 1037 pixels, each 12 bits. The frames from the 4 modules are acquired into the processing computer using one of two techniques. The first uses 2 CameraLink communication channels with each carrying information from two modules, the second uses a application specific custom integrated circuits, the Multiple Module Multiplexer Integrated Circuit (MMMIC), 3 of which are used to multiplex the data from 4 modules into one CameraLink channel. Once the data is acquired using either of the above mentioned techniques, it is decoded in the graphics processing unit (GPU) to form one single frame of size 2176 × 2074 pixels each 16 bits. Each imaging module uses a fiber optic taper coupled to the EMCCD sensor. To correct for mechanical misalignment between the sensors and the fiber optic tapers and produce a single seamless image, the images in each module may be rotated and translated slightly in the x-y plane with respect to each other. To evaluate the detector acquisition and correction techniques, an aneurysm model was placed over an anthropomorphic head phantom and a coil was guided into the aneurysm under fluoroscopic guidance using the detector array. Image sequences before and after correction are presented which show near-seamless boundary matching and are well suited for fluoroscopic imaging.

  18. Masking mechanisms applied to thin-film coatings for the manufacturing of linear variable filters for two-dimensional array detectors.

    PubMed

    Abel-Tibérini, Laëtitia; Lemarquis, Frédéric; Lequime, Michel

    2008-10-20

    We propose a method for manufacturing linear variable interference filters for two-dimensional (2D) array detectors, based on the use of correcting masks combining both rotation and translation movements of the masks and substrates. The major advantage of this method is its capability to produce several identical filters in a single run. 20 mm x 20 mm samples were manufactured with a wavelength ratio almost equal to 2 along the thickness gradient direction. In agreement with calculations, the measured uniformity perpendicular to the gradient is about 99.8% along 20 mm.

  19. A Comparison of DEF X-Ray Film and a Photodiode Array (Reticon) as Detectors for an X-Ray Crystal Spectrometer.

    PubMed

    Goodman, D A; Eason, R W; Shiwai, B; Allinson, N; Magorrian, B; Grande, M; Ridgley, A

    1989-01-01

    A crystal spectrometer with a photodiode array (PDA) detector was tested for a range of x-ray energies between 1 and 2 keV. A laser-produced plasma has been used as an x-ray source and was generated by the high-power (Vulcan) glass laser system at the SERC Rutherford Appleton Laboratory, UK. The performance of the array was directly compared with the response of Kodak DEF x-ray film. In order to compare quantitatively the performances of the PDA and the film, detective quantum efficiency (DQE) considerations are presented for both devices. It is demonstrated that the PDA has a useful dynamic range which is approximately seven times greater than that of film, a peak DQE of approximately six times that of film, and a greatly superior low-signal performance. The operational characteristics of the PDA are discussed.

  20. SU-E-T-644: Evaluation of Angular Dependence Correction for 2D Array Detector Using for Quality Assurance of Volumetric Modulated Arc Therapy

    SciTech Connect

    Karthikeyan, N; Ganesh, K M; Vikraman, S; Shariff, MH

    2014-06-15

    Purpose: To evaluate the angular dependence correction for Matrix Evolution 2D array detector in quality assurance of volumetric modulated arc therapy(VMAT). Methods: Total ten patients comprising of different sites were planned for VMAT and taken for the study. Each plan was exposed on Matrix Evolution 2D array detector with Omnipro IMRT software based on the following three different methods using 6MV photon beams from Elekta Synergy linear accelerator. First method, VMAT plan was delivered on Matrix Evolution detector as it gantry mounted with dedicated holder with build-up of 2.3cm. Second, the VMAT plan was delivered with the static gantry angle on to the table mounted setup. Third, the VMAT plan was delivered with actual gantry angle on Matrix Evolution detector fixed in Multicube phantom with gantry angle sensor and angular dependence correction were applied to quantify the plan quality. For all these methods, the corresponding QA plans were generated in TPS and the dose verification was done for both point and 2D fluence analysis with pass criteria of 3% dose difference and 3mm distance to agreement. Results: The measured point dose variation for the first method was observed as 1.58±0.6% of mean and SD with TPS calculated. For second and third method, the mean and standard deviation(SD) was observed as 1.67±0.7% and 1.85±0.8% respectively. The 2D fluence analysis of measured and TPS calculated has the mean and SD of 97.9±1.1%, 97.88±1.2% and 97.55±1.3% for first, second and third methods respectively. The calculated two-tailed Pvalue for point dose and 2D fluence analysis shows the insignificance with values of 0.9316 and 0.9015 respectively, among the different methods of QA. Conclusion: The qualitative evaluation of angular dependence correction for Matrix Evolution 2D array detector shows its competency in accuracy of quality assurance measurement of composite dose distribution of volumetric modulated arc therapy.

  1. MAD-4-MITO, a multi array of detectors for ground-based mm/submm SZ observations

    NASA Astrophysics Data System (ADS)

    Lamagna, L.; de Petris, M.; Melchiorri, F.; Battistelli, E.; de Grazia, M.; Luzzi, G.; Orlando, A.; Savini, G.

    2002-05-01

    The last few years have seen a large development of mm technology and ultra-sensitive detectors devoted to microwave astronomy and astrophysics. The possibility to deal with large numbers of these detectors assembled into multi-pixel imaging systems has greatly improved the performance of microwave observations, even from ground-based stations, especially combining the power of multi-band detectors with their new imaging capabilities. Hereafter, we will present the development of a multi-pixel solution devoted to Sunyaev-Zel'dovich observations from ground-based telescopes, that is going to be operated from the Millimeter and Infrared Testagrigia Observatory. .

  2. Cadmium mercury telluride infrared detectors

    NASA Astrophysics Data System (ADS)

    Elliott, C. T.

    Signal Processing In The Element (SPITE) detectors used in high performance thermal imaging systems are discussed. Developments to improve spatial and temperature resolution are outlined. Focal plane arrays of electronically scanned two-dimensional arrays of CMT detectors are treated. Use of photovoltaic CMT detectors hybridized with silicon addressing circuits is reported. Research to raise the operating temperature of infrared detectors is summarized.

  3. Photodiode array to charged aerosol detector response ratio enables comprehensive quantitative monitoring of basic drugs in blood by ultra-high performance liquid chromatography.

    PubMed

    Viinamäki, Jenni; Ojanperä, Ilkka

    2015-03-20

    Quantitative screening for a broad range of drugs in blood is regularly required to assess drug abuse and poisoning within analytical toxicology. Mass spectrometry-based procedures suffer from the large amount of work required to maintain quantitative calibration in extensive multi-compound methods. In this study, a quantitative drug screening method for blood samples was developed based on ultra-high performance liquid chromatography with two consecutive detectors: a photodiode array detector and a corona charged aerosol detector (UHPLC-DAD-CAD). The 2.1 mm × 150 mm UHPLC column contained a high-strength silica C18 bonded phase material with a particle size of 1.8 μm, and the mobile phase consisted of methanol/0.1% trifluoroacetic acid in gradient mode. Identification was based on retention time, UV spectrum and the response ratio from the two detectors. Using historic calibration over a one-month period, the median precision (RSD) of retention times was 0.04% and the median accuracy (bias) of quantification 6.75%. The median precision of the detector response ratio over two orders of magnitude was 12%. The applicable linear ranges were generally 0.05-5 mg L(-1). The method was validated for 161 compounds, including antipsychotics, antidepressants, antihistamines, opioid analgesics, and adrenergic beta blocking drugs, among others. The main novelty of the method was the proven utility of the response ratio of DAD to CAD, which provided the additional identification efficiency required. Unlike with mass spectrometry, the high stability of identification and quantification allowed the use of facile historic calibration.

  4. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras.

    PubMed

    Bolotnikov, A E; Ackley, K; Camarda, G S; Cherches, C; Cui, Y; De Geronimo, G; Fried, J; Hodges, D; Hossain, A; Lee, W; Mahler, G; Maritato, M; Petryk, M; Roy, U; Salwen, C; Vernon, E; Yang, G; James, R B

    2015-07-01

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  5. Quality evaluation of Radix Stemonae through simultaneous quantification of bioactive alkaloids by high-performance liquid chromatography coupled with diode array and evaporative light scattering detectors.

    PubMed

    Li, Song-Lin; Jiang, Ren-Wang; Hon, Po-Ming; Cheng, Ling; Xu, Hong-Xi; Greger, Harald; But, Paul Pui-Hay; Shaw, Pang-Chui

    2007-10-01

    A high-performance liquid chromatography coupled with diode array detection and evaporative light scattering detection (HPLC-DAD-ELSD) method was developed to simultaneously quantify six major bioactive alkaloids belonging to different structure types in Radix Stemonae, Bai-Bu in Chinese, a traditionally used antitussive and insecticidal medicinal material in China and other countries of Southeast Asia. Diode array detector (DAD) with the wavelengths at 307 and 260 nm was used to monitor the conjugated system of protostemonine (2) and maistemonine (4), respectively, whereas evaporative light scattering detector (ELSD) was employed to detect croomine (1), stemoninine (3), neotuberostemonine (5) and tuberostemonine (6), the other four analytes with no or poor chromophores. The assay was validated to be sensitive, precise and accurate, with a detection limit of 3.64-0.04 microg/mL depending on the individual analytes. The overall intra- and inter-day variations were less than 9.3%, and the overall recoveries higher than 91.2%, respectively. The correlation coefficients of the calibration curves were better than 0.996 for all analytes. The newly established method was successfully utilized to determine six major components in the genuine sources of Radix Stemonae: Stemona japonica, S. sessilifolia and S. tuberosa. Significant variations of contents of these components were demonstrated in samples of these three species. This simple, rapid, low-cost and reliable method is suitable for the routine quality control of herbal medicines containing bioactive components with different structure types such as Radix Stemonae.

  6. A SiPM-based isotropic-3D PET detector X'tal cube with a three-dimensional array of 1 mm(3) crystals.

    PubMed

    Yamaya, Taiga; Mitsuhashi, Takayuki; Matsumoto, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Kawai, Hideyuki; Suga, Mikio; Watanabe, Mitsuo

    2011-11-07

    We are developing a novel, general purpose isotropic-3D PET detector X'tal cube which has high spatial resolution in all three dimensions. The research challenge for this detector is implementing effective detection of scintillation photons by covering six faces of a segmented crystal block with silicon photomultipliers (SiPMs). In this paper, we developed the second prototype of the X'tal cube for a proof-of-concept. We aimed at realizing an ultimate detector with 1.0 mm(3) cubic crystals, in contrast to our previous development using 3.0 mm(3) cubic crystals. The crystal block was composed of a 16 × 16 × 16 array of lutetium gadolinium oxyorthosilicate (LGSO) crystals 0.993 × 0.993 × 0.993 mm(3) in size. The crystals were optically glued together without inserting any reflector inside and 96 multi-pixel photon counters (MPPCs, S10931-50P, i.e. six faces each with a 4 × 4 array of MPPCs), each having a sensitive area of 3.0 × 3.0 mm(2), were optically coupled to the surfaces of the crystal block. Almost all 4096 crystals were identified through Anger-type calculation due to the finely adjusted reflector sheets inserted between the crystal block and light guides. The reflector sheets, which formed a belt of 0.5 mm width, were placed to cover half of the crystals of the second rows from the edges in order to improve identification performance of the crystals near the edges. Energy resolution of 12.7% was obtained at 511 keV with almost uniform light output for all crystal segments thanks to the effective detection of the scintillation photons.

  7. Neutrino Data from IceCube and its Predecessor at the South Pole, the Antarctic Muon and Neutrino Detector Array (AMANDA)

    DOE Data Explorer

    Abbasi, R.

    IceCube is a neutrino observatory for astrophysics with parts buried below the surface of the ice at the South Pole and an air-shower detector array exposed above. The international group of sponsors, led by the National Science Foundation (NSF), that designed and implemented the experiment intends for IceCube to operate and provide data for 20 years. IceCube records the interactions produced by astrophysical neutrinos with energies above 100 GeV, observing the Cherenkov radiation from charged particles produced in neutrino interactions. Its goal is to discover the sources of high-energy cosmic rays. These sources may be active galactic nuclei (AGNs) or massive, collapsed stars where black holes have formed.[Taken from http://www.icecube.wisc.edu/] The data from IceCube's predecessor experiment and detector, AMANDA, IceCube’s predecessor detector and experiment is also available at this website. AMANDA pioneered neutrino detection in ice. Over a period of years in the 1990s, detecting “strings” were buried and activated and by 2000, AMANDA was successfully recording an average of 1,000 neutrino events per year. This site also makes available many images and video from the two experiments.

  8. The "CSI" Effect: Changing the Face of Science

    ERIC Educational Resources Information Center

    Jones, Richard; Bangert, Arthur

    2006-01-01

    The authors suggest that "CSI," a public mass media product, and other television programming have greatly influenced how students, especially female students, perceive scientists at work. Perhaps the increased airing of television programs focusing on laboratory sciences has caused student perceptions of scientists to shift away from the "mad…

  9. CSI related dynamics and control issues in space robotics

    NASA Technical Reports Server (NTRS)

    Schmitz, Eric; Ramey, Madison

    1993-01-01

    The research addressed includes: (1) CSI issues in space robotics; (2) control of elastic payloads, which includes 1-DOF example, and 3-DOF harmonic drive arm with elastic beam; and (3) control of large space arms with elastic links, which includes testbed description, modeling, and experimental implementation of colocated PD and end-point tip position controllers.

  10. Development of a Spectral Model Based on Charge Transport for the Swift/BAT 32K CdZnTe Detector Array

    NASA Technical Reports Server (NTRS)

    Sato, Goro; Parsons, Ann; Hillinger, Derek; Suzuki, Masaya; Takahashi, Tadayuki; Tashiro, Makoto; Nakazawa, Kazuhiro; Okada, Yuu; Takahashi, Hiromitsu; Watanabe, Shin

    2005-01-01

    The properties of 32K CdZnTe (4 x 4 sq mm large, 2 mm thick) detectors have been studied in the pre-flight calibration of the Burst Alert Telescope (BAT) on-board the Swift Gamma-ray Burst Explorer (scheduled for launch in November 2004). In order to understand the energy response of the BAT CdZnTe array, we first quantify the mobility-lifetime (mu tau) products of carriers in individual CdZnTe detectors, which produce a position dependency in the charge induction efficiency and results in a low energy tail in the energy spectrum. Based on a new method utilizing (57)Co spectra obtained at different bias voltages, the mu tau for electrons ranges from 5.0 x 10(exp -4) to 1.0 x 10(exp -2) sq cm/V while the mu tau for holes ranges from 1.3 x 10(exp -5 to 1.8 x 10(exp -4) sq cm/V. We find that this wide distribution of mu tau products explains the large diversity in spectral shapes between CdZnTe detectors well. We also find that the variation of mu tau products can be attributed to the difference of crystal ingots or manufacturing harness. We utilize the 32K sets of extracted mu tau products to develop a spectral model of the detector. In combination with Monte Carlo simulations, we can construct a spectral model for any photon energy or any incident angle.

  11. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    SciTech Connect

    Bolotnikov, A. E. Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hossain, A.; Mahler, G.; Maritato, M.; Roy, U.; Salwen, C.; Vernon, E.; Yang, G.; James, R. B.; Hodges, D.; Lee, W.; Petryk, M.

    2015-07-15

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  12. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    SciTech Connect

    Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hodges, D.; Hossain, A.; Lee, W.; Mahler, G.; Maritato, M.; Petryk, M.; Roy, U.; Salwen, C.; Vernon, E.; Yang, G.; James, R. B.

    2015-07-28

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  13. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    DOE PAGES

    Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.; ...

    2015-07-28

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics.more » The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

  14. Digital radiography: Present detectors and future developments

    SciTech Connect

    Perez-Mendez, V.

    1990-08-01

    Present detectors for digital radiography are of two classes: real time detectors and storage (non real time) types. Present real time detectors consist of image intensifier tubes with an internal cesium iodide layer x-ray converter. Non real time detectors involve linear sweep arrays or storage detectors such as film. Future detectors discussed here can be of both types utilizing new technologies such as hydrogenated amorphous silicon photodiode arrays coupled to thin film transistor arrays. 17 refs., 10 figs.

  15. First results of a novel Silicon Drift Detector array designed for low energy X-ray fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Rachevski, Alexandre; Ahangarianabhari, Mahdi; Bellutti, Pierluigi; Bertuccio, Giuseppe; Brigo, Elena; Bufon, Jernej; Carrato, Sergio; Castoldi, Andrea; Cautero, Giuseppe; Fabiani, Sergio; Giacomini, Gabriele; Gianoncelli, Alessandra; Giuressi, Dario; Guazzoni, Chiara; Kourousias, George; Liu, Chang; Menk, Ralf Hendrik; Montemurro, Giuseppe Vito; Picciotto, Antonino; Piemonte, Claudio; Rashevskaya, Irina; Shi, Yongbiao; Stolfa, Andrea; Vacchi, Andrea; Zampa, Gianluigi; Zampa, Nicola; Zorzi, Nicola

    2016-07-01

    We developed a trapezoidal shaped matrix with 8 cells of Silicon Drift Detectors (SDD) featuring a very low leakage current (below 180 pA/cm2 at 20 °C) and a shallow uniformly implanted p+ entrance window that enables sensitivity down to few hundreds of eV. The matrix consists of a completely depleted volume of silicon wafer subdivided into 4 square cells and 4 half-size triangular cells. The energy resolution of a single square cell, readout by the ultra-low noise SIRIO charge sensitive preamplifier, is 158 eV FWHM at 5.9 keV and 0 °C. The total sensitive area of the matrix is 231 mm2 and the wafer thickness is 450 μm. The detector was developed in the frame of the INFN R&D project ReDSoX in collaboration with FBK, Trento. Its trapezoidal shape was chosen in order to optimize the detection geometry for the experimental requirements of low energy X-ray fluorescence (LEXRF) spectroscopy, aiming at achieving a large detection angle. We plan to exploit the complete detector at the TwinMic spectromicroscopy beamline at the Elettra Synchrotron (Trieste, Italy). The complete system, composed of 4 matrices, increases the solid angle coverage of the isotropic photoemission hemisphere about 4 times over the present detector configuration. We report on the layout of the SDD matrix and of the experimental set-up, as well as the spectroscopic performance measured both in the laboratory and at the experimental beamline.

  16. A deuterium-labelling mass spectrometry-tandem diode-array detector screening method for rapid discovery of naturally occurring electrophiles.

    PubMed

    Zhang, Xiaoyu; Luo, Liping; Ma, Zhongjun

    2011-07-01

    Because electrophiles regulate many signalling pathways in cells, by modifying cysteine residues in proteins, they have a wide range of biological activity. In this study, a deuterium-labelling mass spectrometry-tandem diode-array detector (MS-DAD) screening method was established for rapid discovery of naturally occurring electrophiles. Glutathione (GSH) was used as a probe and incubated with natural product extracts. To distinguish different types of electrophile, incubation was performed in two reaction solvents, H(2)O and D(2)O. Ten types of naturally occurring electrophile were chosen, on the basis of their properties, to undergo the screening assay. By using this screening method, we successfully discovered the bioactive electrophile 4-hydroxyderricin in an ethanol extract of Angelica keiskei. This electrophile had potent NAD(P)H:quinone oxidoreductase 1 (NQO1)-inducing activity at a concentration of 20 μmol L(-1).

  17. A new water-equivalent 2D plastic scintillation detectors array for the dosimetry of megavoltage energy photon beams in radiation therapy

    SciTech Connect

    Guillot, Mathieu; Beaulieu, Luc; Archambault, Louis; Beddar, Sam; Gingras, Luc

    2011-12-15

    Purpose: The objective of this work is to present a new 2D plastic scintillation detectors array (2D-PSDA) designed for the dosimetry of megavoltage (MV) energy photon beams in radiation therapy and to characterize its basic performance. Methods: We developed a 2D detector array consisting of 781 plastic scintillation detectors (PSDs) inserted into a plane of a water-equivalent phantom. The PSDs were distributed on a 26 x 26 cm{sup 2} grid, with an interdetector spacing of 10 mm, except for two perpendicular lines centered on the detection plane, where the spacing was 5 mm. Each PSD was made of a 1 mm diameter by 3 mm long cylindrical polystyrene scintillating fiber coupled to a clear nonscintillating plastic optical fiber. All of the light signals emitted by the PSDs were read simultaneously with an optical system at a rate of one measurement per second. We characterized the performance of the optical system, the angular dependency of the device, and the perturbation of dose distributions caused by the hundreds of PSDs inserted into the phantom. We also evaluated the capacity of the system to monitor complex multileaf collimator (MLC) sequences such as those encountered in step-and-shoot intensity modulated radiation therapy (IMRT) plans. We compared our results with calculations performed by a treatment planning system and with measurements taken with a 2D ionization chamber array and with a radiochromic film. Results: The detector