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1

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

2

Large area avalanche photodiode detector array upgrade for a ruby-laser Thomson scattering system  

E-print Network

Large area avalanche photodiode detector array upgrade for a ruby-laser Thomson scattering system T microchannel plate MCP detector was replaced with an array of modular large area avalanche photodiode detectors-laser head, collection optics, a Jarrell-Ash MonoSpec-27 Model 82-499 spectrometer, and avalanche photodiode

Biewer, Theodore

3

Detector telescope array: silicon--CsI(Tl)--photodiode  

NASA Astrophysics Data System (ADS)

A closely packed array of 60 telescopes was developed for use at forward angles in the 4? Array at the National Superconducting Cyclotron Laboratory at Michigan State University. The telescopes resolve isotopes and cover nearly 100% of the solid angle assigned to the array. These requirements and limitations of space and funding resulted in a number of novel features, some of which will be useful in other applications. These features include: photodiodes of arbitrary shape with no frame around the edge, replacement of aluminized Mylar with aluminum leaf, an inexpensive silicon diode leakage current monitor that presents a graph of leakage current vs detector number, and a low noise but inexpensive preamplifier chip. Experience with the array showed that compounds in the outer insulation layer of some types of coax cable can seriously contaminate a vacuum system. The use of computer aided design and computer controlled machine tools reduced the cost of the structural parts by orders of magnitude.

Norbeck, E.; Yang, L. B.; Pogodin, P.; Ingram, F. D.

1999-10-01

4

An LSO BLOCK detector for PET using an avalanche photodiode array  

Microsoft Academic Search

A Block detector, consisting of a four by four array of lutetium oxyorthosilicate (LSO) scintillator crystals coupled to a two by two avalanche photodiode (APD) array was built and tested. The detector block was 8.5 by 8.5 by 10 millimeters so that the crystals were on 2.13 millimeter centers. The APD array has an active area of approximately 9 by

M. E. Casey; H. Dautet; D. Waechter; R. Lecomte; L. Eriksson; M. Schmand

1998-01-01

5

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

6

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

Microsoft Academic Search

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

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

1982-01-01

7

Determination and pharmacokinetics of gastrodin in human plasma by HPLC coupled with photodiode array detector  

Microsoft Academic Search

In present study, an HPLC method coupled with photodiode array detector (HPLC-PDA) was established for determination and pharmacokinetics of gastrodin (GAS) in human plasma after an oral administration of GAS capsule. In the method, ethanol and dichloromethane were respectively used for deproteinization and purification during the sample preparation procedure. Separation of GAS was achieved on an AichromBond-AQ C18 column (5?m,

Xue Hai Ju; Ying Shi; Na Liu; Dong Mei Guo; Xi Cui

2010-01-01

8

UV detectors and focal plane array imagers based on AlGaN p-i-n photodiodes  

Microsoft Academic Search

The successful development of both discrete UV photodiodes and large-format UV imaging arrays consisting of 128·128 and 320·256 AlGaN p-i-n photodiodes is reported. Detectors and detector arrays have been successfully developed to sense radiation in the 300ñ365 nm visible-blind and 240ñ285 nm solar-blind portions of the UV spectral region. Details of the de- vice synthesis and processing are discussed, including

J. P. LONG; S. VARADARAAJAN; J. MATTHEWS; J. F. SCHETZINA

9

Performance of a PET detector module utilizing an array of silicon photodiodes to identify the crystal of interaction  

Microsoft Academic Search

Initial performance results for a new multilayer positron emission tomography detector module are presented. It consists of an array of 3-mm square by 30-mm deep bismuth germanate (BGO) crystals coupled on one end to a single photomultiplier tube and the opposite end to an array of 3-mm square silicon photodiodes. The photomultiplier tube provides an accurate timing pulse and energy

W. W. Moses; S. E. Derenzo; R. Nutt; W. M. Digby; C. W. Williams; M. Andreaco

1993-01-01

10

Simultaneous multielement graphite furnace atomic absorption measurements using a photodiode array detector  

NASA Astrophysics Data System (ADS)

A photodiode array detector multichannel analyser system has been coupled to a graphite furnace atomizer and tested for simultaneous multielement atomic absorption analysis. Multielement hollow cathode lamps are used as light sources and spectral lines are dispersed through a spectrograph with three selectable gratings. Multiple transmitted spectra are recorded to simultaneously determine the atomic absorption profiles of the analyte elements during the atomization stage. Atomic absorbance of individual elements is obtained by integrating the respective peak areas of the appropriate time-resolved atomic absorption spectra. The obtained sensitivities for Ni-Co-Fe are within the same order of magnitude as those from conventional single element determinations using photomultiplier tube detection. The system has also been applied for simultaneous multielement flame atomic absorption spectrometry (AAS) measurements and it has been demonstrated that background absorption can be readily corrected for both flame and graphite furnace AAS by a two-line method where non-atomic absorption lines can be chosen from the simultaneously recorded spectra.

Tong, S. L.; Chin, K. S.

1994-05-01

11

Determination and pharmacokinetics of gastrodin in human plasma by HPLC coupled with photodiode array detector.  

PubMed

In present study, an HPLC method coupled with photodiode array detector (HPLC-PDA) was established for determination and pharmacokinetics of gastrodin (GAS) in human plasma after an oral administration of GAS capsule. In the method, ethanol and dichloromethane were respectively used for deproteinization and purification during the sample preparation procedure. Separation of GAS was achieved on an AichromBond-AQ C18 column (5 microm, 150 mm x 4.6 mm) with the mobile phase of methanol-0.1% phosphoric acid solution (2:98, v/v) at a flow rate of 0.8 ml/min. The wavelength was set at 220 nm and the injection volume was 20 microl. Under the conditions, the calibration curve was linear within the concentration range of 50-4000 ng/ml with the correlation coefficient (r) of 0.99554 (weight=1/X(2)) and the lower limit of quantification (LLOQ) was 50 ng/ml. The inter- and intra-day precisions were less than 11% and the accuracies (%) were within the range of 95.55-103.78%. The extraction recoveries were over 65% with RSDs less than 5.50%. The GAS was proved to be stable under tested conditions. Thus, the method was valid enough to be applied for pharmacokinetic study of GAS in human plasma. The pharmacokinetic parameters of GAS in human plasma after an oral administration of 200 mg GAS capsule were described as: C(max), 1484.55+/-285.05 ng/ml; T(max), 0.81+/-0.16 h; t(1/2alpha), 3.78+/-2.33 h; t(1/2beta), 6.06+/-3.20 h; t(1/2Ka), 0.18+/-0.53 h; K(12), 0.18+/-0.41/h; K(21), 0.20+/-0.16/h; K(10), 4.11+/-15.81/h; V1/F, 180.35+/-89.44 L; CL/F, 62.50+/-140.03 l/h; AUC(0-->t), 5619.41+/-1972.88 (ng/ml) h; and AUC(0-->infinity), 7210.26+/-3472.74 (ng/ml) h, respectively. These will be useful for the clinical application of GAS. PMID:20542476

Ju, Xue Hai; Shi, Ying; Liu, Na; Guo, Dong Mei; Cui, Xi

2010-07-15

12

Determination of synthetic acaricides residues in beeswax by high-performance liquid chromatography with photodiode array detector.  

PubMed

A multiresidue HPLC method for identification and quantification of the synthetic acaricides fluvalinate, coumaphos, bromopropylate and its metabolite 4,4'-dibromobenzophenone in beeswax has been developed. Different techniques were tested and modified. The method consists of a sample preparation with isooctane followed by solid phase extraction using Florisil columns. Determination of the synthetic acaricides is achieved by HPLC with a photodiode array detector. Analytical performance of the proposed method, including sensitivity, accuracy and precision was satisfactory. The LOD for the analytes varied between 0.1 and 0.2 microg g(-1) wax and the recoveries between 70 and 110%. Relative standard deviation of the repeatability of the method is <15% and reproducibility is <31%. PMID:17386431

Adamczyk, Sabine; Lázaro, Regina; Pérez-Arquillué, Consuelo; Herrera, Antonio

2007-01-01

13

Linear terrestrial laser scanning using array avalanche photodiodes as detectors for rapid three-dimensional imaging.  

PubMed

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. PMID:21124523

Cai, Yinqiao; Tong, Xiaohua; Tong, Peng; Bu, Hongyi; Shu, Rong

2010-12-01

14

Avalanche Photodiode Arrays for Optical Communications Receivers  

NASA Technical Reports Server (NTRS)

An avalanche photodiode (APD) array for ground-based optical communications receivers is investigated for the reception of optical signals through the turbulent atmosphere. Kolmogorov phase screen simulations are used to generate realistic spatial distributions of the received optical field. It is shown that use of an APD array for pulse-position modulation detection can improve performance by up to 4 dB over single APD detection in the presence of turbulence, but that photon-counting detector arrays yield even greater gains.

Srinivasan, M.; Vilnrotter, V.

2001-01-01

15

Chromatographic fingerprinting analysis of Zhizhu Wan preparation by high-performance liquid chromatography coupled with photodiode array detector  

PubMed Central

Background: Traditional Chinese medicine (TCM) formula has been used for over 1000 years and most of them contain complicate chemical constituents. Chromatographic fingerprinting has been widely accepted as a crucial method for qualitative and quantitative analyses for TCM. Zhi Zhu Wan (ZZW), a classical Chinese medical formula, has been commonly used for the treatment of gastrointestinal disease, which pose a serious challenge to its quality control. Materials and Methods: In this work, a sensitive and reliable method of high-performance liquid chromatography coupled with photodiode array detector (HPLC-PDA) was developed to control the quality of ZZW for chemical fingerprint analysis and quantitative analysis of four major bioactive constituents, including hesperidin, naringin, neohesperidin, and atractylenolide I. The chromatographic separation was performed on a Waters Symmetry C18 column (4.6 mm × 250 mm, 5 ?m particle size), with an aqueous 0.095% phosphate acid and acetonitrile mobile phase gradient. Results: Optimization of other experimental conditions was validated with satisfactory accuracy, precision, repeatability, and recovery. In quantitative analysis, the four components showed good regression (R > 0.9994) within test ranges, and the recovery method ranged from 99.32% to 100.630%. HPLC fingerprints of the ZZW samples were compared by performing similarity analysis. Conclusion: The results indicated that the newly developed HPLC-PDA fingerprint method would be suitable for quality control of ZZW. PMID:25422548

Sun, Hui; Chen, Xi; Zhang, Aihua; Sakurai, Tetsuro; Jiang, Jinzhong; Wang, Xijun

2014-01-01

16

Nuclear resonant scattering measurements on 57Fe by multichannel scaling with a 64-pixel silicon avalanche photodiode linear-array detector  

NASA Astrophysics Data System (ADS)

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 ?m2) with a pixel pitch of 150 ?m and depletion depth of 10 ?m. An ultrafast frontend circuit allows the X-ray detector to obtain a high output rate of >107 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 57Fe.

Kishimoto, S.; Mitsui, T.; Haruki, R.; Yoda, Y.; Taniguchi, T.; Shimazaki, S.; Ikeno, M.; Saito, M.; Tanaka, M.

2014-11-01

17

The Use of Self-scanned Silicon Photodiode Arrays for Astronomical Spectrophotometry  

NASA Technical Reports Server (NTRS)

The use of a Reticon self scanned silicon photodiode array for precision spectrophotometry is discussed. It is shown that internal errors are + or - 0.003 mag. Observations obtained with a photodiode array are compared with observations obtained with other types of detectors with agreement, from 3500 A to 10500 A, of 1%. The photometric properties of self scanned photodiode arrays are discussed. Potential pitfalls are given.

Cochran, A. L.

1984-01-01

18

Avalanche photodiodes for the CMS detector  

Microsoft Academic Search

The CERN LHC experiment CMS has selected for the readout of the barrel crystal calorimeter a 5×5 mm2 avalanche photodiode (APD) manufactured by Hamamatsu Photonics. In the detector we will equip each crystal with two APDs for a total of 122400 diodes. As the calorimeter will be almost completely inaccessible during the life of the detector, the assurance that they

K. Deiters; A. Dorokhov; Q. Ingram; S. Nicol; I. Musienko; B. Patel; D. Renker; S. Reucroft; R. Rusack; T. Sakhelashvili; A. Singovski; J. Swain; P. Vikas

2000-01-01

19

Avalanche Photodiode Arrays for Optical Communications Receivers  

Microsoft Academic Search

An avalanche photodiode (APD) array for ground-based optical communications receivers is investigated for the reception of optical signals through the turbulent atmosphere. Kolmogorov phase screen simulations are used to generate realistic spatial distributions of the received optical fleld. It is shown that use of an APD array for pulse-position modulation detection can improve performance by up to 4 dB over

M. Srinivasan; V. Vilnrotter

20

Current isolating epitaxial buffer layers for high voltage photodiode array  

DOEpatents

An array of photodiodes in series on a common semi-insulating substrate has a non-conductive buffer layer between the photodiodes and the semi-insulating substrate. The buffer layer reduces current injection leakage between the photodiodes of the array and allows optical energy to be converted to high voltage electrical energy.

Morse, Jeffrey D. (Martinez, CA); Cooper, Gregory A. (Pleasant Hill, CA)

2002-01-01

21

Design of Low Power CMOS Read-Out with TDI Function for Infrared Linear Photodiode Array Detectors  

NASA Technical Reports Server (NTRS)

A new low voltage CMOS infrared readout circuit using the buffer-direct injection method is presented. It uses a single supply voltage of 1.8 volts and a bias current of 1uA. The time-delay integration technique is used to increase the signal to noise ratio. A current memory circuit with faulty diode detection is used to remove dark current for background compensation and to disable a photodiode in a cell if detected as faulty. Simulations are shown that verify the circuit that is currently in fabrication in 0.5ym CMOS technology.

Vizcaino, Paul; Ramirez-Angulo, Jaime; Patel, Umesh D.

2007-01-01

22

Quantitative and Chemical Fingerprint Analysis for the Quality Evaluation of Isatis indigotica based on Ultra-Performance Liquid Chromatography with Photodiode Array Detector Combined with Chemometric Methods  

PubMed Central

A simple and reliable method of ultra-performance liquid chromatography with photodiode array detector (UPLC-PDA) was developed to control the quality of Radix Isatidis (dried root of Isatis indigotica) for chemical fingerprint analysis and quantitative analysis of eight bioactive constituents, including R,S-goitrin, progoitrin, epiprogoitrin, gluconapin, adenosine, uridine, guanosine, and hypoxanthine. In quantitative analysis, the eight components showed good regression (R > 0.9997) within test ranges, and the recovery method ranged from 99.5% to 103.0%. The UPLC fingerprints of the Radix Isatidis samples were compared by performing chemometric procedures, including similarity analysis, hierarchical clustering analysis, and principal component analysis. The chemometric procedures classified Radix Isatidis and its finished products such that all samples could be successfully grouped according to crude herbs, prepared slices, and adulterant Baphicacanthis cusiae Rhizoma et Radix. The combination of quantitative and chromatographic fingerprint analysis can be used for the quality assessment of Radix Isatidis and its finished products. PMID:22942750

Shi, Yan-Hong; Xie, Zhi-Yong; Wang, Rui; Huang, Shan-Jun; Li, Yi-Ming; Wang, Zheng-Tao

2012-01-01

23

Quantitative and Chemical Fingerprint Analysis for the Quality Evaluation of Isatis indigotica based on Ultra-Performance Liquid Chromatography with Photodiode Array Detector Combined with Chemometric Methods.  

PubMed

A simple and reliable method of ultra-performance liquid chromatography with photodiode array detector (UPLC-PDA) was developed to control the quality of Radix Isatidis (dried root of Isatis indigotica) for chemical fingerprint analysis and quantitative analysis of eight bioactive constituents, including R,S-goitrin, progoitrin, epiprogoitrin, gluconapin, adenosine, uridine, guanosine, and hypoxanthine. In quantitative analysis, the eight components showed good regression (R > 0.9997) within test ranges, and the recovery method ranged from 99.5% to 103.0%. The UPLC fingerprints of the Radix Isatidis samples were compared by performing chemometric procedures, including similarity analysis, hierarchical clustering analysis, and principal component analysis. The chemometric procedures classified Radix Isatidis and its finished products such that all samples could be successfully grouped according to crude herbs, prepared slices, and adulterant Baphicacanthis cusiae Rhizoma et Radix. The combination of quantitative and chromatographic fingerprint analysis can be used for the quality assessment of Radix Isatidis and its finished products. PMID:22942750

Shi, Yan-Hong; Xie, Zhi-Yong; Wang, Rui; Huang, Shan-Jun; Li, Yi-Ming; Wang, Zheng-Tao

2012-01-01

24

ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays  

NASA Technical Reports Server (NTRS)

The objective of this work was to develop a new class of readout integrated circuit (ROIC) arrays to be operated with Geiger avalanche photodiode (GPD) arrays, by integrating multiple functions at the pixel level (smart-pixel or active pixel technology) in 250-nm CMOS (complementary metal oxide semiconductor) processes. In order to pack a maximum of functions within a minimum pixel size, the ROIC array is a full, custom application-specific integrated circuit (ASIC) design using a mixed-signal CMOS process with compact primitive layout cells. The ROIC array was processed to allow assembly in bump-bonding technology with photon-counting infrared detector arrays into 3-D imaging cameras (LADAR). The ROIC architecture was designed to work with either common- anode Si GPD arrays or common-cathode InGaAs GPD arrays. The current ROIC pixel design is hardwired prior to processing one of the two GPD array configurations, and it has the provision to allow soft reconfiguration to either array (to be implemented into the next ROIC array generation). The ROIC pixel architecture implements the Geiger avalanche quenching, bias, reset, and time to digital conversion (TDC) functions in full-digital design, and uses time domain over-sampling (vernier) to allow high temporal resolution at low clock rates, increased data yield, and improved utilization of the laser beam.

Vasile, Stefan; Lipson, Jerold

2012-01-01

25

Characterization of avalanche photodiode arrays for temporally resolved photon counting  

NASA Astrophysics Data System (ADS)

The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) is a next-generation campaign aimed at measuring the earth-moon separation with millimeter precision. Doing so requires precision measurements of the time-of-flight of photons between the earth and moon. APOLLO will utilize new technology in the form of avalanche photodiode (APD) arrays to detect and time-tag the lunar return photons. The APD arrays were provided by Massachusetts Institute of Technology, Lincoln Laboratory but with no accompanying electronic circuitry for biasing or reading out the detectors. I describe the design, construction and testing of the electronics to bias the arrays and detect photons. Once a final prototype version of the electronics was developed, I characterized the temporal and spatial response of the detectors at two different wavelengths: 786 nm and 668 nm. A simple model of APD performance was developed and compared reasonably well with the experimental data. This model was used to predict the detector performance at 532 nm—the wavelength used for APOLLO.

Strasburg, Jana Dee

2004-10-01

26

Photodiode  

NSDL National Science Digital Library

This Quicktime presentation explains the basics of the photodiode. Some concepts that are explained include the photodiode package, photodiode illumination, internal connections, photodiode chip, photon absorption and electron-hole pair generation.

Van Zeghbroeck, Bart Jozef

27

Validated stability-indicating methods for the simultaneous determination of amiloride hydrochloride, atenolol, and chlorthalidone using HPTLC and HPLC with photodiode array detector.  

PubMed

Two stability-indicating chromatographic methods are described for simultaneous determination of amiloride hydrochloride (AMI), atenolol (ATE), and chlorthalidone (CHL) in combined dosage forms. The first method was based on HPTLC separation of the three drugs followed by densitometric measurements of their bands at 274 nm. The separation was carried out on Merck HPTLC silica gel 60F254 aluminum sheets using chloroform-methanol-ammonia 27%, w/w (9 + 2 + 0.3, v/v/v) mobile phase. Analysis data was used for the linear regression graph in the range of 0.1-0.5, 0.8-5.0, and 0.3-1.5 microg/band for AMI, ATE, and CHL, respectively. The second method was based on an RP-HPLC separation of the cited drugs performed on an RP stainless steel C18 analytical column (250 x 4.6 mm id) with a gradient elution system of methanol and 0.05 M aqueous phosphate buffer adjusted to pH 4 as the mobile phase, at the flow rate of 1.0 mL/min. Quantitation was achieved with photodiode array detection at 275 nm for AMI and 225 nm for ATE and CHL. The calibration graphs for each drug were rectilinear in the range of 2-50, 25-150, and 2-100 microg/mL for AMI, ATE, and CHL, respectively. The proposed chromatographic methods were successfully applied for determination of the investigated drugs in pharmaceutical preparations. Both methods were validated in compliance with International Conference on Harmonization guidelines in terms of linearity, accuracy, precision, robustness, LOD, and LOQ. PMID:23767356

Youssef, Rasha M; Maher, Hadir M; El-Kimary, Eman I; Hassan, Ekram M; Barary, Magda H

2013-01-01

28

Photodiode arrays having minimized cross-talk between diodes  

DOEpatents

Photodiode arrays are formed with close diode-to-diode spacing and minimized cross-talk between diodes in the array by isolating the diodes from one another with trenches that are formed between the photodiodes in the array. The photodiodes are formed of spaced regions in a base layer, each spaced region having an impurity type opposite to that of the base layer to define a p-n junction between the spaced regions and the base layer. The base layer meets a substrate at a boundary, with the substrate being much more heavily doped than the base layer with the same impurity type. The trenches extend through the base layer and preferably into the substrate. Minority carriers generated by absorption of light photons in the base layer can only migrate to an adjacent photodiode through the substrate. The lifetime and the corresponding diffusion length of the minority carriers in the substrate is very short so that all minority carriers recombine in the substrate before reaching an adjacent photodiode.

Guckel, Henry (Madison, WI); McNamara, Shamus P. (Madison, WI)

2000-10-17

29

Effect of a polywell leometry on a CMOS photodiode array  

Microsoft Academic Search

The effect of a polywell geometry hybridized with a stacked gradient poly-homojunction architecture, on the response of a CMOs compatible photodiode array was simulated. Crosstalk and sensitivity improved compared to the polywell geometry alone, for both back and front illumination.

Paul V. Jansz; Steven Hinckley; Graham Wild

2010-01-01

30

Effect of a Polywell geometry on a CMOS Photodiode Array  

Microsoft Academic Search

The effect of a polywell geometry hybridized with a stacked gradient poly-homojunction architecture, on the response of a CMOs compatible photodiode array was simulated. Crosstalk and sensitivity improved compared to the polywell geometry alone, for both back and front illumination

Paul V Jansz; Steven Hinckley; Graham Wild

2010-01-01

31

Avalanche photodiode based detector for beam emission spectroscopy  

SciTech Connect

An avalanche photodiode based (APD) detector for the visible wavelength range was developed for low light level, high frequency beam emission spectroscopy (BES) experiments in fusion plasmas. This solid state detector has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it has internal gain. This paper describes the developed detector as well as the noise model of the electronic circuit. By understanding the noise sources and the amplification process, the optimal amplifier and APD reverse voltage setting can be determined, where the signal-to-noise ratio is the highest for a given photon flux. The calculations are compared to the absolute calibration results of the implemented circuit. It was found that for a certain photon flux range, relevant for BES measurements ({approx_equal}10{sup 8}-10{sup 10} photons/s), the new detector is superior to both photomultipliers and photodiodes, although it does not require cryogenic cooling of any component. The position of this photon flux window sensitively depends on the parameters of the actual experimental implementation (desired bandwidth, detector size, etc.) Several detector units based on these developments have been built and installed in various tokamaks. Some illustrative results are presented from the 8-channel trial BES system installed at Mega-Ampere Spherical Tokamak (MAST) and the 16-channel BES system installed at the Torus Experiment for Technology Oriented Research (TEXTOR).

Dunai, D.; Zoletnik, S.; Sarkoezi, J. [KFKI Research Institute for Particle and Nuclear Physics, EURATOM Association, P.O. Box 49, H-1525 Budapest (Hungary); Field, A. R. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

2010-10-15

32

Infrared imaging arrays based on superlattice photodiodes  

NASA Astrophysics Data System (ADS)

We report on the status of focal plane arrays (FPAs) based on GaSb/InAs type-II superlattice diodes grown by molecular beam epitaxy (MBE) and designed for infrared absorption in the 2-5?m and 8-10?m bands. Recent LWIR devices have produced differential resistance-area product greater than 100 Ohmcm2 at 80K with a long wavelength cutoff of approximately 10?m. The measured quantum efficiency of these front-side illuminated devices is close to 25% in the 8-9 ?m range. MWIR devices have produced detectivities as high as 8x10 13 Jones with a differential resistance-area product greater than 3x10 7 Ohmcm2 at 80K with a long wavelength cutoff of approximately 3.7?m. The measured quantum efficiency of these front-side illuminated MWIR devices is close to 40% in the 2-3?m range at low temperature and increases to over 60% near room temperature. Initial results on SiO II and epitaxial-regrowth based passivation techniques are also presented, as well as images from the first lot of 1kx1k MWIR arrays and our latest 256x256 LWIR arrays.

Hill, Cory J.; Soibel, Alexander; Keo, Sam A.; Mumolo, Jason M.; Gunapala, Sarath D.; Rhiger, David R.; Kvaas, Robert E.; Harris, Sean F.

2008-04-01

33

Effect of temperature on silicon PIN photodiode radiation detectors  

NASA Astrophysics Data System (ADS)

One of the noise sources of a semiconductor radiation detector is thermal noise, which degrades the performance, such as the energy resolution and unexpected random pulse signals. In this study, PIN photodiode radiation detectors, with different active areas were designed and fabricated for an experimental comparison of the energy resolutions for different temperatures and capacitances by using a Ba-133 calibration gamma-ray source. The experimental temperature was approximately in the range from -7 to 24 °C and was controlled by using a peltier device. The design considerations and the electrical characteristics, such as the I-V and the C-V characteristics, are also addressed.

Kim, Han Soo; Jeong, Manhee; Kim, Young Soo; Ha, Jang Ho; Cho, Seong Yeon

2014-03-01

34

An Array of Photodiodes for Monitoring Hydrocarbons Combustions Burners  

NASA Astrophysics Data System (ADS)

A non-intrusive method for monitoring hydrocarbons, gas and oil flames, is introduced in this paper. The method is based in a radiometry measurement of the flame, which is implemented by using an array of silicon photodiodes with interference optical filters. The array is designed to cover wavelengths for evaluating the formation and behaviour of excited CH* and C2* radicals. These radicals CH* and C2* can be detected at centre wavelengths of 432 nm and 516 nm respectively. The radiometry analysis for monitoring non-confined oil flames was checked by a radiometer, using crosscorrelation data. These radicals are also measured for gas flames in the reaction region for a confined flame. Simple and low cost electronic was designed to drive the array of silicon photodiodes and they were set in an optical system and in a data acquisition system. The tests reported demonstrate that the flame condition can be adequately monitored for different air excess, different axial position as well as for different firing rate. Indeed, experimental test were taken for two power level: low and high firing rate. The fast response, the non-intrusive character and the instantaneous measurement of information make the proposed optical sensor a key to develop advances control strategies, which can be used successfully in combustion processes.

Arias, P. Luis; Torres, I. Sergio; Sbárbaro, H. Daniel; Farías, F. Oscar

2008-04-01

35

Single-Crystalline Silicon-Based Heterojunction Photodiode Arrays on Flexible Plastic Substrates  

Microsoft Academic Search

A silicon-based photodiode array was fabricated on a flexible polyethylene terephthalate substrate using a trans- fer printing technique. A heterojunction structure composed of a 15-nm-thick highly doped hydrogenated amorphous-silicon (n + a-Si:H) layer and a 3-µm-thick p-type single-crystal silicon (p c-Si) membrane layer was adopted as the active layer of the flexible photodiode. The highly ordered photodiode array formed on

Sangwook Lee; Juree Hong; Ja Hoon Koo; Seulah Lee; Kwanghyun Lee; Seongil Im; Taeyoon Lee

2011-01-01

36

Compact multispectral photodiode arrays using micropatterned dichroic filters  

NASA Astrophysics Data System (ADS)

The next generation of multispectral instruments requires significant improvements in both spectral band customization and portability to support the widespread deployment of application-specific optical sensors. The benefits of spectroscopy are well established for numerous applications including biomedical instrumentation, industrial sorting and sensing, chemical detection, and environmental monitoring. In this paper, spectroscopic (and by extension hyperspectral) and multispectral measurements are considered. The technology, tradeoffs, and application fits of each are evaluated. In the majority of applications, monitoring 4-8 targeted spectral bands of optimized wavelength and bandwidth provides the necessary spectral contrast and correlation. An innovative approach integrates precision spectral filters at the photodetector level to enable smaller sensors, simplify optical designs, and reduce device integration costs. This method supports user-defined spectral bands to create application-specific sensors in a small footprint with scalable cost efficiencies. A range of design configurations, filter options and combinations are presented together with typical applications ranging from basic multi-band detection to stringent multi-channel fluorescence measurement. An example implementation packages 8 narrowband silicon photodiodes into a 9x9mm ceramic LCC (leadless chip carrier) footprint. This package is designed for multispectral applications ranging from portable color monitors to purpose- built OEM industrial and scientific instruments. Use of an eight-channel multispectral photodiode array typically eliminates 10-20 components from a device bill-of-materials (BOM), streamlining the optical path and shrinking the footprint by 50% or more. A stepwise design approach for multispectral sensors is discussed - including spectral band definition, optical design tradeoffs and constraints, and device integration from prototype through scalable volume production. Additional customization options are explored for application-specific OEM sensors integrated into portable devices using multispectral photodiode arrays.

Chandler, Eric V.; Fish, David E.

2014-05-01

37

Development of Low Noise, BackSide Illuminated Silicon Photodiode Arrays 1  

E-print Network

in the device perimeter due to the metallization used to contact the photodiode. The arrays are read out with a custom integrated circuit [3], and back illumination also simplifies the mechanical interface betweenDevelopment of Low Noise, Back­Side Illuminated Silicon Photodiode Arrays 1 S.E. Holland Member

38

Maia X-ray Microprobe Detector Array System  

NASA Astrophysics Data System (ADS)

Maia is an advanced system designed specifically for scanning x-ray fluorescence microprobe applications. It consists of a large array of photodiode detectors and associated signal processing, closely coupled to an FPGA-based control and analysis system. In this paper we will describe the architecture and construction of the system.

Siddons, D. P.; Kirkham, R.; Ryan, C. G.; De Geronimo, G.; Dragone, A.; Kuczewski, A. J.; Li, Z. Y.; Carini, G. A.; Pinelli, D.; Beuttenmuller, R.; Elliott, D.; Pfeffer, M.; Tyson, T. A.; Moorhead, G. F.; Dunn, P. A.

2014-04-01

39

Nano-Multiplication-Region Avalanche Photodiodes and Arrays  

NASA Technical Reports Server (NTRS)

Nano-multiplication-region avalanche photodiodes (NAPDs), and imaging arrays of NAPDs integrated with complementary metal oxide/semiconductor (CMOS) active-pixel-sensor integrated circuitry, are being developed for applications in which there are requirements for high-sensitivity (including photoncounting) detection and imaging at wavelengths from about 250 to 950 nm. With respect to sensitivity and to such other characteristics as speed, geometric array format, radiation hardness, power demand of associated circuitry, size, weight, and robustness, NAPDs and arrays thereof are expected to be superior to prior photodetectors and arrays including CMOS active-pixel sensors (APSs), charge-coupled devices (CCDs), traditional APDs, and microchannelplate/ CCD combinations. Figure 1 depicts a conceptual NAPD array, integrated with APS circuitry, fabricated on a thick silicon-on-insulator wafer (SOI). Figure 2 presents selected aspects of the structure of a typical single pixel, which would include a metal oxide/semiconductor field-effect transistor (MOSFET) integrated with the NAPD. The NAPDs would reside in silicon islands formed on the buried oxide (BOX) layer of the SOI wafer. The silicon islands would be surrounded by oxide-filled insulation trenches, which, together with the BOX layer, would constitute an oxide embedding structure. There would be two kinds of silicon islands: NAPD islands for the NAPDs and MOSFET islands for in-pixel and global CMOS circuits. Typically, the silicon islands would be made between 5 and 10 m thick, but, if necessary, the thickness could be chosen outside this range. The side walls of the silicon islands would be heavily doped with electron-acceptor impurities (p+-doped) to form anodes for the photodiodes and guard layers for the MOSFETs. A nanoscale reach-through structure at the front (top in the figures) central position of each NAPD island would contain the APD multiplication region. Typically, the reach-through structure would be about 0.1 microns in diameter and between 0.3 and 0.4 nm high. The top layer in the reach-through structure would be heavily doped with electron-donor impurities (n+-doped) to make it act as a cathode. A layer beneath the cathode, between 0.1 and 0.2 nm thick, would be p-doped to a concentration .10(exp 17)cu cm. A thin n+-doped polysilicon pad would be formed on the top of the cathode to protect the cathode against erosion during a metal-silicon alloying step that would be part of the process of fabricating the array.

Zheng, Xinyu; Pain, Bedabrata; Cunningham, Thomas

2008-01-01

40

Linear array of photodiodes to track a human speaker for video recording  

NASA Astrophysics Data System (ADS)

Communication and collaboration using stored digital media has garnered more interest by many areas of business, government and education in recent years. This is due primarily to improvements in the quality of cameras and speed of computers. An advantage of digital media is that it can serve as an effective alternative when physical interaction is not possible. Video recordings that allow for viewers to discern a presenter's facial features, lips and hand motions are more effective than videos that do not. To attain this, one must maintain a video capture in which the speaker occupies a significant portion of the captured pixels. However, camera operators are costly, and often do an imperfect job of tracking presenters in unrehearsed situations. This creates motivation for a robust, automated system that directs a video camera to follow a presenter as he or she walks anywhere in the front of a lecture hall or large conference room. Such a system is presented. The system consists of a commercial, off-the-shelf pan/tilt/zoom (PTZ) color video camera, a necklace of infrared LEDs and a linear photodiode array detector. Electronic output from the photodiode array is processed to generate the location of the LED necklace, which is worn by a human speaker. The computer controls the video camera movements to record video of the speaker. The speaker's vertical position and depth are assumed to remain relatively constant- the video camera is sent only panning (horizontal) movement commands. The LED necklace is flashed at 70Hz at a 50% duty cycle to provide noise-filtering capability. The benefit to using a photodiode array versus a standard video camera is its higher frame rate (4kHz vs. 60Hz). The higher frame rate allows for the filtering of infrared noise such as sunlight and indoor lighting-a capability absent from other tracking technologies. The system has been tested in a large lecture hall and is shown to be effective.

DeTone, D.; Neal, H.; Lougheed, R.

2012-12-01

41

Nano-multiplication region avalanche photodiodes and arrays  

NASA Technical Reports Server (NTRS)

An avalanche photodiode with a nano-scale reach-through structure comprising n-doped and p-doped regions, formed on a silicon island on an insulator, so that the avalanche photodiode may be electrically isolated from other circuitry on other silicon islands on the same silicon chip as the avalanche photodiode. For some embodiments, multiplied holes generated by an avalanche reduces the electric field in the depletion region of the n-doped and p-doped regions to bring about self-quenching of the avalanche photodiode. Other embodiments are described and claimed.

Zheng, Xinyu (Inventor); Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

2011-01-01

42

Application of a photodiode-array optical turbulence sensor to wind studies in complex terrain  

Microsoft Academic Search

A digital photodiode-array optical turbulence sensor was used to gather data simultaneously with analog optical anemometer measurements during the July 1979 ASCOT experiment. This system provided useful information regarding the uniformity of optical turbulence used by the optical anemometer to derive cross-path wind speeds. Wind speeds derived from digital analysis of the photodiode-array intensities also provided an independent measure of

W. M. Porch; T. J. Green

1980-01-01

43

Solid state neutron detector array  

DOEpatents

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.

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

1999-08-17

44

Solid state neutron detector array  

DOEpatents

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.

Seidel, John G. (Pittsburgh, PA); Ruddy, Frank H. (Monroeville, PA); Brandt, Charles D. (Mount Lebanon, PA); Dulloo, Abdul R. (Pittsburgh, PA); Lott, Randy G. (Pittsburgh, PA); Sirianni, Ernest (Monroeville, PA); Wilson, Randall O. (Greensburg, PA)

1999-01-01

45

SWIR to LWIR HDVIP HgCdTe detector array performance  

Microsoft Academic Search

DRS uses LPE-grown SWIR, MWIR and LWIR HgCdTe material to fabricate High-Density Vertically Integrated Photodiode (HDVIP) architecture detectors. 2.5 mum, 5.3 mum and 10.5 mum cutoff detectors have been fabricated into linear arrays as technology demonstrations targeting remote sensing programs. This paper presents 320 x 6 array configuration technology demonstrations' performance of HDVIP HgCdTe detectors and single detector noise data.

A. I. D'Souza; M. G. Stapelbroek; L. Dawson; P. Ely; C. Yoneyama; J. Reekstin; M. R. Skokan; M. A. Kinch; P. K. Liao; M. J. Ohlson; P. J. Ronci; T. Teherani; H. D. Shih; J. Robinson

2006-01-01

46

Ultra-low noise single-photon detector based on Si avalanche photodiode.  

PubMed

We report operation and characterization of a lab-assembled single-photon detector based on commercial silicon avalanche photodiodes (PerkinElmer C30902SH, C30921SH). Dark count rate as low as 5 Hz was achieved by cooling the photodiodes down to -80 °C. While afterpulsing increased as the photodiode temperature was decreased, total afterpulse probability did not become significant due to detector's relatively long deadtime in a passively-quenched scheme. We measured photon detection efficiency >50% at 806 nm. PMID:21974576

Kim, Yong-Su; Jeong, Youn-Chang; Sauge, Sebastien; Makarov, Vadim; Kim, Yoon-Ho

2011-09-01

47

Analysis of flavonoids from lotus (Nelumbo nucifera) leaves using high performance liquid chromatography/photodiode array detector tandem electrospray ionization mass spectrometry and an extraction method optimized by orthogonal design.  

PubMed

The extraction protocol of flavonoids from lotus (Nelumbo nucifera) leaves was optimized through an orthogonal design. The solvent was the most important factor comparing solvent, solvent:tissue ratio, extraction time, and temperature. The highest yield of flavonoids was achieved with 70% methanol-water and a solvent:tissue ratio of 30:1 at 4 °C for 36 h. The optimized analytical method for HPLC was a multi-step gradient elution using 0.5% formic acid (A) and CH?CN containing 0.1% formic acid (B), at a flow rate of 0.6 mL/min. Using this optimized method, thirteen flavonoids were simultaneously separated and identified by high performance liquid chromatography coupled with photodiode array detection/electrospray ionization mass spectrometry (HPLC/DAD/ESI-MS(n)). Five of the bioactive compounds are reported in lotus leaves for the first time. The flavonoid content of the leaves of three representative cultivars was assessed under the optimized extraction and HPLC analytical conditions, and the seed-producing cultivar 'Baijianlian' had the highest flavonoid content compared with rhizome-producing 'Zhimahuoulian' and wild floral cultivar 'Honglian'. PMID:22265782

Chen, Sha; Wu, Ben-Hong; Fang, Jin-Bao; Liu, Yan-Ling; Zhang, Hao-Hao; Fang, Lin-Chuan; Guan, Le; Li, Shao-Hua

2012-03-01

48

Ultra high performance liquid chromatography with photodiode array detector and quadrupole time-of-flight tandem mass spectrometry coupled with discriminant analysis to evaluate Angelicae pubescentis radix from different regions.  

PubMed

A rapid and effective method was developed for the qualitative and quantitative analysis of the major chemical constituents in Angelicae pubescentis radix by ultra high performance liquid chromatography with photodiode array detection and quadrupole time-of-flight tandem mass spectrometry. The chromatographic separation was achieved on an ACQUITY UHPLC BEH C18 column (2.1 × 100 mm, 1.7 ?m). Nine phenolic acids, 30 coumarins, bisabolangelone, and adenosine were identified by quadrupole time-of-flight tandem mass spectrometry. All calibration curves exhibited good linearity (r > 0.9996) within the linear ranges. The relative standard deviation calculated for intraday and interday precision, stability, and accuracy were <5%. The mean recovery ranged from 95.8 to 106%. The overall limits of detection and quantification were 0.025-0.160 and 0.100-0.560 ?g/mL, respectively. Discriminant analysis was investigated as a method for evaluating the quality of the samples with 100% correction in their classification. The results demonstrated that the developed method could successfully be used to differentiate samples from different regions and could be a helpful tool for detection and confirmation of the quality of traditional Chinese medicines. PMID:25044521

Ge, Ai-Hua; Ma, Wen-Fang; Wang, Chun-Peng; Li, Jin; He, Jun; Liu, Er-Wei; Adelakum, Tiwalade Adegoke; Zhang, Bo-Li; Gao, Xiumei; Chang, Yan-Xu

2014-09-01

49

X-ray imaging sensor arrays on foil using solution processed organic photodiodes and organic transistors  

NASA Astrophysics Data System (ADS)

We demonstrate organic imaging sensor arrays fabricated on flexible plastic foil with the solution processing route for both photodiodes and thin film transistors. We used the photovoltaic P3HT:PCBM blend for fabricating the photodiodes using spin coating and pentacene as semiconductor material for the TFTs. Photodiodes fabricated with P3HT:PCBM absorb in the green part of the visible spectrum which matches with the typical scintillator output wavelength. The arrays consist of 32x32 pixels with variation in pixel resolution of 200?mx200?m, 300?mx300?m and of 1mmx1mm. The accurate reproducibility of shadow images of the objects demonstrates the potential of these arrays for imaging purposes. We also demonstrate that the crosstalk is relatively insignificant despite the fact that the active photodiode forms a continuous layer in the array. Since both photodiodes and TFTs are made of organic material, they are processed at low temperatures below 150°C on foil which means that these imaging sensors can be flexible, light weight and low cost when compared to conventional amorphous silicon based imaging sensors on rigid substrates. In combination with a scintillator on top of the arrays, we show the potential of these arrays for the X-ray imaging applications.

Kumar, Abhishek; Moet, Date; van der Steen, Jan-Laurens; Tripathi, Ashutosh; Rodriguez, Francisco G.; Maas, Joris; Simon, Matthias; Reutten, Walter; Douglas, Alexander; Raaijmakers, Rob; Malinowski, Pawel E.; Myny, Kris; Shafique, Umar; Andriessen, Ronn; Heremans, Paul; Gelinck, Gerwin

2014-05-01

50

Development of a large pixel, spectrally optimized, pinned photodiode/interline charge coupled device (CCD) detector for the Earth Observing System (EOS)/Moderate-Resolution Imaging Spectrometer-Tilt (MODIS-T) instrument  

NASA Technical Reports Server (NTRS)

A pinned photodiode/interline CCD Detector Array is under development for the EOS/MODIS-T project. Outstanding features of the device include large pixels, spectrally optimized fill factors, and blooming protection. The detector has 30 spatial rows and 32 spectral columns. The device layout is split into two halves; each half has its own detector area, storage area, and output structure.

Ewin, Audrey J.; Jhabvala, Murzy; Shu, Peter K.

1991-01-01

51

64-element photodiode array for scintillation detection of x-rays  

NASA Astrophysics Data System (ADS)

The paper presents the design, technology and parameters of a new, silicon 64-element linear photodiode array developed at the Institute of Electron Technology (ITE) for the detection of scintillations emitted by CsI scintillators (??550 nm). The arrays are used in a device for examining the content of containers at border crossings under development at the National Centre for Nuclear Research. Two arrays connected with a scintillator block (128 CsI scintillators) form a 128-channel detection module. The array consists of 64 epiplanar photodiode structures (5.1 × 7.2 mm) and a 5.3 mm module. p+-?-n+ photodiode structures are optimised for the detection of radiation of ?? 550 nm wavelength with no voltage applied (photovoltaic mode). The structures are mounted on an epoxy-glass laminate substrate, copper-clad on both sides, on which connections with a common anode and separate cathode leads are located. The photosensitive surface of photodiodes is covered with a special silicone gel, which protects photodiodes against the mechanical impact of scintillators

Wegrzecki, Maciej; Wolski, Dariusz; Bar, Jan; Budzy?ski, Tadeusz; Ch?opik, Arkadiusz; Grabiec, Piotr; K?os, Helena; Panas, Andrzej; Piotrowski, Tadeusz; S?ysz, Wojciech; Stolarski, Maciej; Szmigiel, Dariusz; Wegrzecka, Iwona; Zaborowski, Micha?

2014-08-01

52

Inexpensive photodiode arrays for use in rocket plume and hot source monitoring and diagnostics  

NASA Astrophysics Data System (ADS)

The spectroscopic analysis of plume emissions is a non-intrusive method which has been used to check for fatigue and possible damage throughout the pumps and other mechanisms in a rocket motor or engine. These components are made of various alloys. Knowing the composition of the alloys and for which parts they are used, one can potentially determine from the emissions in the plume which component is failing. Currently, optical multichannel analyser systems are being used which utilize charge coupled devices, cost tens of thousands of dollars, are somewhat delicate, and usually require cooling. We have developed two rugged instruments using less expensive linear photodiode arrays as detectors. A high-resolution system was used to detect atomic emission lines while a low-resolution system was used to detect molecular emission bands. We have also written data acquisition software and built electronic circuits to control the arrays and collect data. While the National Aeronautics and Space Administration has used similar systems for characterization of the space shuttle main engine, the emissions from other rocket systems have not been surveyed so well. The two instruments described will be utilized to study hybrid rocket emissions at the University of Arkansas-Little Rock hybrid rocket facility.

Snider, Dallas; Shanks, Robert; Cole, Reagan; Hudson, M. Keith

2003-09-01

53

Surface plasmon resonance imaging biosensor based on silicon photodiode array  

NASA Astrophysics Data System (ADS)

The detection limit of surface plasmon resonance imaging (SPRI) biosensor is constrained in part by the SPR biochip and in part by the resolution of the optical intensity of detecting instruments. In this paper, silicon photodiode is proposed as the optical intensity detecting element instead of the traditionally used charge coupled device (CCD), combining with high resolution analog/digital converter, this method can efficiently reduce the cost and increase the sensitivity of the SPRI system while keeping its virtue of multiple channels real time detecting. Based on this method, An SPRI experimental system with two channels is designed and the optical intensity of each channel is detected by a photodiode. By carrying out testing experiments using sucrose solution with different concentrations (corresponding to different refractive index), the system sensitivity of 10-6 refractive index unit (RIU) is obtained.

Yin, Shaoyun; Sun, Xiuhui; Deng, Qiling; Xia, Liangping; Du, Chunlei

2010-11-01

54

Massively Parallel MRI Detector Arrays  

PubMed Central

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

Keil, Boris; Wald, Lawrence L

2013-01-01

55

A prototype high-resolution animal positron tomograph with avalanche photodiode arrays and LSO crystals  

Microsoft Academic Search

To fully utilize positron emission tomography (PET) as a non-invasive tool for tissue characterization, dedicated instrumentation is being developed which is specially suited for imaging mice and rats. Semiconductor detectors, such as avalanche photodiodes (APDs), may offer an alternative to photomultiplier tubes for the readout of scintillation crystals. Since the scintillation characteristics of lutetium oxyorthosilicate (LSO) are well matched to

Sibylle I. Ziegler; Bernd J. Pichler; Guido Boening; Magdalena Rafecas; Wendelin Pimpl; Eckart Lorenz; Norbert Schmitz; Markus Schwaiger

2001-01-01

56

Grating spectrograph integrated with photodiode array in InGaAsP\\/InGaAs\\/InP  

Microsoft Academic Search

A grating spectrograph integrated monolithically for the first time in the InGaAsP system with a photodiode array for a dense WDM application is presented for the 1.5 ?m wavelength region. The chip provides 42 wavelength channels with a spacing of 4 mm, a channel crosstalk of approximately -15 dB, an internal photodiode efficiency of 90%, and a photodiode capacitance of

C. Cremer; N. Emeis; M. Schier; G. Heise; G. Ebbinghaus; L. Stoll

1992-01-01

57

Application of a silicon photodiode array for solar edge tracking in the Halogen Occultation Experiment  

NASA Technical Reports Server (NTRS)

The optical and electronic design of the Halogen Occultation Experiment (HALOE) elevation sunsensor is described. This system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned, monolithic charge coupled device. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the HALOE science instantaneous-field-of-view (IFOV) across the vertical solar diameter during instrument calibration, and then maintain the science IFOV four arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 0.7 micrometer operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability. The HALOE instrument is a gas correlation radiometer that is now being developed by NASA Langley Research Center for the Upper Atmospheric Research Satellite.

Mauldin, L. E., III; Moore, A. S.; Stump, C. S.; Mayo, L. S.

1985-01-01

58

Improved Optical Communications Performance Using Adaptive Optics with an Avalanche Photodiode Detector  

Microsoft Academic Search

We present predicted and experimentally measured gains in communications per- formance of a laboratory-based, free-space optical communications system through the use of adaptive optics (AO). A commercially available avalanche photodiode detector (APD) is used in the receiver for signal detection. Background noise and atmospheric turbulence field conditions were simulated in the laboratory using an integration sphere and a specially designed

M. W. Wright; M. Srinivasan; K. Wilson

2005-01-01

59

Performance comparison of barrier detectors and HgCdTe photodiodes  

NASA Astrophysics Data System (ADS)

Barrier detectors are designed to reduce the dark current associated with Shockley-Read (SR) processes and to decrease the influence of surface leakage current without impeding photocurrent (signal). As a consequence, the absence of a depletion region in barrier detectors offers a way to overcome the disadvantage of the large depletion dark current. Therefore, they are typically implemented in materials with relatively poor SR lifetimes, such as all III-V compounds. It is shown here that despite numerous advantages of III-V barrier detectors over present-day detection technologies, including reduced tunneling and surface leakage currents, normal-incidence absorption, and suppressed Auger recombination, the promise of a superior performance with these detectors in comparison with HgCdTe photodiodes has not been realized yet. The dark current density is higher than that of bulk HgCdTe photodiodes, especially in the mid-wavelength infrared range.

Martyniuk, Piotr; Rogalski, Antoni

2014-10-01

60

Effect of different drying methods on the quality of Angelicae Sinensis Radix evaluated through simultaneously determining four types of major bioactive components by high performance liquid chromatography photodiode array detector and ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry.  

PubMed

In the present study, the effect of drying methods on the quality of Angelicae Sinensis Radix (DG), was evaluated by newly developed high performance liquid chromatography photodiode array detector (HPLC-DAD) and ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS). Ten major bioactive components including two phenolic acids, two hydroxyl phthalides, four alkyl phthalides and two phthalide dimers were selected as evaluation chemical markers and the newly-established method was qualitatively and quantitatively validated. DG slices and whole roots dried in shade, sun light, hot air, vacuum, microwave, far infrared ray and combination of microwave and far infrared ray as well as the fresh DG samples were determined by the established methods. DG slices dried in hot air kept the similar chemical composition to that of fresh DG, while DG whole roots dried in vacuum retained highest contents of the major components. Coniferyl ferulate and ligustilide degraded significantly in DG slices dried by microwave, far infrared ray and their combination. The influence of such chemical changes induced by different drying methods on the bioactivities of DG warrants further investigation, so that the optimal drying method can be obtained for the standardization of DG herb. PMID:24561333

Bai, Ying-Jia; Kong, Ming; Xu, Jin-Di; Zhang, Xiao-Lin; Zhou, Shan-Shan; Wang, Xiao-Ning; Liu, Li-Fang; Li, Song-Lin

2014-06-01

61

Study of Geiger avalanche photo-diodes (GAPDs) applications to pixel tracking detectors  

NASA Astrophysics Data System (ADS)

The effort at the UB and CNM to study the feasibility of using standard CMOS technology Geiger avalanche photo-diodes (GAPDs) for pixel tracking detectors is reported. Generally APDs are used as photon detector devices. The possibility of using APDs in Geiger mode (that is reverse-biased above breakdown) for direct particle detection is the purpose of the ongoing R&D program, which tries to exploit GAPDs' features suitable for particle detection.

Graugés, E.; Comerma, A.; Garrido, L.; Gascón, D.; Trenado, J.; Diéguez, A.; Vilà, A.; Arbat, A.; Freixas, L.; Hidalgo, S.; Fernández, P.; Flores, D.; Lozano, M.

2010-05-01

62

Ultralow-noise readout circuit with an avalanche photodiode: toward a photon-number-resolving detector.  

PubMed

The charge-integration readout circuit was fabricated to achieve an ultralow-noise preamplifier for photoelectrons generated in an avalanche photodiode with linear mode operation at 77 K. To reduce the various kinds of noise, the capacitive transimpedance amplifier was used and consisted of low-capacitance circuit elements that were cooled with liquid nitrogen. As a result, the readout noise is equal to 3.0 electrons averaged for a period of 40 ms. We discuss the requirements for avalanche photodiodes to achieve photon-number-resolving detectors below this noise level. PMID:17304297

Tsujino, Kenji; Akiba, Makoto; Sasaki, Masahide

2007-03-01

63

Temperature and nonlinearity corrections for a photodiode array spectrometer used in the field  

SciTech Connect

Temperature and nonlinearity effects are two important factors that limit the use of photodiode array spectrometers. Usually the spectrometer is calibrated at a known temperature against a reference source of a particular spectral radiance, and then it is used at different temperatures to measure sources of different spectral radiances. These factors are expected to be problematic for nontemperature-stabilized instruments used for in-the-field experiments, where the radiant power of the site changes continuously with the sun tilt. This paper describes the effect of ambient temperature on a nontemperature-stabilized linear photodiode array spectrometer over the temperature range from 5 deg. C to 40 deg. C. The nonlinearity effects on both signal amplification and different levels of radiant power have also been studied and are presented in this paper.

Salim, Saber G. R.; Fox, Nigel P.; Theocharous, Evangelos; Sun, Tong; Grattan, Kenneth T. V.

2011-02-20

64

Stressed detector arrays for airborne astronomy  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

65

Performance comparison of barrier detectors and HgCdTe photodiodes  

NASA Astrophysics Data System (ADS)

Recently, a new strategy used to achieve high operation temperature (HOT) infrared photodetectors including III-V compound materials (bulk materials and type-II superlattices) and cascade devices has been observed. Another method to reduce detector's dark current is reducing volume of detector material via a concept of photon trapping detector. The barrier detectors are designed to reduce dark current associated with Shockley-Read (SR) processes and to decrease influence of surface leakage current without impeding photocurrent (signal). In consequence, absence of a depletion region in barrier detectors offers a way to overcome the disadvantage of large depletion dark currents. So, they are typically implemented in materials with relatively poor SR lifetimes, such as all III-V compounds. From considerations presented in the paper results that despite numerous advantages of III-V barrier detectors over present-day detection technologies, including reduced tunneling and surface leakage currents, normal-incidence absorption, and suppressed Auger recombination, the promise of a superior performance of these detectors in comparison to HgCdTe photodiodes, has not been yet realized. The dark current density is higher than that of bulk HgCdTe photodiodes, especially in MWIR range. To attain their full potential, the following essential technological limitations such as short carrier lifetime, passivation, and heterostructure engineering, need to be overcome.

Martyniuk, P.; Rogalski, A.

2014-06-01

66

A new silicon avalanche photodiode photon counting detector module for astronomy  

Microsoft Academic Search

A new Silicon avalanche photodiode photon counting detector module with a peak detection efficiency of 45% and a maximum counting rate of more than 3,000,000cts\\/sec is described and its performance assessed over a range of operating conditions. The module should prove ideal for a wide variety of astronomical instrumentation as it covers the spectral range 350–1050nm and is compact, rugged

N. S. Nightingale; Cavendish Labomtov

1990-01-01

67

Performance characteristics of BGO-silicon avalanche photodiode detectors for PET  

Microsoft Academic Search

Spectroscopic and timing characteristics of a gammaray detector based on silicon avalanche photodiodes (APD) and bismuth germanate (BGO) scintillators are reported. The APD used in this work is a large area (25 mm²) device of the ''reach through'' type having a quantum efficiency of 70% at 480 nm. When coupled to a 5X5X3 mm³ BGO crystal, its spectroscopic performance is

R. Lecomte; A. W. Lightstone; R. J. McIntyre; D. Schmitt

1985-01-01

68

Development of a testbed for flexible a-Si:H photodiode sensing arrays  

NASA Astrophysics Data System (ADS)

Large area, flexible sensing arrays for imaging, biochemical sensing and radiation detection are now possible with the development of flexible active matrix display technology. In particular, large-area flexible imaging arrays can provide considerable advancement in defense and security industries because of their inherent low manufacturing costs and physical plasticity that allows for increased adaptability to non-planar mounting surfaces. For example, a flexible array of photodetectors and lenslets formed into a cylinder could image simultaneously with a 360 degree view without the need for expensive bulky optics or a gimbaled mount. Here we report the design and development of a scalable 16x16 pixel testbed for flexible sensor arrays using commercial-off-the-shelf (COTS) parts and demonstrate the capture of a shadow image with an array of photodiodes and active pixel sensors on a plastic substrate. The image capture system makes use of an array of low-noise, InGaZnO active pixel amplifiers to detect changes in current in 2.4 ?m-thick reverse-biased a-Si:H PIN diodes. A thorough characterization of the responsivity, detectivity, and optical gain of an a- Si:H photodiode is also provided. At the back end, analog capture circuitry progressively scans the array and constructs an image based on the electrical activity in each pixel. The use of correlated-double-sampling to remove fixed pattern noise is shown to significantly improve spatial resolution due to process variations. The testbed can be readily adapted for the development of neutron, alpha-particle, or X-ray detection arrays given an appropriate conversion layer.

Dominguez, Alfonso; Kunnen, George; Vetrano, Michael; Smith, Joseph; Marrs, Michael; Allee, David R.

2013-05-01

69

Initial characterization of a position-sensitive photodiode/BGO detector for PET (positron emission tomography)  

SciTech Connect

We present initial results of a position-sensitive photodiode/BGO detector for high resolution, multi-layer positron emission tomography (PET). Position sensitivity is achieved by dividing the 3 mm /times/ 20 mm rectangular photosensitive area along the diagonal to form two triangular segments. Each segment was individually connected to a low-noise amplifier. The photodiodes and crystals were cooled to /minus/100/degree/C to reduce dark current and increase the BGO signal. With an amplifier peaking time of 17 ..mu..sec, the sum of the signals (511 keV photopeak) was 3200 electrons with a full width at half maximum (fwhm) of 750 electrons. The ratio of one signal to the sum determined the depth of interaction with a resolution of 11 mm fwhm. 27 refs., 7 figs.

Derenzo, S.E.; Moses, W.W.; Jackson, H.G.; Turko, B.T.; Cahoon, J.L.; Geyer, A.B.; Vuletich, T.

1988-11-01

70

A linear photodiode array employed in a short range laser triangulation obstacle avoidance sensor. M.S. Thesis; [Martian roving vehicle sensor  

NASA Technical Reports Server (NTRS)

An opto-electronic receiver incorporating a multi-element linear photodiode array as a component of a laser-triangulation rangefinder was developed as an obstacle avoidance sensor for a Martian roving vehicle. The detector can resolve the angle of laser return in 1.5 deg increments within a field of view of 30 deg and a range of five meters. A second receiver with a 1024 elements over 60 deg and a 3 meter range is also documented. Design criteria, circuit operation, schematics, experimental results and calibration procedures are discussed.

Odenthal, J. P.

1980-01-01

71

Geiger-mode avalanche photodiode focal plane arrays for three-dimensional imaging LADAR  

NASA Astrophysics Data System (ADS)

We report on the development of focal plane arrays (FPAs) employing two-dimensional arrays of InGaAsP-based Geiger-mode avalanche photodiodes (GmAPDs). These FPAs incorporate InP/InGaAs(P) Geiger-mode avalanche photodiodes (GmAPDs) to create pixels that detect single photons at shortwave infrared wavelengths with high efficiency and low dark count rates. GmAPD arrays are hybridized to CMOS read-out integrated circuits (ROICs) that enable independent laser radar (LADAR) time-of-flight measurements for each pixel, providing three-dimensional image data at frame rates approaching 200 kHz. Microlens arrays are used to maintain high fill factor of greater than 70%. We present full-array performance maps for two different types of sensors optimized for operation at 1.06 ?m and 1.55 ?m, respectively. For the 1.06 ?m FPAs, overall photon detection efficiency of >40% is achieved at <20 kHz dark count rates with modest cooling to ~250 K using integrated thermoelectric coolers. We also describe the first evalution of these FPAs when multi-photon pulses are incident on single pixels. The effective detection efficiency for multi-photon pulses shows excellent agreement with predictions based on Poisson statistics. We also characterize the crosstalk as a function of pulse mean photon number. Relative to the intrinsic crosstalk contribution from hot carrier luminescence that occurs during avalanche current flows resulting from single incident photons, we find a modest rise in crosstalk for multi-photon incident pulses that can be accurately explained by direct optical scattering.

Itzler, Mark A.; Entwistle, Mark; Owens, Mark; Patel, Ketan; Jiang, Xudong; Slomkowski, Krystyna; Rangwala, Sabbir; Zalud, Peter F.; Senko, Tom; Tower, John; Ferraro, Joseph

2010-09-01

72

Application of pulsed UV laser for dicing of arrays and linear of photodiodes based on MCT solid solution  

NASA Astrophysics Data System (ADS)

The modern systems of vision in infrared spectrum (IR) require elaboration of large-area nondefective imaging area with small pitch (less 40 ?m) IR FPA. One of the directions is fabrication hybrid FPA, consisting of several of arrays of photodiodes based on MCT films (Hg xCd 1-xTe on GaAs substrates) and readout circuits on silicon. Substitution of photodiodes array of large-area imaging area on few arrays of smaller image size, allows having the imaging area of the required size without fault pixels. The main requirement is the permanent period of photodetectors on component imaging areas. without loss of pixels on lines of gaps of the butting between arrays. Using concentrated laser radiation, for scribing the surfaces MCT film on GaAs substrate, under concrete conditions, allows to realize offered above direction. The determination of the border of zone of the influence of the laser radiation on electric characteristic of p-n junction of the MCT films and technological ways of the reduction of area of influence of the laser radiation are presented in work. We had studied the change of parameters of photodiodes on base MCT films depending on distances before laser dicing grooves and condition of the laser radiation. As source of the laser radiation we used pulsed UV laser (LGI-21) at 0,34 ?m wavelength with pulse duration 7 ns, frequency of repetition 50 - 100 Hz and power in pulse 2 KW. We founded condition of the laser dicing on distances 18 - 20 ?m from photodiodes, when initial current-voltage characteristics of photodiodes are saved. We designed method of the laser dicing of linear photodiodes on MCT films, and we used it to create of multichips hybrid IR FPA. The result is non damage dicing of linear photodiodes on MCT films (? c =12 ?m) on distances 18 - 20 ?m from p-n junctions.

Novoselov, A. R.; Klimenko, A. G.; Vasilyev, V. V.

2007-05-01

73

Si:As BIB detector arrays  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

74

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

DOEpatents

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.

Strauss, C.E.

1997-11-18

75

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

DOEpatents

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.

Strauss, Charlie E. (Santa Fe, NM)

1997-01-01

76

Predictions of silicon avalanche photodiode detector performance in water vapor differential absorption lidar  

NASA Technical Reports Server (NTRS)

Performance analyses are presented which establish that over most of the range of signals expected for a down-looking differential absorption lidar (DIAL) operated at 16 km the silicon avalanche photodiode (APD) is the preferred detector for DIAL measurements of atmospheric water vapor in the 730 nm spectral region. The higher quantum efficiency of the APD's, (0.8-0.9) compared to a photomultiplier's (0.04-0.18) more than offsets the higher noise of an APD receiver. In addition to offering lower noise and hence lower random error the APD's excellent linearity and impulse recovery minimize DIAL systematic errors attributable to the detector. Estimates of the effect of detector system parameters on overall random and systematic DIAL errors are presented, and performance predictions are supported by laboratory characterization data for an APD receiver system.

Kenimer, R. L.

1988-01-01

77

Optoelectronic measurement for parameters of high-speed flying objects based on laser screen and photodiode array  

NASA Astrophysics Data System (ADS)

The impacting or penetrating power of high-speed flying object can be evaluated by its mass and velocity, so the velocity and the mass are two key parameters. Here we present an optoelectronic measurement method for parameters of high-speed flying objects based on parallel laser screen and photodiode array. The system consists of two thin laser screens with parallel each other and certain distance, orthogonal two dimensional photodiode arrays, data acquisition module, control module and data transmission processing module. When the object flies through the thin screen, the incident light of some photodiodes at the corresponding position is blocked and the output states of the corresponding photodiodes are changed. The flying position, which can be used to correct the distance error, velocity and the overall dimension of the object are determined by high-speed sampling and storing all the output states of photodiode array at any sampling moment when the object flying through the thin screens. We employed a line-shaped laser diode and a Fresnel lens with long-focal-length and aberration-free to generate parallel laser screen. The high-speed large-amount parallel data sampling module is comprised of four FPGA-based boards with built-in FIFO buffer memory, and the control module is constructed by one FPGA board and a FLASH memory. Functions simulation and experiment results of the FPGA-based data acquisition storage and the LabVIEW-based data processing indicate that the method and the design are feasible.

Zhao, Donge; Zhang, Bin; Liu, Ji; Xiao, Kai-jia; Wang, Lei

2013-09-01

78

Thermopile Detector Arrays for Space Science Applications  

NASA Technical Reports Server (NTRS)

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.

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

79

Performance characteristics of BGO-silicon avalanche photodiode detectors for PET  

SciTech Connect

Spectroscopic and timing characteristics of a gammaray detector based on silicon avalanche photodiodes (APD) and bismuth germanate (BGO) scintillators are reported. The APD used in this work is a large area (25 mm/sup 2/) device of the ''reach through'' type having a quantum efficiency of 70% at 480 nm. When coupled to a 5X5X3 mm/sup 3/ BGO crystal, its spectroscopic performance is found to be superior to that of a PMT coupled to the same crystal, owing largely to its higher quantum efficiency. At room temperature, the APD achieves better energy resolution than any other (unity gain) solid state photodetector currently available; at -15 /sup 0/C, its spectroscopic performance is comparable to that of large area p-i-n photodiodes at -150 /sup 0/C. Preliminary measurements show that the timing performance of the new detector allows it to be used for both energy and coincidence discrimination in positron emission tomography (PET). Results obtained with a realistic BGO crystal shape and size for PET are also presented. Limitations and possible improvements are discussed.

Lecomte, R.; Lightstone, A.W.; McIntyre, R.J.; Schmitt, D.

1985-02-01

80

Signal-to-noise ratio of Geiger-mode avalanche photodiode single-photon counting detectors  

NASA Astrophysics Data System (ADS)

Geiger-mode avalanche photodiodes (GM-APDs) use the avalanche mechanism of semiconductors to amplify signals in individual pixels. With proper thresholding, a pixel will be either "on" (avalanching) or "off." This discrete detection scheme eliminates read noise, which makes these devices capable of counting single photons. Using these detectors for imaging applications requires a well-developed and comprehensive expression for the expected signal-to-noise ratio (SNR). This paper derives the expected SNR of a GM-APD detector in gated operation based on gate length, number of samples, signal flux, dark count rate, photon detection efficiency, and afterpulsing probability. To verify the theoretical results, carrier-level Monte Carlo simulation results are compared to the derived equations and found to be in good agreement.

Kolb, Kimberly

2014-08-01

81

Large-area, low-noise, high-speed, photodiode-based fluorescence detectors with fast overdrive recovery  

NASA Astrophysics Data System (ADS)

Two large-area, low-noise, high-speed fluorescence detectors have been built. One detector consists of a photodiode with an area of 28mm×28mm and a low-noise transimpedance amplifier. This detector has a input light-equivalent spectral noise density of less than 3pW/?Hz , can recover from a large scattered light pulse within 10?s, and has a bandwidth of at least 900 kHz. The second detector consists of a 16-mm-diam avalanche photodiode and a low-noise transimpedance amplifier. This detector has an input light-equivalent spectral noise density of 0.08pW/?Hz , also can recover from a large scattered light pulse within 10?s, and has a bandwidth of 1 MHz.

Bickman, S.; DeMille, D.

2005-11-01

82

Determination of nitroaromatic explosives and their degradation products in unsaturated-zone water samples by high-performance liquid chromatography with photodiode-array, mass spectrometric, and tandem mass spectrometric detection  

USGS Publications Warehouse

Mass spectrometry and tandem mass spectrometry, coupled by a thermospray interface to a high-performance liguid chromatography system and equipped with a photodiode array detector, were used to determine the presence of nitroaromatic explosives and their degradation products in USA unsaturated-zone water samples. Using this approach, the lower limits of quantitation for explosives determined by mass spectrometry in this study typically ranged from 10 to 100 ng/l.

Gates, P.M.; Furlong, E.T.; Dorsey, T.F.; Burkhardt, M.R.

1996-01-01

83

High-resolution ionization detector and array of such detectors  

DOEpatents

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.

McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)

2001-01-16

84

Modeling Charge Collection in Detector Arrays  

NASA Technical Reports Server (NTRS)

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).

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

2003-01-01

85

Monolithic short wave infrared (SWIR) detector array  

NASA Technical Reports Server (NTRS)

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.

1983-01-01

86

Neutron detector characterization for SCINTIA array  

SciTech Connect

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)

Matei, C.; Hambsch, F. J.; Oberstedt, S. [EC-JRC - Inst. for Reference Materials and Measurements, B-2440 Geel (Belgium)

2011-07-01

87

Status of direct detector and array development  

NASA Technical Reports Server (NTRS)

Programs are now underway to develop and demonstrate the detector/array technology needed for the Space Infrared Telescope Facility (SIRTF), Large Deployable Reflector (LDR), and other future NASA missions. The development goal is to achieve focal plane sensitivities, at extended integration times over the 2 to 700 microns range, limited only by the low astrophysical backgrounds encountered in cryogenic telescopes such as SIRTF. Dramatic progress has been made in the last 2 to 3 years in integrated array and detector systems for low background astronomical applications. With the broadly based developments and lab characterizations now underway for SIRTF and similar space applications, coupled with the rapidly expanding art and science of ground based astronomical imagery with arrays, the potential for effective utilization of arrays with LDR appears to be very good.

Mccreight, Craig R.

1988-01-01

88

Design and development of multicolor detector arrays  

Microsoft Academic Search

Multi-color infrared (IR) focal planes are required for high performance sensor applications. These sensors will require multi-color focal plane arrays (FPA) that will cover various wavelengths of interest in MWIR\\/LWIR and LWIR\\/VLWIR bands. There has been a significant progress in HgCdTe detector technology for multi-color MWIR\\/LWIR and LWIR\\/VLWIR focal plane arrays [1,2,3]. Two-color IR FPA eliminate the complexity of multiple

Ashok K. Sood; E. James Egerton; Yash R. Puri; Enrico Bellotti; Latika S. R. Becker; Raymond S. Balcerak; Siva Sivananthan

2004-01-01

89

Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector  

NASA Technical Reports Server (NTRS)

The purpose of this program was to develop single-photon-sensitive short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) avalanche photodiode (APD) receivers based on linear-mode HgCdTe APDs, for application by NASA in light detection and ranging (lidar) sensors. Linear-mode photon-counting APDs are desired for lidar because they have a shorter pixel dead time than Geiger APDs, and can detect sequential pulse returns from multiple objects that are closely spaced in range. Linear-mode APDs can also measure photon number, which Geiger APDs cannot, adding an extra dimension to lidar scene data for multi-photon returns. High-gain APDs with low multiplication noise are required for efficient linear-mode detection of single photons because of APD gain statistics -- a low-excess-noise APD will generate detectible current pulses from single photon input at a much higher rate of occurrence than will a noisy APD operated at the same average gain. MWIR and LWIR electron-avalanche HgCdTe APDs have been shown to operate in linear mode at high average avalanche gain (M > 1000) without excess multiplication noise (F = 1), and are therefore very good candidates for linear-mode photon counting. However, detectors fashioned from these narrow-bandgap alloys require aggressive cooling to control thermal dark current. Wider-bandgap SWIR HgCdTe APDs were investigated in this program as a strategy to reduce detector cooling requirements.

Huntington, Andrew

2013-01-01

90

Acquisition and tracking performance measurements for a high speed area array detector system  

NASA Technical Reports Server (NTRS)

A proof-of-concept (POC) demonstration system has been developed which demonstrates acquisition, tracking and point-ahead angle sensing for a space optical communications terminal utilizing a single high speed area array detector. The detector is the 128 x 128 pixel Kodak HS-40 photodiode array. It has 64 parallel readout channels and can operate at frames rates up to 40,000 frames/sec with rms readout noise of 20 photoelectrons. A windowing scheme and special purpose digital signal processing electronics are employed to implement acquisition and tracking algorithms. The system operates at greater than 1 kHz sample (frame) rates. Acquisition can be performed in as little as 30 milliseconds with less than 1 picowatt of 0.85 micron beacon power on the detector. At the same power level, the rms tracking accuracy is approximately 1/16 pixel. Results of system analysis and measurements using the POC system are presented.

Short, R. C.; Cosgrove, M.; Clark, D. L.; Martino, A.; Park, H.; Seery, B.

1991-01-01

91

Centroid tracking with area array detectors  

NASA Technical Reports Server (NTRS)

A computer program (ALGEVAL) has been developed to simulate the position estimating behavior of a centroid estimator algorithm using data typical of optical point spread function data recorded by an area array detector. Typical results are shown of varying detector properties and optical point spread function types. The detector parameters currently available for study include read noise mean value, dark current mean value and spatial variation, charge transfer efficiency and point spread function location, saturation level, signal level and pixel size. The program is capable of calculating any order centroid using an array size from 2 x 2 to 15 x 15 pixels. The output of the program is either a performance map, histogram data or tabluar data. A number of further developments are recommended.

Glavich, T. A.

1986-01-01

92

A silicon avalanche photodiode detector circuit for Nd:YAG laser scattering  

SciTech Connect

A silicon avalanche photodiode with an internal gain of about 50 to 100 is used in a temperature controlled environment to measure the Nd:YAG laser Thomson scattered spectrum in the wavelength range from 700 to 1150 nm. A charge sensitive preamplifier has been developed for minimizing the noise contribution from the detector electronics. Signal levels as low as 20 photoelectrons (S/N = 1) can be detected. Measurements show that both the signal and the variance of the signal vary linearly with the input light level over the range of interest, indicating Poisson statistics. The signal is processed using a 100 ns delay line and a differential amplifier which subtracts the low frequency background light component. The background signal is amplified with a computer controlled variable gain amplifier and is used for an estimate of the measurement error, calibration, and Z{sub eff} measurements of the plasma. The signal processing has been analyzed using a theoretical model to aid the system design and establish the procedure for data error analysis. 4 refs., 5 figs.

Hsieh, C.L.; Haskovec, J.; Carlstrom, T.N.; DeBoo, J.C.; Greenfield, C.M.; Snider, R.T.; Trost, P.

1990-06-01

93

Hybridization process for back-illuminated silicon Geiger-mode avalanche photodiode arrays  

E-print Network

We present a unique hybridization process that permits high-performance back-illuminated silicon Geiger-mode avalanche photodiodes (GM-APDs) to be bonded to custom CMOS readout integrated circuits (ROICs) - a hybridization ...

Schuette, Daniel R.

94

Direct powder introduction inductively coupled plasma atomic emission spectrometry with a photodiode array spectrometer  

NASA Astrophysics Data System (ADS)

A direct powder introduction inductively coupled plasma (DPI-ICP) atomic emission system has been coupled to a PLASMARRAY (LECO Inc.) photodiode array spectrometer. Chelex-100 samples containing spikes of elements ranging from 11 ppm to 1470 ppm have been used to evaluate the precision of element to element ratios, and for the estimation of the detection limits of 11 elements. Detection limits for Cd (0.11 ppm), Hg (1.7 ppm), Sc (2.1 ppm), Y (1.8 ppm) and Cu (3 ppm) were calculated for introduction of dry Chelex-100 powder. The precision of the ratio of emission intensities of Ni, Sn, Co, Mn and Y to the emission intensity of In (considered to be the internal standard element) were 4%, 2%, 2%, 2% and 3% relative standard deviation respectively, for 15 repeat 10 s integration measurements while introducing Chelex-100 into the plasma. Mixtures of a geological reference material (including NIM-D, NIM-G, NIM-L, NIM-N, NIM-P, or NIM-S) and Chelex-100 (1:3 by weight) were used to evaluate system performance with complex samples. It was considered impractical to carry out measurements on these samples with more than a few slots of the multielement spectral preselection mask open. The relative standard deviation (R.S.D.) of the ratio of elements contained in the geological sample vs those on the Chelex-100 were between 2% and 16%. The R.S.D. of the ratio of elements wherein both were found on the geological material was between 2 and 8%. Detection limits for Ni (7 ppm), Cr (25 to 85 ppm) and Y (1.5 ppm) were estimated for the geological materials (1:3 by weight with Chelex-100).

De Silva, K. Nimalasiri; Guevremont, Roger

95

The SAPHIRA Near-Infrared Avalanche Photodiode Array: Telescope Deployments and Future Developments  

NASA Astrophysics Data System (ADS)

We present our recent achievements of the Selex SAPHIRA APD arrays, which this year have seen deployment at three different telescopes, most notably demonstrating tip-tilt wavefront sensing in conjunction with the Palomar 1.5-m Telescope's Robo-AO system. A cooperative effort to provide enhanced speckle nulling capability to the SCExAO instrument on the Subaru telescope is also underway. We present the progress and development timeframe for the SAPHIRA and expected future applications, including targets and observational parameter space we expect the detectors to open to the astronomical community.

Atkinson, Dani Eleanor; Hall, Donald; Baranec, Christoph

2015-01-01

96

Development of the ORRUBA Silicon Detector Array  

SciTech Connect

High quality radioactive beams have recently made possible the measurement of (d,p) reactions on unstable nuclei in inverse kinematics, which can yield information on the development of single-neutron structure away from stability, and are of astrophysical interest due to the proximity to suggested r-process paths. The Oak Ridge Rutgers University Barrel Array (ORRUBA) is a new high solid-angular coverage array, composed of two rings of silicon detectors, optimized for measuring (d,p) reactions. A partial implementation has been used to measure (d,p) reactions on nuclei around the N = 82 shell closure.

Pain, S. D. [Rutgers University; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Chae, K. Y. [University of Tennessee, Knoxville (UTK); Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Hatarik, Robert [Rutgers University; Johnson, M. S. [Oak Ridge Associated Universities (ORAU); Jones, K. L. [University of Tennessee, Knoxville (UTK); Kapler, R. [University of Tennessee, Knoxville (UTK); Kozub, R. L. [Tennessee Technological University; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; O'Malley, Patrick [Rutgers University; Smith, Michael Scott [ORNL; Thomas, J. S. [Rutgers University

2009-01-01

97

Avalanche photodiodes - No longer a laboratory curiosity  

Microsoft Academic Search

Recent advances in avalanche photodiodes (APD) are reviewed. Carrier transit times 1-10 nsec are stressed, and APD noise is compared to photomultiplier noise in the visible and IR. Applications of APD are outlined: laser rangefinders (pulsed or swept-frequency swept-FM CW lasers), detectors in optical communications systems (line-of-sight or fiber optics systems), large-area detectors comprising an array of modules, soft X-ray

R. J. McIntyre; P. P. Webb

1977-01-01

98

Noise equivalent temperature difference performance of an IR detector in a hybrid focal plane array  

NASA Astrophysics Data System (ADS)

Theoretical expressions to calculate the signal-to-noise ratio of an IR detector in a direct injection readout hybrid focal plane array (FPA) are developed in this paper. The theory takes into account the effect of shift of operating point of the pixel with small variations in scene temperature and contribution of shunt resistance due to surface leakage currents in the photodiode. These expressions are then used to calculate the noise equivalent temperature difference (NETD) performance of the IR detector in the FPA. The role of buffered direct injection (BDI) circuit in improving the NETD performance of hybrid pixels in a LWIR mercury cadmium telluride FPA array is analyzed. The results of our calculations show that the individual pixels in a LWIR HgCdTe FPA would not function to their ultimate performance and in certain conditions may even exhibit erratic behaviour in the absence of BDI interface.

Gopal, Vishnu

1995-10-01

99

2.4 ?m GaInAsSb Mesa Photodiode Detectors: Leakage Currents and Ultimate Performance  

NASA Astrophysics Data System (ADS)

Short-wave infrared photodiodes play an important role in areas such as molecular sensing, thermophotovoltaics, and astronomical study of galaxy, star, and planetary formation. Here we present results and analysis of uncoated, unpassivated, GaInAsSb mesa photodiodes. We have currently achieved room temperature peak specific detectivity D*=6x10^10 Jones, dynamic resistance of 25 ?-cm^2, and quantum efficiency of 50%. Devices are limited primarily by sidewall leakage currents, initially due to generation-recombination, and over time due to Ohmic leakage from buildup of sidewall oxides. Based on material parameters obtained in this as well as other studies, ultimate diode performance is predicted, and compared to extended-wave InGaAs/InP and HgCdTe detectors.

Prineas, John; Yager, Jeff; Olesberg, Jon; Seydmohamadi, Shahram

2008-03-01

100

SQUID Multiplexers for Cryogenic Detector Arrays  

NASA Technical Reports Server (NTRS)

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.

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

101

Design of a back-illuminated, crystallographically etched, silicon-on-sapphire avalanche photodiode with monolithically integrated microlens, for dual-mode passive & active imaging arrays  

NASA Astrophysics Data System (ADS)

There is a growing need in space and environmental research applications for dual-mode, passive and active 2D and 3D ladar imaging methods. To fill this need, an advanced back-illuminated avalanche photodiode (APD) design is presented based on crystallographically etched (100) epitaxial silicon on R-plane sapphire (SOS), enabling single photon sensitive, solid-state focal plane arrays (FPAs) with wide dynamic range, supporting passive and active imaging capability in a single FPA. When (100) silicon is properly etched with KOH:IPA:H2O solution through a thermally grown oxide mask, square based pyramidal frustum or mesa arrays result with the four mesa sidewalls of the APD formed by (111) silicon planes that intersect the (100) planes at a crystallographic angle, ?c = 54.7°. The APD device is fabricated in the mesa using conventional silicon processing technology. Detectors are back-illuminated through light focusing microlenses fabricated in the thinned, AR-coated sapphire substrate. The APDs share a common, front-side anode contact, made locally at the base of each device mesa. A low resistance (Al) or (Cu) metal anode grid fills the space between pixels and also inhibits optical cross-talk. SOS-APD arrays are indium bump-bonded to CMOS readout ICs to produce hybrid FPAs. The quantum efficiency for the square 27 µm pixels exceeds 50% for 250 nm < ? < 400 nm and exceeds 80% for 400 nm < ? < 700 nm. The sapphire microlenses compensate detector quantum efficiency loss resulting from the mesa geometry and yield 100% sensitive-area-fill-factor arrays, limited in size only by the wafer diameter.

Stern, Alvin G.; Cole, Daniel C.

2008-12-01

102

Linear arrays of InGaAs/InP avalanche photodiodes for 1.0-1.7 micron  

NASA Technical Reports Server (NTRS)

Separate absorption and multiplication InGaAs/InP avalanche photodiodes (SAM-APDs) with a floating guard ring structure that is well-suited to array applications have been successfully demonstrated. Individual APDs have breakdown voltages greater than 80 V, multiplications over 40 at 100 nA dark current, and uniform spatial gain profiles. Uniform I-V characteristics and gains have been measured over linear dimensions as large as 1.2 cm. Gains over 10 at low multiplied dark currents were measured on 21 consecutive devices at the wafer level.

Ackley, D. E.; Hladky, J.; Lange, M. J.; Mason, S.; Erickson, G.; Olsen, G. H.; Ban, V. S.; Forrest, S. R.; Staller, C.

1990-01-01

103

Adaptive Detector Arrays for Optical Communications Receivers  

NASA Technical Reports Server (NTRS)

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.

Vilnrotter, V.; Srinivasan, M.

2000-01-01

104

Design and development of multicolor detector arrays  

NASA Astrophysics Data System (ADS)

Multi-color infrared (IR) focal planes are required for high performance sensor applications. These sensors will require multi-color focal plane arrays (FPA) that will cover various wavelengths of interest in MWIR/LWIR and LWIR/VLWIR bands. There has been a significant progress in HgCdTe detector technology for multi-color MWIR/LWIR and LWIR/VLWIR focal plane arrays [1,2,3]. Two-color IR FPA eliminate the complexity of multiple single-color IR FPAs and provide a significant reduction of weight and power in a simpler, reliable and affordable systems. The complexity of multicolor IR detector MWIR/LWIR makes the device optimization by trial and error not only impractical but also merely impossible. Too many different geometrical and physical variables need to be considered at the same time. Additionally material characteristics are only relatively controllable and depend on the process repeatability. In this context the ability of performing simulation experiments where only one or a few parameters are carefully controlled is paramount for a quantum improvement of a new generation of multicolor detectors for various applications. Complex multi-color detector pixels cannot be designed and optimized by using a conventional 1D models. Several additional physical phenomena need to be taken into account. In designing a conventional photovoltaic IR detector array, a trade off exists on the choice of the pixel pitch, the pixel area and its height. The main goal of the device optimization is to reduce the pixel cross talk while keeping a high filling factor and detection efficiency. If the pixel height is made comparable to the lateral pixel dimension the contribution of the lateral photocurrent and lateral generation-recombination current becomes relevant and a full 2D simulation needs to be performed. It also important to point out that the few attempts to perform 2D simulations have reached the conclusion that for advanced IR arrays a full 3D approach should be used. The most challenging aspect of the array design and simulation is the pixel cross-talk effects. Since this is caused by the interaction with the four nearest neighboring pixels, even a description based on a 2D simulation model in most cases is not adequate. It is consequently important to include results from 3D simulation models as a guide to build lower dimensionality models.

Sood, Ashok K.; Egerton, E. James; Puri, Yash R.; Bellotti, Enrico; Becker, Latika S. R.; Balcerak, Raymond S.; Sivananthan, Siva

2004-10-01

105

Development of high-transmittance back-illuminated silicon-on-sapphire substrates thinned below 25 micrometers and bonded to fused silica for high quantum efficiency and high resolution avalanche photodiode imaging arrays  

NASA Astrophysics Data System (ADS)

There is a growing need in scientific and industrial applications for dual-mode, passive and active 2D and 3D LADAR imaging methods. To fill this need, solid-state, single photon sensitive silicon avalanche photodiode (APD) detector arrays offer high sensitivity and the possibility to operate with wide dynamic range in dual linear and Geiger-mode for passive and active imaging. To support the fabrication of large scale, high quantum efficiency and high resolution silicon avalanche photodiode arrays and other advanced solid-state optoelectronics, a novel, high transmittance, backilluminated silicon-on-sapphire substrate has been developed incorporating a single crystal, epitaxially grown aluminum nitride (AlN) antireflective layer between silicon and R-plane sapphire, that provides refractive index matching to improve the optical transmittance into silicon from sapphire. A one quarter wavelength magnesium fluoride antireflective layer deposited on the back-side of the sapphire improves optical transmittance from the ambient into the sapphire. The magnesium fluoride plane of the Si-(AlN)-sapphire substrate is bonded to a fused silica wafer that provides mechanical support, allowing the sapphire to be thinned below 25 micrometers to improve back-illuminated optical transmittance, while suppressing indirect optical crosstalk from APD emitted light undergoing reflections in the sapphire, to enable high quantum efficiency and high resolution detector arrays.

Stern, Alvin G.

2012-03-01

106

Astronomical imaging with infrared array detectors.  

PubMed

History shows that progress in astronomy often stems directly from technological innovation and that each portion of the electromagnetic spectrum offers unique insights into the nature of the universe. Most recently, the widespread availability of infrared-sensitive two-dimensional array detectors has led to dramatic improvements in the capabilities of conventional ground-based observatories. The impact of this new technology on our understanding of a wide variety of phenomena is illustrated here by infrared pictures of star-forming regions, of nebulae produced by the late stages of stellar evolution, of the nucleus of our own galaxy(the Milky Way), and of activity in other galaxies. PMID:17817072

Gatley, I; Depoy, D L; Fowler, A M

1988-12-01

107

SWIR to LWIR HDVIP HgCdTe detector array performance  

NASA Astrophysics Data System (ADS)

DRS uses LPE-grown SWIR, MWIR and LWIR HgCdTe material to fabricate High-Density Vertically Integrated Photodiode (HDVIP) architecture detectors. 2.5 ?m, 5.3 ?m and 10.5 ?m cutoff detectors have been fabricated into linear arrays as technology demonstrations targeting remote sensing programs. This paper presents 320 x 6 array configuration technology demonstrations' performance of HDVIP HgCdTe detectors and single detector noise data. The single detector data are acquired from within the 320 x 6 array. Within the arrays, the detector size is 40 ?m x 50 ?m. The MWIR detector array has a mean quantum efficiency of 89.2% with a standard deviation to mean ratio, ?/? = 1.51%. The integration time for the focal plane array (FPA) measurements is 1.76 ms with a frame rate of 557.7 Hz. Operability values exceeding 99.5% have been obtained. The LWIR arrays measured at 60 K had high operability with only ~ 3% of the detectors having out of family response. Using the best detector select (BDS) feature in the read out integrated circuit (ROIC), a feature that picks out the best detector in every row of six detectors, a 320 x 1 array with 100% operability is obtained. For the 320 x 1 array constituted using the BDS feature, a 100% operable LWIR array with average NEI value of 1.94 x 10 11 ph/cm 2/s at a flux of 7.0 x 10 14 ph/cm2/s has been demonstrated. Noise was measured at 60 K and 50 mV reverse bias on a column of 320 diodes from a 320 x 6 LWIR array. Integration time for the measurement was 1.76 ms. Output voltage for the detectors was sampled every 100 th frame. 32,768 frames of time series data were collected for a total record length of 98 minutes. The frame average for a number of detectors was subtracted from each detector to correct for temperature drift and any common-mode noise. The corrected time series data was Fourier transformed to obtain the noise spectral density as a function of frequency. Since the total time for collecting the 32,768 time data series points is 98.0 minutes, the minimum frequency is 170 ?Hz. A least squares fit of the form (A/f + B) is made to the noise spectral density data to extract coefficients A and B that relate to the 1/f and white noise of the detector respectively. In addition noise measurements were also acquired on columns of SWIR detectors. Measurements were made under illuminated conditions at 4 mV and 50 mV reverse bias and under dark conditions at 50 mV reverse bias. The total collection time for the SWIR detectors was 47.7 minutes. The detectors are white noise limited down to ~10 mHz under dark conditions and down to ~ 100 mHz under illuminated conditions.

D'Souza, A. I.; Stapelbroek, M. G.; Dawson, L.; Ely, P.; Yoneyama, C.; Reekstin, J.; Skokan, M. R.; Kinch, M. A.; Liao, P. K.; Ohlson, M. J.; Ronci, P. J.; Teherani, T.; Shih, H. D.; Robinson, J.

2006-05-01

108

Infrared array detectors for the United Kingdom Infrared Telescope (UKIRT)  

NASA Astrophysics Data System (ADS)

The impact on ground-based IR astronomy of the new generation of infrared detector arrays which incorporate charge storage and multiplexed readout schemes on the focal plane array itself is considered. Plans for proposed instrumentation for UKIRT which will use such detector arrays are outlined. The new instruments will include a 1 - 5 ?m area mapping photometer and a low resolution 1 - 5 ?m cooled grating spectrometer. Preliminary work on the evaluation of certain types of arrays is described.

McLean, I. S.; Wade, R.

1984-01-01

109

Contactless conductivity detector array for capillary electrophoresis.  

PubMed

A CE system featuring an array of 16 contactless conductivity detectors was constructed. The detectors were arranged along 70 cm length of a capillary with 100 cm total length and allow the monitoring of separation processes. As the detectors cannot be accommodated on a conventional commercial instrument, a purpose built set-up employing a sequential injection manifold had to be employed for automation of the fluid handling. Conductivity measurements can be considered universal for electrophoresis and thus any changes in ionic composition can be monitored. The progress of the separation of Na(+) and K(+) is demonstrated. The potential of the system to the study of processes in CZE is shown in two examples. The first demonstrates the differences in the developments of peaks originating from a sample plug with a purely aqueous background to that of a plug containing the analyte ions in the buffer. The second example visualizes the opposite migration of cations and anions from a sample plug that had been placed in the middle of the capillary. PMID:24285496

Stojkovic, Marko; Koenka, Israel Joel; Thormann, Wolfgang; Hauser, Peter C

2014-02-01

110

The Trace Analysis of DEET in Water using an On-line Preconcentration Column and Liquid Chromatography with UV Photodiode Array Detection  

EPA Science Inventory

A method for the detection of trace levels of N,N-diethyl-m-toluamide (DEET) in water is discussed. The method utilizes an on-line preconcentration column in series with high performance liquid chromatography (HPLC) and UV photodiode array detection. DEET, a common insect repel...

111

Microfluidic Biosensor Array with Integrated Poly(2,7-Carbazole)/Fullerene-Based Photodiodes for Rapid Multiplexed Detection of Pathogens  

PubMed Central

A multiplexed microfluidic biosensor made of poly(methylmethacrylate) (PMMA) was integrated into an array of organic blend heterojunction photodiodes (OPDs) for chemiluminescent detection of pathogens. Waterborne Escherichia coli O157:H7, Campylobacter jejuni and adenovirus were targeted in the PMMA chip, and detection of captured pathogens was conducted by poly(2,7-carbazole)/fullerene OPDs which showed a responsivity over 0.20 A/W at 425 nm. The limits of chemiluminescent detection were 5 × 105 cells/mL for E. coli, 1 × 105 cells/mL for C. jejuni, and 1 × 10?8 mg/mL for adenovirus. Parallel analysis for all three analytes in less than 35 min was demonstrated. Further recovery tests illustrated the potential of the integrated biosensor for detecting bacteria in real water samples. PMID:24287522

Pires, Nuno Miguel Matos; Dong, Tao

2013-01-01

112

Microfluidic biosensor array with integrated poly(2,7-carbazole)/fullerene-based photodiodes for rapid multiplexed detection of pathogens.  

PubMed

A multiplexed microfluidic biosensor made of poly(methylmethacrylate) (PMMA) was integrated into an array of organic blend heterojunction photodiodes (OPDs) for chemiluminescent detection of pathogens. Waterborne Escherichia coli O157:H7, Campylobacter jejuni and adenovirus were targeted in the PMMA chip, and detection of captured pathogens was conducted by poly(2,7-carbazole)/fullerene OPDs which showed a responsivity over 0.20 A/W at 425 nm. The limits of chemiluminescent detection were 5 × 10(5) cells/mL for E. coli, 1 × 10(5) cells/mL for C. jejuni, and 1 × 10(-8) mg/mL for adenovirus. Parallel analysis for all three analytes in less than 35 min was demonstrated. Further recovery tests illustrated the potential of the integrated biosensor for detecting bacteria in real water samples. PMID:24287522

Matos Pires, Nuno Miguel; Dong, Tao

2013-01-01

113

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

114

Organic non-volatile resistive photo-switches for flexible image detector arrays.  

PubMed

A unique implementation of an organic image detector using resistive photo-switchable pixels is presented. This resistive photo-switch comprises the vertical integration of an organic photodiode and an organic resistive switching memory element. The photodiodes act as a photosensitive element while the resistive switching elements simultaneously store the detected light information. PMID:25534514

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

2015-02-01

115

Energy resolution of scintillation detectors readout with large area avalanche photodiodes and photomultipliers  

Microsoft Academic Search

The energy resolution of small NaI(Tl), CsI(Tl), BGO, GSO, YAP and LSO crystals has been studied using 16 mm diameter large area avalanche photodiodes (LAAPD) and a 52 mm diameter photomultiplier. The best result of 4.8% for 662 keV ?-rays from a 137Cs source was obtained with a 9 mm in diameter by 9 mm high CsI(Tl) scintillator coupled to

M. Moszynski; M. Kapusta; D. Wolski; M. Szawlowski; W. Klamra

1998-01-01

116

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

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

117

Sixteen-element Ge-on-SOI PIN photo-detector arrays for parallel optical interconnects  

NASA Astrophysics Data System (ADS)

We describe the structure and testing of one-dimensional array parallel-optics photo-detectors with 16 photodiodes of which each diode operates up to 8 Gb/s. The single element is vertical and top illuminated 30-?m-diameter silicon on insulator (Ge-on-SOI) PIN photodetector. High-quality Ge absorption layer is epitaxially grown on SOI substrate by the ultra-high vacuum chemical vapor deposition (UHV-CVD). The photodiode exhibits a good responsivity of 0.20 A/W at a wavelength of 1550 nm. The dark current is as low as 0.36 ?A at a reverse bias of 1 V, and the corresponding current density is about 51 mA/cm2. The detector with a diameter of 30 ?m is measured at an incident light of 1.55 ?m and 0.5 mW, and the 3-dB bandwidth is 7.39 GHz without bias and 13.9 GHz at a reverse bias of 3 V. The 16 devices show a good consistency.

Li, Chong; Xue, Chun-Lai; Liu, Zhi; Cheng, Bu-Wen; Wang, Qi-Ming

2014-03-01

118

Fabrication of pop-up detector arrays on Si wafers  

NASA Astrophysics Data System (ADS)

High sensitivity is a basic requirement for a new generation of thermal detectors. To meet the requirement, close-packed, 2D 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 IR 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 1 micrometers 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 2D 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 fabrication techniques, including photolithography, anisotropic chemical etching, reactive-ion etching, and laser dicing, we have fabricated PUD detector arrays of fourteen designs with a variation of four parameters including cantilever length, torsion bar length and width, and leg length. Folding test 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 thermistor and heaters on the pop-up detectors is under way, preparing us for the next step of the experiment, the thermal test.

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

1999-08-01

119

Fabrication of Pop-up Detector Arrays on Si Wafers  

NASA Technical Reports Server (NTRS)

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, preparing us for the next step of the experiment, the thermal test.

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

1999-01-01

120

Multiwavelength infrared focal plane array detector  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

121

A multivariate study of the performance of an ultrasound-assisted madder dyes extraction and characterization by liquid chromatography-photodiode array detection.  

PubMed

An extraction method of madder (Rubia tinctorum) roots dyes is established and optimized to obtain the original chemical composition. A central composite design (CCD) was developed to specify the importance of the three major factors studied (time, temperature and solvent composition) affecting the ultrasound-assisted extraction of this matrix. A preliminary granulometric study of madder roots is realized in the aim to determine the optimal particles size corresponding to the best ultrasound effects. A comparison with the classical extraction method of madder dyes by reflux is described. The identification of the constituents of R. tinctorum is carried out by liquid chromatography coupled with a photodiode array detector (LC-PDA). Anthraquinonic aglycone and heterosidic dyes compounds are characterized by retention time and UV spectrum: alizarin (1,2-dihydroxyanthraquinone), purpurin (1,2,4-trihydroxyanthraquinone), lucidin (1,3-dihydroxy-2-hydroxymethylanthraquinone), rubiadin (1,3-dihydroxy-2-methylanthraquinone), xanthopurpurin (1,3-dihydroxyanthraquinone), pseudopurpurin (1,2,4-trihydroxy-3-carboxyanthraquinone), lucidin primeveroside, ruberythric acid (alizarin primeveroside), galiosin (pseudopurpurin primeveroside) and rubiadin primeveroside. The optimal experimental conditions are 18min, 36 degrees C and 37/63 MeOH/H(2)O (v/v). PMID:18617432

Cuoco, Guillaume; Mathe, Carole; Archier, Paul; Chemat, Farid; Vieillescazes, Cathy

2009-01-01

122

Performance characteristics of multi-anode microchannel array detector systems  

NASA Technical Reports Server (NTRS)

The multi-anode microchannel arrays (MAMAs) are state-of-the-art, pulse-counting, photoelectric array detectors designed specifically for use in space astrophysics instruments. The present paper provides a description of recent progress related to the development of ultraviolet and visible-light versions of the MAMA detectors, taking into account a comparison of the operating characteristics of these devices with those of photoconductive array detectors, such as the CCDs. Attention is given to MAMA detector system design parameters, the operating characteristics of MAMAs and CCDs, MAMA performance characteristics, and future developments.

Timothy, J. G.

1984-01-01

123

Achieving a Linear Dose Rate Response in Pulse-Mode Silicon Photodiode Scintillation Detectors Over a Wide Range of Excitations  

NASA Astrophysics Data System (ADS)

We are developing a new dose calibrator for nuclear pharmacies that can measure radioactivity in a vial or syringe without handling it directly or removing it from its transport shield “pig”. The calibrator's detector comprises twin opposing scintillating crystals coupled to Si photodiodes and current-amplifying trans-resistance amplifiers. Such a scheme is inherently linear with respect to dose rate over a wide range of radiation intensities, but accuracy at low activity levels may be impaired, beyond the effects of meager photon statistics, by baseline fluctuation and drift inevitably present in high-gain, current-mode photodiode amplifiers. The work described here is motivated by our desire to enhance accuracy at low excitations while maintaining linearity at high excitations. Thus, we are also evaluating a novel “pulse-mode” analog signal processing scheme that employs a linear threshold discriminator to virtually eliminate baseline fluctuation and drift. We will show the results of a side-by-side comparison of current-mode versus pulse-mode signal processing schemes, including perturbing factors affecting linearity and accuracy at very low and very high excitations. Bench testing over a wide range of excitations is done using a Poisson random pulse generator plus an LED light source to simulate excitations up to ˜106 detected counts per second without the need to handle and store large amounts of radioactive material.

Carroll, Lewis

2014-02-01

124

Development of a Validated HPLC/Photodiode Array Method for the Determination of Isomenthone in the Aerial Parts of Ziziphora tenuior L.  

PubMed Central

Background Ziziphora tenuior L. known as Kakuti in Persian, is used in traditional medicine for fever, dysentery, uterus infection and as an analgesic. It is used also in the treatment of gastrointestinal disorders as carminative, or remedy of diarrhea or nausea. Major components of plant essential oil including pulegone, isomenthone, thymol, menthone, and piperitone are suggested to be responsible for the mentioned medicinal properties. Objectives In the present study, a normal high performance liquid chromatography (HPLC)/photodiode array validated method for quantification of isomenthone, one of the major constituents of Ziziphora, was established for the first time with a simple, rapid and accurate method. Materials and Methods HPLC analysis was done on a Waters system, equipped with 515 HPLC pump and waters 2996 photodiode array detector. The column was a Nova-Pak Silica (3.9 × 150 mm), and Empower software was used for the determination of the compounds and processing the data. The method was validated according to USP 32 requirements. Results A selective method for the resolution of isomenthone from two nearest peaks, thymol, and carvacrol was obtained with gradient system of hexane (A), and hexane: ethyl acetate (9:1) (B), starting with A: B (100:0) for 2 minutes, then 0?20% B in 5 minutes, A:B (80:20) for 5 minutes, then 20-30% B in 3 minutes, 30-100% B for 5 minutes, A:B (0:100) for 4 minutes following with equilibrating for 10 minutes. The flow rate was 1 mL/min at 22?C and the injection volume for the standards and the samples was 20 ?L. The retention time for isomenthone was found to be 7.45 minutes. The regression equation was y = 143235x - 2433 with the correlation co-factor R2 = 0.9992 and the percent recovery of 65.4 ± 3.85%. The sample obtained from 5 g of Z. teniour dried powder in 6 mL extract was standardized to contain 1.14 ± 0.030 ?L/mL isomenthone which is equivalent to % 1.37 ?L/g of the dried powdered plant. Limit of detection (LOD) and Limit of Quantification (LOQ) were 0.037, and 0.122 µL/mL determined by using the formula based on the signal to noise ratio. Conclusions Due to this fact that plant extracts may cause irreversible damages to the capillary GC columns, using validated HPLC method for the analysis of these compounds in cruse plant extracts is recommended. PMID:24624211

Ghassemi, Nasrollah; Ghanadian, Mustafa; Ghaemmaghami, Lili; Kiani, Haran

2013-01-01

125

Spada: An Array of Spad Detectors For Astrophysical Applications  

Microsoft Academic Search

Astrophysical studies require accurate, sensitive and fast detectors to detect faint sources with high variability. Recently an array of Single Photon Avalanche Diodes (SPAD), SPADA, has been developed. This array is suitable for competitive adaptive optics operations and fast transient image acquisition at a fraction of the current cost of imaging arrays. The fabricated solid-state photon counters are rugged, easily

Giovanni Bonanno; Massimiliano Belluso; Franco Zappa; Simone Tisa; Sergio Cova; Piera Maccagnani; Domenico Bonaccini Calia; Roberto Saletti; Roberto Roncella; Sergio Billotta

2005-01-01

126

Multianode microchannel array detectors for Space Shuttle imaging applications  

NASA Technical Reports Server (NTRS)

The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric, photoncounting array detectors that have been developed and qualified specifically for use in space. MAMA detectors with formats as large as 256 x 1024 pixels are now in use or under construction for a variety of imaging and tracking applications. These photo-emissive detectors can be operated in a windowless configuration at extreme ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. The construction and modes-of-operation of the MAMA detectors are briefly described and the scientific objectives of a number of sounding rocket and Space Shuttle instruments utilizing these detectors are outlined. Performance characteristics of the MAMA detectors that are of fundamental importance for operation in the Space Shuttle environment are described and compared with those of the photo-conductive array detectors such as the CCDs and CIDs.

Timothy, J. G.; Bybee, R. L.

1981-01-01

127

Triangular-barrier quantum rod photodiodes: Their fabrication and detector characteristics  

SciTech Connect

We have fabricated a GaAs-based triangular-barrier photodiode, in which self-assembled InGaAs quantum rods (Q-rods) are embedded in its barrier region. Transport study at 100?K has shown that electrons start to flow mainly through Q-rods when a bias is set above a threshold. Upon illumination, photo-generated holes are found to accumulate in the middle portion of Q-rods and efficiently lower the local barrier height, yielding the responsivity as high as 10{sup 5}?A/W at the incident light of 1 fW.

Ohmori, M.; Kobayashi, Y.; Vitushinskiy, P.; Nakamura, S.; Kojima, T.; Sakaki, H. [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-0034 (Japan)

2014-02-24

128

Design and testing of an active quenching circuit for an avalanche photodiode photon detector  

NASA Technical Reports Server (NTRS)

The photon-detection capabilities of avalanche photodiodes (APDs) operating above their theoretical breakdown voltages are described, with particular attention given to the needs and methods of quenching an avalanche once breakdown has occurred. A brief background on the motives of and previous work with this mode of operation is presented. Finally, a description of the design and testing of an active quenching circuit is given. Although the active quenching circuit did not perform as expected, knowledge was gained as to the signal amplitudes necessary for quenching and the need for a better model for the above-breakdown circuit characteristics of the Geiger-mode APD.

Arbel, D.; Schwartz, J. A.

1991-01-01

129

An accurate and reproducible method for the quantitative analysis of isoflavones and their metabolites in rat plasma using liquid chromatography/mass spectrometry combined with photodiode array detection.  

PubMed

To study the safety and potential health benefits of soy isoflavones, a rapid and simple method based on liquid chromatography combined with mass spectrometry (LC/MS) and photodiode array detector (PDA) was developed for the determination of isoflavones in rat plasma. The analytes included daidzein, genistein, glycitein, equol, 4-ethyl phenol, and biochanin A over a concentration range of 1.0-4320.0 nM using 75 microL of rat plasma. Rat plasma samples were hydrolyzed by adding an enzyme mixture from Helix pomatia containing glucuronidase and sulfatase to convert the isoflavone beta-glycosides daidzin, genistin, and glycitin to their active aglycone forms. A liquid-liquid extraction method using ethyl acetate as the extraction solvent was used to extract aglycones and the internal standards (phenolphthalein beta-D glucuronide, 4-methylumbelliferyl sulfate, and apigenin) from digested plasma samples. The extract was evaporated to dryness under a nitrogen stream, reconstituted with 0.1% formic acid in water-acetonitrile (85 + 15), and injected into a Zorbax SB-CN reversed-phase column (4.6 x 75 mm, 3.5 microm particle size). The Micromass ZQ detector was operated in the positive ion selected-ion monitoring mode. The flow rate for LC was 1.0 mL/min, with a split where 25% of the effluent was introduced into the electrospray ionization probe of the MS instrument and 75% into the PDA. The chromatographic run time was 16.0 min, with delay of 10 min/injection. The interday precision and accuracy of the standard samples were <2.6% relative standard deviation and <10% relative error, respectively. Recovery of the reported isoflavones with this method varied from 86 to 100%. PMID:16915859

Sepehr, Estatira; Robertson, Patrick; Gilani, G Sarwar; Cooke, Gerard; Lau, Benjamin Pui-Yan

2006-01-01

130

A low noise infrared spot scanner for testing detector arrays  

NASA Technical Reports Server (NTRS)

A low noise spot scanner has been built for use in testing the performance of infrared detector arrays for NASA's IR detector technology development program and the University of California's MICRO program. The scanner provides a convenient low noise detector test environment and a wide range of test conditions including versatile temperature control of the detector, ambient background, and blackbody source temperature and control of spot size, color, and brightness.

Puetter, R. C.; Brissenden, P.; Casler, J.; Hier, R. G.; Jones, B.

1984-01-01

131

Recent advances in avalanche photodiode technology  

NASA Astrophysics Data System (ADS)

Avalanche photodiodes (APDs) are solid state devices having an internal signal gain which gives them a better signal-to-noise ratio than standard photodiodes. Although they have been studied for years, recent advances in the fabrication techniques have allowed the construction of multielement arrays (up to 10 X 10) with high performance capability. This progress has resulted in increased potential for exploiting the advantages of APDs in a variety of important applications including measurements requiring fast response such as nuclear and high energy physics research, industrial nondestructive testing, medical instrumentation, and biomedical research using low energy particles. Recent experimental data characterizing APDs and APD arrays used as x-ray, particle, and low level light detectors are presented.

Squillante, Michael R.; Gordon, Jeffrey S.; Farrell, Richard; Vasile, Stefan A.; Daley, Kathleen; Oakes, Carlton E.; Vanderpuye, K.

1993-12-01

132

Evaluation of Hydrogenated Amorphous Silicon Photodiodes and Field-Effect Transistors for Use as Elements of Two - X-Ray Imaging Arrays.  

NASA Astrophysics Data System (ADS)

Imaging arrays fabricated from hydrogenated amorphous silicon (a-Si:H) have shown great potential for application in radiotherapy and diagnostic x-ray imaging. One particular design of array under development consists of a regular two-dimensional pattern of pixels, each pixel comprised of an a-Si:H photodiode, which indirectly detects the incident x-ray flux, and an a-Si:H field-effect transistor (FET), which allows readout of the charge information stored in the photodiode. Present-day arrays of this design allow real-time, digital x-ray imaging over a large area (i.e., 25 x 25 cm) with resolution as high as ~ 100 mum. A useful component in the development of such a-Si:H arrays is characterization of the properties of the individual devices which make up the arrays, namely the a-Si:H photodiode and FET. Device characterization helps determine the degree to which the arrays are viable for x-ray imaging applications and also enables optimization of array design and operation. In this thesis, measurements of the noise and radiation-damage properties of a-Si:H photodiodes and FETs are presented. Measurements were performed for devices of various design operated at voltages similar to those anticipated for array operation. For the noise properties, current-noise-power spectral density measurements were carried out. Such measurements enabled prediction of device spectral noise levels for arrays of various design and operational parameters. For the radiation-damage measurements, device signal and noise properties were examined as a function of dose using a ^{60}Co (~1.25 MeV) source to maximum cumulative doses of ~2 times 10^4 Gy. Annealing of device properties affected by the radiation was also examined. It was generally concluded from the radiation-damage measurements that the devices exhibited the necessary radiation tolerance for x-ray imaging applications. In addition to the noise and radiation-damage measurements, a noise model for predicting the lower noise limit of an a-Si:H array is detailed. The model uses results from the device spectral noise measurements and predicts that for most x-ray imaging applications FET thermal noise will be the dominant noise source.

Boudry, John Moore

133

Determination of saffron (Crocus sativus L.) components in crude plant extract using high-performance liquid chromatography-UV-visible photodiode-array detection-mass spectrometry.  

PubMed

The determination of saffron components in crude plant extracts by high-performance liquid chromatography-UV-visible photodiode-array detection on-line with mass spectrometry is described. The method is shown to be suitable for the determination of picrocrocin, the glycosidic precursor of safranal, safranal and flavonoids; it is the technique of choice for the analysis of crocetin glycosides (crocins) carrying one up to five glucoses and differentiation of their trans and cis isomers. PMID:7757208

Tarantilis, P A; Tsoupras, G; Polissiou, M

1995-05-01

134

Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection  

Microsoft Academic Search

A high-performance liquid chromatographic (HPLC) separation method with photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained after acid hydrolysis of freeze-dried food material. Identification was based on retention time, UV and mass spectra by comparison with commercial standards,

Ulla Justesen; Pia Knuthsen; Torben Leth

1998-01-01

135

Determination of saffron ( Crocus sativus L.) components in crude plant extract using high-performance liquid chromatography-UV-visible photodiode-array detection-mass spectrometry  

Microsoft Academic Search

The determination of saffron components in crude plant extracts by high-performance liquid chromatography -UV-visible photodiode-array detection on-line with mass spectrometry is described. The method is shown to be suitable for the determination of picrocrocin, the glycosidic precursor of safranal, safranal and flavonoids; it is the technique of choice for the analysis of crocetin glycosides (crocins) carrying one up to five

Petros A. Tarantilis; George Tsoupras; Moschos Polissiou

1995-01-01

136

Automated on-line liquid chromatography–photodiode array–mass spectrometry method with dilution line for the determination of bisphenol A and 4-octylphenol in serum  

Microsoft Academic Search

A novel on-line liquid chromatography–photodiode array detection–mass spectrometry (LC–DAD–MS) system was established with restricted-access media (RAM) pre-column and dilution line combined with a column-switching valve. The serum samples were injected directly onto pre-column under diluted condition by dilution line. After elution of proteins in the serum, the analytes were backflushed onto an ODS analytical column using a six-port column-switching device.

Min Liu; Yuki Hashi; Fengyun Pan; Jianguo Yao; Guanqun Song; Jin-Ming Lin

2006-01-01

137

Development of 58 x 62 Si:Sb detector arrays  

NASA Technical Reports Server (NTRS)

The fabrication of antimony doped silicon (Si:Sb) detector arrays are described for use in 30 micron infrared imaging applications. The operation of the multiplexer readout circuit which will be used for this application is also described.

Worley, S.; Gaalema, S.

1986-01-01

138

Particle Identification in the NIMROD-ISiS Detector Array  

SciTech Connect

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.

Wuenschel, S.; Hagel, K.; May, L. W.; Wada, R.; Yennello, S. J. [Texas A and M University Cyclotron Institute College Station TX 77843 (United States)

2009-03-10

139

Particle Identification in the NIMROD-ISiS Detector Array  

E-print Network

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 86Kr+64Ni at 35MeV/u.

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

2009-03-04

140

Particle Identification in the NIMROD-ISiS Detector Array  

NASA Astrophysics Data System (ADS)

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? array is described. Performance of the detectors and the analysis method are presented for the reaction of 86Kr+64Ni at 35 MeV/u.

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

2009-03-01

141

Shot-noise-limited laser power stabilization with a high-power photodiode array.  

PubMed

The output power of a cw Nd:YAG laser was stabilized in a dc-coupled feedback loop with a low-noise multiphotodiode detector and an electro-optic amplitude modulator in the frequency band from 1 Hz to 1 kHz. For the first time, to our knowledge, an independently measured relative power noise of 2.4 x 10(-9) Hz(-1/2) at 10 Hz was achieved, fulfilling the power stability requirements of the Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) gravitational wave detector. PMID:19794765

Kwee, Patrick; Willke, Benno; Danzmann, Karsten

2009-10-01

142

A Research on CdZnTe Array Detector  

NASA Astrophysics Data System (ADS)

The CdZnTe array detector is a new type of semiconductor detector, and it has been developing rapidly in recent years. It has some characteristics of high spatial resolution, high energy resolution, and it can work at room temperature. This article describes the physical characteristics and the working principle of the CdZnTe detector. It also introduces the production process of the CdZnTe array detector, including the pretreatment of the chips, passivation, ohmic electrode production, array template selection, and array package process selection (micro-interconnect). For evaluating the performance of the detector, the authors produced a 4 pixel × 4 pixel CdZnTe array and an 8 pixel × 8 pixel CdZnTe array (The thicknesses are 5 mm and 2 mm, respectively.The pixel size is 2 mm × 2 mm. The gaps are 0.15 mm and 0.2 mm, respectively.) with cooperation partner successfully. A multi-channel electronic readout system based on the ASIC (Application Specific Integrated Circuit) chip is used for the charge measurement of the 4 pixel × 4 pixel array of CdZnTe. The 16-pixel spectrum and the corresponding energy resolution are obtained with the ^{137}Cs radiation source. Among the results of each pixel, the best resolution is 4.8%@662 keV.

Cai, M. S.; Guo, J. H.; Xie, M. G.; Zheng, C. X.

2013-09-01

143

Study of flavonoids of Sechium edule (Jacq) Swartz (Cucurbitaceae) different edible organs by liquid chromatography photodiode array mass spectrometry.  

PubMed

A liquid chromatography-mass spectrometry (LC-MS)-based method was developed for the characterization of flavonoids from Sechium edule (Jacq) Swartz (Cucurbitaceae) edible organs, a plant cultivated since pre-Colombian times in Mexico where the fruit is called chayote. Chayote is used for human consumption in many countries; in addition to the fruits, stems, leaves and the tuberous part of the roots are also eaten. Eight flavonoids, including three C-glycosyl and five O-glycosyl flavones, were detected, characterized by nuclear magnetic resonance spectroscopic data, and quantified in roots, leaves, stems, and fruits of the plant by LC-photodiode array-MS. The aglycone moieties are represented by apigenin and luteolin, while the sugar units are glucose, apiose, and rhamnose. The results indicated that the highest total amount of flavonoids was in the leaves (35.0 mg/10 g of dried part), followed by roots (30.5 mg/10 g), and finally by stems (19.3 mg/10 g). PMID:15479015

Siciliano, Tiziana; De Tommasi, Nunziatina; Morelli, Ivano; Braca, Alessandra

2004-10-20

144

Charge Transport in Arrays of Semiconductor Gamma-Ray Detectors  

Microsoft Academic Search

We analyze the effects of electrode size on performance of arrays of semiconductor gamma-ray detectors, especially when there is significant charge trapping. With large electrodes, motions of holes and electrons are of equal importance, but when the positive electrode is segmented into an array of small elements the contributions of holes to the output, and hence the effects of hole

H. H. Barrett; J. D. Eskin; H. B. Barber

1995-01-01

145

Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging  

NASA Astrophysics Data System (ADS)

A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans.

El-Ghussein, Fadi; Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.

2014-01-01

146

Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging  

PubMed Central

Abstract. A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans. PMID:23979460

El-Ghussein, Fadi; Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.

2013-01-01

147

Turntable Wide Band Infrared Detector Array for Space Situational Awareness  

Microsoft Academic Search

The Center for High Technology Materials at the University of New Mexico has been investigating tunable quantum well\\/dot detectors for infrared detection. These devices have been manufactured in 300 x 256 pixel arrays and can be adjusted to obtain a maximum responsivity to wavelengths ranging from 1 mm to 10 mm by applying an external bias voltage. This detector has

J. Andrews; S. Restaino; S. Teare; S. Krishna; C. Wilcox; T. Martinez

2007-01-01

148

APPLICATIONS OF LASERS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Determination of the spatial characteristics of the radiation emitted by pulsed ultraviolet lasers using a photodiode array  

NASA Astrophysics Data System (ADS)

An MF-14 photodiode array was used to determine the radiation field of pulsed ultraviolet lasers. The responsivity of this array at the wavelength of 0.337 ?m was S = 4 × 108 V/J. The distributions of the radiation from an N2 laser were determined in the near-field zone. The distributions were also obtained for XeF, XeCl, and KrF excimer lasers in the far-field zone. The angular dimensions of the distributions were determined.

Gorbachev, V. M.; Gorokhov, V. V.; Kalutski?, A. V.; Karelin, V. I.; Korolev, V. N.; Smerdov, V. I.

1992-09-01

149

Continuum-source graphite-furnace atomic absorption spectrometry with photodiode array detection  

NASA Astrophysics Data System (ADS)

A recently developed graphite-furnace continuum-source atomic absorption spectrometer is described and evaluated. For single-element determinations, the system provides detection limits equal to or better than those reported for commercial hollow cathode lamp instruments employing Zeeman background correction at wavelengths as low as 213 nm (Zn). Furthermore, using a fixed atomization cycle and constant detector parameters, simultaneous multielement determinations can be performed for metals having absorption lines falling within a 10 nm spectral window. Detection limits in this case are within a factor of 2 of those reported for single-element determinations. For most metals, detection limits are at least a factor of 2 times better than those previously reported for continuum-source atomic absorption spectrometers. The limiting source of noise for the system is detector readout noise at wavelengths below 240 nm, and signal shot noise at wavelengths above 250 nm.

Fernando, Reshan; Jones, Bradley T.

1994-06-01

150

A Study on the CdZnTe Array Detector  

NASA Astrophysics Data System (ADS)

The CdZnTe array detector is a new type of semiconductor detector being rapidly developed in recent years. It possesses a high spatial resolution and a high energy resolution, and it can work at room temperatures. This paper describes the physical properties and working principle of the CdZnTe array detector, as well as the manufacturing technology, including the chip pretreatment, passivation, ohmic electrode preparation, array template selection, and array packaging technology (micro-interconnection). For evaluating the perfor-mance of the detector, the authors have developed successfully a 4 pixel×4 pixel CdZnTe array and an 8 pixel×8 pixel CdZnTe array (with the thicknesses of 5 mm and 2 mm, the pixel size of 2 mm×2 mm, and the gaps of 0.15 mm and 0.2 mm, respectively) in cooperation with the partner. A multi-channel electronic readout system based on the ASIC (Application Specific Integrated Circuit) chip is devel-oped independently for the charge measurement of the 4 pixel×4 pixel CdZnTe array. The energy spectra and corresponding energy resolutions of the 16 pixels are obtained with the 137Cs radiative source, among them the best resolution is 4.8%@662 kev.

Cai, Ming-sheng; Guo, Jian-hua; Xie, Ming-gang; Zheng, Chun-xiao

2014-04-01

151

Microwave detector response of the Josephson junction arrays  

SciTech Connect

This paper reports on microwave detector response {eta} for three types of superconducting structures:single edge-type Josephson junction, array of series connected junctions and array of RF series and DC parallel connected junctions investigated in the frequency range 35-120 GHz. Experimental dependence of {eta} vs biasing voltage is mainly determined by the interaction of junctions in array. The Selective response, that means narrow linewidth of Josephson radiation, has been observed for third type of superconducting structures in small magnetic field changing the phase shift between near placed junctions. These arrays have the advantage in coupling with the external microwave system.

Ovsyannikov, G.A.; Babayan, G.E. (Inst. of Radio Engineering and Electronics, Academy of Sciences, Moscow 103907 (SU)); Laptev, V.N.; Makhov, V.I. (Research Inst. of Physical Problems, Moscow 103460 (SU))

1991-03-01

152

High responsivity and wide bandwidth operation of InP-based pin-photodiode array monolithically integrated with 90° hybrid using butt-joint regrowth  

NASA Astrophysics Data System (ADS)

The InP-based pin-photodiode array monolithically integrated with a 90° hybrid consisting of multimode interference structures was fabricated using the butt-joint regrowth for compact 100 Gbps coherent receivers. The low dark current of less than 0.2 nA was obtained with InP passivation effect through the selective regrowth process in four-channel photodiodes. A responsivity including total loss of 8.3 dB in the waveguide was as high as 0.14 A/W. The wide 3 dB bandwidth of 24 GHz at a low reverse bias voltage of 1.6 V was also achieved under high optical input power conditions (photocurrent: 4 mA).

Yagi, Hideki; Inoue, Naoko; Masuyama, Ryuji; Katsuyama, Tomokazu; Kikuchi, Takehiko; Onishi, Yutaka; Yoneda, Yoshihiro; Shoji, Hajime

2014-02-01

153

Beam profile monitor for the NSLS vuv ring employing linear photodiode arrays  

SciTech Connect

Among the most important parameters of a storage accelerator are the position and size of the particle beam. In an electron machine, these parameters can be derived from measurements of the emitted synchrotron radiation. We discuss a system which monitors the two-dimensional profile of the synchrotron light in the NSLS vuv ring using commercially available high-resolution linear photosensitive diode arrays. The optical system has been designed to match the size of the image space to the dimensions of the diode sensor area. The scanning rate is automatically adjusted to hold the peaks of the profiles constant over a wide range of beam intensity variations. Video signals from the diode sensors can be readily interfaced to a computer for beam diagnostic purposes. Optics and factors determining the overall resolution of the system are discussed. Preliminary results of beam observations are presented.

Nawrocky, R.J.; Galayda, J.; Yu, L.H.; Shu, D.M.

1985-01-01

154

A diffuse reflectance spectral imaging system for tumor margin assessment using custom annular photodiode arrays  

PubMed Central

Diffuse reflectance spectroscopy (DRS) is a well-established method to quantitatively distinguish between benign and cancerous tissue for tumor margin assessment. Current multipixel DRS margin assessment tools are bulky fiber-based probes that have limited scalability. Reported herein is a new approach to multipixel DRS probe design, which utilizes direct detection of the DRS signal by using optimized custom photodetectors in direct contact with the tissue. This first fiberless DRS imaging system for tumor margin assessment consists of a 4 × 4 array of annular silicon photodetectors and a constrained free-space light delivery tube optimized to deliver light across a 256 mm2 imaging area. This system has 4.5 mm spatial resolution. The signal-to-noise ratio measured for normal and malignant breast tissue-mimicking phantoms was 35 dB to 45 dB for ? = 470 nm to 600 nm. PMID:23243571

Dhar, Sulochana; Lo, Justin Y.; Palmer, Gregory M.; Brooke, Martin A.; Nichols, Brandon S.; Yu, Bing; Ramanujam, Nirmala; Jokerst, Nan M.

2012-01-01

155

Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration  

SciTech Connect

Waveform correlation detectors compare a signal template with successive windows of a continuous data stream and report a detection when the correlation coefficient, or some comparable detection statistic, exceeds a specified threshold. Since correlation detectors exploit the fine structure of the full waveform, they are exquisitely sensitive when compared to power (STA/LTA) detectors. The drawback of correlation detectors is that they require complete knowledge of the signal to be detected, which limits such methods to instances of seismicity in which a very similar signal has already been observed by every station used. Such instances include earthquake swarms, aftershock sequences, repeating industrial seismicity, and many other forms of controlled explosions. The reduction in the detection threshold is even greater when the techniques are applied to arrays since stacking can be performed on the individual channel correlation traces to achieve significant array gain. In previous years we have characterized the decrease in detection threshold afforded by correlation detection across an array or network when observations of a previous event provide an adequate template for signals from subsequent events located near the calibration event. Last year we examined two related issues: (1) the size of the source region calibration footprint afforded by a master event, and (2) the use of temporally incoherent detectors designed to detect the gross envelope structure of the signal to extend the footprint. In Case 1, results from the PETROBAR-1 marine refraction profile indicated that array correlation gain was usable at inter-source separations out to one or two wavelengths. In Case 2, we found that incoherent detectors developed from a magnitude 6 event near Svalbard were successful at detecting aftershocks where correlation detectors derived from individual aftershocks were not. Incoherent detectors might provide 'seed' events for correlation detectors that then could extend detection to lower magnitudes. This year we addressed a problem long known to limit the acceptance of correlation detectors in practice: the labor intensive development of templates. For example, existing design methods cannot keep pace with rapidly unfolding aftershock sequences. We successfully built and tested an object-oriented framework (as described in our 2005 proposal) for autonomous calibration of waveform correlation detectors for an array. The framework contains a dynamic list of detectors of several types operating on a continuous array data stream. The list has permanent detectors: beam forming power (STA/LTA) detectors which serve the purpose of detecting signals not yet characterized with a waveform template. The framework also contains an arbitrary number of subspace detectors which are launched automatically using the waveforms from validated power detections as templates. The implementation is very efficient such that the computational cost of adding subspace detectors was low. The framework contains a supervisor that oversees the validation of power detections, and periodically halts the processing to revise the portfolio of detectors. The process of revision consists of collecting the waveforms from all detections, performing cross-correlations pairwise among all waveforms, clustering the detections using correlations as a distance measure, then creating a new subspace detector from each cluster. The collection of new subspace detectors replaces the existing portfolio and processing of the data stream resumes. This elaborate scheme was implemented to prevent proliferation of closely-related subspace detectors. The method performed very well on several simple sequences: 2005 'drumbeat' events observed locally at Mt. St. Helens, and the 2003 Orinda, CA aftershock sequence. Our principal test entailed detection of the aftershocks of the San Simeon earthquake using the NVAR array; in this case, the system automatically detected and categorized approximately 2/3 of the events above magnitude 2.8.

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

2009-07-23

156

The Cosmic Muon Detector Array at Westmont College  

NASA Astrophysics Data System (ADS)

At Westmont College we have designed and constructed the Cosmic Muon Detector Array (CMDA), consisting of 8 1-m long position-sensitive scintillator detector bars arranged in two layers of 4 detectors each, one above the other. The purpose of the array has been to measure and monitor the cosmic muon flux over a large angular range in the sky - approximately ± 50^o (north-south) by ± 30^o (east-west), by correlating event positions between the two layers. The CMDA also monitors the long term north-south sky flux ratio, binned by sidereal hour, to look for possible flux correlations from cosmic sources including the galactic core. The detectors, electronics, and analysis software was modeled after the Modular Neutron Array (MoNA) located at the NSCL, Michigan State University, and simultaneous flux correlations for the CMDA and MoNA were monitored for approximately 1 week. After taking over a year's worth of data, the original array burned in a campus wildfire, which was then replaced by the second generation array (currently in operation). The CMDA serves both as a training ground for students preparing for participation in MoNA collaboration experiments as well as for Westmont student research experience.

Rogers, Warren

2012-03-01

157

Detectors based on silicon photomultiplier arrays for medical imaging applications  

SciTech Connect

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)

Llosa, G.; Barrio, J.; Cabello, J.; Lacasta, C.; Oliver, J. F. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Rafecas, M. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Departamento de Fisica Atomica, Molecular Y Nuclear, Universitat de Valencia, Valencia (Spain); Stankova, V.; Solaz, C. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Bisogni, M. G.; Del Guerra, A. [Universite di Pisa, INFN Pisa, Pisa (Italy)

2011-07-01

158

Coupling physics to understanding the performance of detector arrays  

NASA Astrophysics Data System (ADS)

Over the last few decades developments in microelectronics have led to the development of arrays of detectors that can be used to measure unprecedentedly small levels of signal. Such arrays have been used over to detect electromagnetic radiation ranging in energy from the X-ray through sub-millimeter wavelengths and also particles. Perhaps nowhere have the improvements been more astonishing than in devices available for the visible part of the spectrum (400 -- 1000 nm). The most successful detector array in this spectral region is the Charge Coupled Detector (CCD) whose inventors were recognized with the Nobel Prize in Physics in 2009. In this talk I will review some of the detectors and technologies that are used in low light level imaging. I will also describe a full year sequence of classes (i.e. a theory class, a CCD camera building class and a CCD camera performance measurement class) that students at the Rochester Institute of Technology can take to make them knowledgeable as to the physics underlying the operation and performance of such detector arrays. Finally I will discuss the associated laboratory classes that students must take to measure the performance of the camera they have built and what aspects of fundamental physics are integrated into their understanding. These classes have been taken by both calculus and non-calculus trained students. The classes appeal to students with both types of backgrounds as it couples an understanding of Physics to something that they have built and use.

Ninkov, Zoran

2012-02-01

159

SRAM As An Array Of Energetic-Ion Detectors  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

160

Uncooled Detectors Challenges for THz\\/sub-THz Arrays Imaging  

Microsoft Academic Search

Some problems and challenges for applications of uncooled or slightly cooled detectors (not deeper than to 77 K) for sub-THz\\u000a and THz (terahertz) arrays are briefly discussed. The possibilities to involve detectors based on plasmon resonance FETs (field\\u000a effect transistors) and those based on warm electron effect narrow-gap semiconductor bolometers are speculated, as they seem\\u000a to be promising for using in

Fiodor F. Sizov; Vladimir P. Reva; Alexandr G. Golenkov; Vyacheslav V. Zabudsky

161

Cosmic rays studied with a hybrid high school detector array  

E-print Network

The LORUN/NAHSA system is a pathfinder for hybrid cosmic ray research combined with education and outreach in the field of astro-particle physics. Particle detectors and radio antennae were mainly setup by students and placed on public buildings. After fully digital data acquisition, coincidence detections were selected. Three candidate events confirmed a working prototype, which can be multiplied to extend further particle detector arrays on high schools.

A. Nigl; C. Timmermans; P. Schellart; J. Kuijpers; H. Falcke; A. Horneffer; C. M. de Vos; Y. Koopman; H. J. Pepping; G. Schoonderbeek

2008-09-16

162

Separation of picrocrocin, cis-trans-crocins and safranal of saffron using high-performance liquid chromatography with photodiode-array detection.  

PubMed

High-performance liquid chromatography with photodiode-array detection was used to separate picrocrocin (bitter-tasting component, glucoside of safranal), cis/trans-crocins (carotenoids, glucosyl esters of crocetin) and safranal (flavour, monoterpene aldehyde) of saffron. All components of pure red Greek saffron were extracted from dried stigma with 50% methanol. These compounds were detected, separated collected and identified simultaneously using a Merck LiChroCART 125-4 Superspher 100 RP-18 (4 microns) column and as mobile phase a linear gradient from 20% to 100% acetonitrile in water in 20 min with a detection wavelength at 308 nm. PMID:8012549

Tarantilis, P A; Polissiou, M; Manfait, M

1994-03-25

163

LHD plasma emission measurements by means of absolute XUV photodiodes  

Microsoft Academic Search

The paper describes the measurements of the LHD plasma total radiation. The 16-channel pinhole type array was based on Absolute XUV photodiodes (AXUVD) (www.ird-inc.com). The detectors have an extended range of photon energies 20 eV \\\\x81E10 keV, for which sensitivity is high and approximately constant (0.22-0.27 A\\/W). AXUV diodes are also fast, miniature, easy to use and relatively inexpensive. The

Artem Kostrioukov; Byron Peterson; Shigeru Sudo; Masaki Osakabe; Tetuo Ozaki; Katsumi Ida

2001-01-01

164

Conceptual design of a hybrid Ge:Ga detector array  

NASA Technical Reports Server (NTRS)

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.

Parry, C. M.

1984-01-01

165

Si:Bi switched photoconducttor infrared detector array  

NASA Technical Reports Server (NTRS)

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.

Eakin, C. E.

1983-01-01

166

A Broadband Superconducting Detector Suitable for Use in Large Arrays  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

167

High resolution decoding of Multi-Anode Microchannel Array detectors  

NASA Technical Reports Server (NTRS)

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.

Kasle, David B.; Morgan, Jeffrey S.

1991-01-01

168

A readout for large arrays of microwave kinetic inductance detectors.  

PubMed

Microwave kinetic inductance detectors (MKIDs) are superconducting detectors capable of counting single photons and measuring their energy in the UV, optical, and near-IR. MKIDs feature intrinsic frequency domain multiplexing (FDM) at microwave frequencies, allowing the construction and readout of large arrays. Due to the microwave FDM, MKIDs do not require the complex cryogenic multiplexing electronics used for similar detectors, such as transition edge sensors, but instead transfer this complexity to room temperature electronics where they present a formidable signal processing challenge. In this paper, we describe the first successful effort to build a readout for a photon counting optical/near-IR astronomical instrument, the ARray Camera for Optical to Near-infrared Spectrophotometry. This readout is based on open source hardware developed by the Collaboration for Astronomy Signal Processing and Electronics Research. Designed principally for radio telescope backends, it is flexible enough to be used for a variety of signal processing applications. PMID:22559560

McHugh, Sean; Mazin, Benjamin A; Serfass, Bruno; Meeker, Seth; O'Brien, Kieran; Duan, Ran; Raffanti, Rick; Werthimer, Dan

2012-04-01

169

Order-sorting filter transmittance measured with an array detector  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

170

New air fluorescence detectors employed in the Telescope Array experiment  

NASA Astrophysics Data System (ADS)

Since 2007, the Telescope Array (TA) experiment, based in Utah, USA, has been observing ultra high energy cosmic rays to understand their origins. The experiment includes a surface detector (SD) array and three fluorescence detector (FD) stations. The FD stations, installed surrounding the SD array, measure the air fluorescence light emitted from extensive air showers (EASs) for precise determination of their energies and species. The detectors employed at one of the three FD stations were relocated from the High Resolution Fly's Eye (HiRes) experiment. At the other two stations, newly designed detectors were constructed for the TA experiment. An FD consists of a primary mirror and a camera equipped with photomultiplier tube pixels. To obtain the EAS parameters with high accuracy, understanding the FD optical characteristics is important. In this paper, we report the characteristics and installation of the new FDs and the performances of the FD components. The results of the monitored mirror reflectance during the observation time are also described in this report.

Tokuno, H.; Tameda, Y.; Takeda, M.; Kadota, K.; Ikeda, D.; Chikawa, M.; Fujii, T.; Fukushima, M.; Honda, K.; Inoue, N.; Kakimoto, F.; Kawana, S.; Kido, E.; Matthews, J. N.; Nonaka, T.; Ogio, S.; Okuda, S.; Ozawa, S.; Sagawa, H.; Sakurai, N.; Shibata, T.; Taketa, A.; Thomas, S. B.; Tomida, T.; Tsunesada, Y.; Udo, S.; 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.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fukuda, T.; Gorbunov, D.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Iguchi, T.; Ikuta, K.; Ishii, T.; Ishimori, R.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lim, S. I.; Machida, S.; Martens, K.; Martineau, J.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Myers, I.; Minamino, M.; Miyata, K.; Miyauchi, H.; Murano, Y.; Nakamura, T.; Nam, S. W.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Oshima, A.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; 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.; Suzuki, S.; Takahashi, Y.; Takita, M.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Troitsky, S.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Wood, M.; Yamakawa, Y.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2012-06-01

171

The NSLS 100 element solid state array detector  

SciTech Connect

X-ray absorption studies of dilute samples require fluorescence detection techniques. Since signal-to-noise ratios are governed by the ratio of fluorescent to scattered photons counted by a detector, solid state detectors which can discriminate between fluorescence and scattered photons have become the instruments of choice for trace element measurements. Commercially available 13 element Ge array detectors permitting total count rates < 500,000 counts per second are now in routine use. Since x-ray absorption beamlines at high brightness synchrotron sources can already illuminate most dilute samples with enough flux to saturate the current generation of solid state detectors, the development of next-generation instruments with significantly higher total count rates is essential. We present the design and current status of the 100 element Si array detector being developed in a collaboration between the NSLS and the Instrumentation Division at Brookhaven National Laboratory. The detecting array consists of a 10*10 matrix of 4mm * 4mm elements laid out on a single piece of ultra-high purity silicon mounted at the front end of a liquid nitrogen dewar assembly. A matrix of charge sensitive integrating preamplifiers feed signals to an array of shaping amplifiers, single channel analyzers, and scalers. An electronic switch, delay amplifier, linear gate, digital scope, peak sensing A to D converter, and histogramming memory module provide for complete diagnostics and channel calibration. The entire instrument is controlled by a LabView 2 application on a MacII ci; the software also provides full control over beamline hardware and performs the data collection.

Furenlid, L.R.; Kraner, H.W.; Rogers, L.C.; Stephani, D.; Beuttenmuller, R.H.; Beren, J. [Brookhaven National Lab., Upton, NY (United States); Cramer, S.P. [California Univ., Davis, CA (United States). Dept. of Applied Science

1991-12-31

172

The NSLS 100 element solid state array detector  

SciTech Connect

X-ray absorption studies of dilute samples require fluorescence detection techniques. Since signal-to-noise ratios are governed by the ratio of fluorescent to scattered photons counted by a detector, solid state detectors which can discriminate between fluorescence and scattered photons have become the instruments of choice for trace element measurements. Commercially available 13 element Ge array detectors permitting total count rates < 500,000 counts per second are now in routine use. Since x-ray absorption beamlines at high brightness synchrotron sources can already illuminate most dilute samples with enough flux to saturate the current generation of solid state detectors, the development of next-generation instruments with significantly higher total count rates is essential. We present the design and current status of the 100 element Si array detector being developed in a collaboration between the NSLS and the Instrumentation Division at Brookhaven National Laboratory. The detecting array consists of a 10*10 matrix of 4mm * 4mm elements laid out on a single piece of ultra-high purity silicon mounted at the front end of a liquid nitrogen dewar assembly. A matrix of charge sensitive integrating preamplifiers feed signals to an array of shaping amplifiers, single channel analyzers, and scalers. An electronic switch, delay amplifier, linear gate, digital scope, peak sensing A to D converter, and histogramming memory module provide for complete diagnostics and channel calibration. The entire instrument is controlled by a LabView 2 application on a MacII ci; the software also provides full control over beamline hardware and performs the data collection.

Furenlid, L.R.; Kraner, H.W.; Rogers, L.C.; Stephani, D.; Beuttenmuller, R.H.; Beren, J. (Brookhaven National Lab., Upton, NY (United States)); Cramer, S.P. (California Univ., Davis, CA (United States). Dept. of Applied Science)

1991-01-01

173

Short wave infrared InGaAs focal plane arrays detector: the performance optimization of photosensitive element  

NASA Astrophysics Data System (ADS)

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 (?=1.55?m) was 6×1012 cmHz1/2W-1 and dynamics range reached 68 dB at room temperature. Making use of the fabricated 320×256 InGaAs FPA, the concerning objects can be imaged in the low light level or nightglow background.

Gao, Xin-jiang; Tang, Zun-lie; Zhang, Xiu-chuan; Chen, Yang; Jiang, Li-qun; Cheng, Hong-bing

2009-07-01

174

Plans for CHICOS a detector array in California High Schools  

NASA Astrophysics Data System (ADS)

The California HIgh school Cosmic ray ObServatory, CHICOS, is a collabora-tive project involving Caltech, Cal State Northridge, UC Irvine, and local high school physics teachers to site a large array of particle detectors at high schools in the Los Angeles area. The Los Angeles basin is quite unique in that there is a very large area (> 5000 km2 ) of uniformly dense population with available high school infrastructure. We have obtained 164 scintillation detectors from the decommissioned CYGNUS experiment in New Mexico, and are presently working to instrument these detectors in an array with area of more than 400 km2 . Each site will have a detection system with a computer to acquire data, and will operate in an autonomous mode using GPS time-stamping of events. The data from each site will be transmitted via internet to a central computer at Caltech where the data will be logged, processed, and accessible to the high schools. The availability of existing infrastructure in the Los Angeles school system with internet connections, power, and shelter provides an excellent op-portunity to develop such a large array. In the future we would like to expand the scope of this project to cover a larger fraction of the Los Angeles area and include a much larger percentage of the high schools, hopefully increasing the area to over 1000 km2 .

McKeown, R. D.; Carr, R.; Gao, J.; Guerrera, T.; Horton-Smith, S.; Ito, T.; Seki, R.; Li, S.-P.; Shoup, A.; Yodh, G.

175

Imaging MAMA detector systems. [Multi-Anode Microchannel Array  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

176

Analysis of 12 different pentacyclic triterpenic acids from frankincense in human plasma by high-performance liquid chromatography and photodiode array detection.  

PubMed

For the determination of pentacyclic triterpenes of the boswellic acid family in human plasma a novel sensitive method was developed combining serial extraction on diatomaceous earth and graphitized carbon black followed by reversed phase high-performance liquid chromatography (HPLC) and photodiode array detection. The overall average extraction yield of 12 different pentacyclic triterpenic acids was approximately 66%. The calibration graphs were linear with coefficients of correlation for all compounds greater than 0.999. The overall within-day and between-day coefficients of variation (CV) for the 12 pentacyclic triterpenic acids were 5.6 and 6.8%, respectively. This HPLC procedure delivers the analytical sensitivity, precision and accuracy required for clinical pharmacokinetic and therapeutic studies. PMID:14522040

Büchele, Berthold; Simmet, Thomas

2003-10-01

177

Design of a silicon avalanche photodiode pixel with integrated laser diode using back-illuminated crystallographically etched silicon-on-sapphire with monolithically integrated microlens for dual-mode passive and active imaging arrays  

NASA Astrophysics Data System (ADS)

There is a growing need in scientific research applications for dual-mode, passive and active 2D and 3D LADAR imaging methods. To fill this need, an advanced back-illuminated silicon avalanche photodiode (APD) design is presented using a novel silicon-on-sapphire substrate incorporating a crystalline aluminum nitride (AlN) antireflective layer between the silicon and R-plane sapphire. This allows integration of a high quantum efficiency silicon APD with a gallium nitride (GaN) laser diode in each pixel. The pixel design enables single photon sensitive, solid-state focal plane arrays (FPAs) with wide dynamic range, supporting passive and active imaging capability in a single FPA. When (100) silicon is properly etched with TMAH solution, square based pyramidal frustum or mesa arrays result with the four mesa sidewalls of the APD formed by (111) silicon planes that intersect the (100) planes at a crystallographic angle, ? c = 54.7°. The APD device is fabricated in the mesa using conventional silicon processing technology. The GaN laser diode is fabricated by epitaxial growth inside of an inverted, etched cavity in the silicon mesa. Microlenses are fabricated in the thinned, and AR-coated sapphire substrate. The APDs share a common, front-side anode contact, and laser diodes share a common cathode. A low resistance (Al) or (Cu) metal anode grid fills the space between pixels and also inhibits optical crosstalk. SOS-APD arrays are flip-chip bump-bonded to CMOS readout ICs to produce hybrid FPAs. The square 27 ?m emitter-detector pixel achieves SNR > 1 in active detection mode for Lambert surfaces at 1,000 meters.

Stern, Alvin G.

2010-08-01

178

Development of photodetection system based on multipixel avalanche Geiger photodiodes with WLS for LXe low-background detectors  

Microsoft Academic Search

A multipixel avalanche Geiger photodiode with a p-terphenyl wavelength shifter in front of it has been tested in the liquid xenon to detect the 175-nm scintillation light. The global detection efficiency of the VUV photons of ~10% is obtained. A photodetection system with sensitivity to sub-keV ionization and few-mm coordinate accuracy is proposed for LXe low-background experiments.

D. Yu. Akimov; A. V. Akindinov; I. S. Alexandrov; A. A. Burenkov; M. V. Danilov; A. G. Kovalenko; V. N. Stekhanov

2010-01-01

179

Development of photodetection system based on multipixel avalanche Geiger photodiodes with WLS for LXe low-background detectors  

Microsoft Academic Search

A multi pixel avalanche Geiger photodiode with a p-terphenyl wavelength shifter in front of it has been tested in the liquid xenon to detect the 175-nm scintillation light. The global detection efficiency of the VUV photons of -10% is obtained. A photodetection system with sensitivity to sub-keY ionization and few-mm coordinate accuracy is proposed for LXe low-background experiments. photomultipliers l

D. Yu. Akimov; M. V. Danilov; Y. N. Stekhanov

180

Development of photodetection system based on multipixel avalanche Geiger photodiodes with WLS for LXe low-background detectors  

NASA Astrophysics Data System (ADS)

A multipixel avalanche Geiger photodiode with a p-terphenyl wavelength shifter in front of it has been tested in the liquid xenon to detect the 175-nm scintillation light. The global detection efficiency of the VUV photons of ~10% is obtained. A photodetection system with sensitivity to sub-keV ionization and few-mm coordinate accuracy is proposed for LXe low-background experiments.

Akimov, D. Yu.; Akindinov, A. V.; Alexandrov, I. S.; Burenkov, A. A.; Danilov, M. V.; Kovalenko, A. G.; Stekhanov, V. N.

2010-04-01

181

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

NASA Astrophysics Data System (ADS)

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 8-15?m spectral range. The performance of a (112x112) pixel photodiode array with a 40?m 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 ~14.4?m 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%.

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

182

Fast, High-Precision Readout Circuit for Detector Arrays  

NASA Technical Reports Server (NTRS)

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.

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

183

The High Resolution Array (HiRA) Detector  

NASA Astrophysics Data System (ADS)

The High Resolution Array is set of charged particle detectors being built at the NSCL at Michigan State University, IUCF at Indiana University, and the Washington University chemistry department, for experiments at the NSCL as well as other facilities. The array consists of 20 charged particle telescopes. Each telescope contains 2 silicon strip detectors backed by 4 CsI(Tl) crystals. The front silicon is 65 microns thick and is segmented into 32 strips. The second silicon is 1.5 mm thick and has 32 strips on the front and backsides. The 4 CsI(Tl) crystals are 4 cm thick and cover 1/4 of the surface of the silicon. Because of the large number of silicon strips that need to be readout the Washington University group developed a chip, which consist of pre-amplifiers, shapers, discriminators, and TAC's. The different elements of the detector will be discussed in detail and results of ongoing tests of the complete HiRA telescopes and their ASIC electronics will be described. Work supported by the NSF, grant NSF-PHY-01-10253

Wallace, Mark S.; Famiano, Michael; van Goethem, Marc-Jan; Nett, Brian; Rogers, Andrew; Delauney, Franck; Lynch, W. G.; Tsang, M. B.; Mocko, Michal; Sobotka, Lee; Elson, Jon; Engel, George; de Souza, Romauldo; Hudan, Sylvie; Viola, Vic; Moroni, Arialdo

2004-10-01

184

Curved-channel microchannel array plates. [photoelectric detectors  

NASA Technical Reports Server (NTRS)

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.

Timothy, J. G.

1981-01-01

185

Undersampling Correction for Array Detector-Based Satellite Spectrometers  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

186

An MLC calibration method using a detector array  

SciTech Connect

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.

Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray [Department of Nuclear and Radiological Engineering, University of Florida, 202 Nuclear Science Building, Gainesville, Florida 32611-8300 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States) and Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States); Department of Radiation Oncology, Tulane University, 1415 Tulane Ave, HC65, New Orleans, Louisiana 70112 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)

2009-10-15

187

Two detector arrays for fast neutrons at LANSCE  

NASA Astrophysics Data System (ADS)

The neutron spectrum from neutron-induced fission needs to be known in designing new fast reactors, predicting criticality for safety analyses, and developing techniques for global security application. The experimental data base of fission neutron spectra is very incomplete and most present evaluated libraries are based on the approach of the Los Alamos Model. To validate these models and to provide improved data for applications, a program is underway to measure the fission neutron spectrum for a wide range of incident neutron energies using the spallation source of fast neutrons at the Weapons Neutron Research (WNR) facility at the Los Alamos Neutron Science Center (LANSCE). In a double time-of-flight experiment, fission neutrons are detected by arrays of neutron detectors to increase the solid angle and also to investigate possible angular dependence of the fission neutrons. The challenge is to measure the spectrum from low energies, down to 100 keV or so, to energies over 10 MeV, where the evaporation-like spectrum decreases by 3 orders of magnitude from its peak around 1 MeV. For these measurements, we are developing two arrays of neutron detectors, one based on liquid organic scintillators and the other on 6Li-glass detectors. The range of fission neutrons detected by organic liquid scintillators extends from about 600 keV to well over 10 MeV, with the lower limit being defined by the limit of pulse-shape discrimination. The 6Li-glass detectors have a range from very low energies to about 1 MeV, where their efficiency then becomes small. Various considerations and tests are in progress to understand important contributing factors in designing these two arrays and they include selection and characterization of photomultiplier tubes (PM), the performance of relatively thin (1.8 cm) 6Li-glass scintillators on 12.5 cm diameter PM tubes, use of 17.5 cm diameter liquid scintillators with 12.5 cm PM tubes, measurements of detector efficiencies with tagged neutrons from the WNR/LANSCE neutron beam, and efficiency calibration with 252Cf spontaneous fission neutrons. Design considerations and test results are presented.

Haight, R. C.; Lee, H. Y.; Taddeucci, T. N.; O'Donnell, J. M.; Perdue, B. A.; Fotiades, N.; Devlin, M.; Ullmann, J. L.; Laptev, A.; Bredeweg, T.; Jandel, M.; Nelson, R. O.; Wender, S. A.; White, M. C.; Wu, C. Y.; Kwan, E.; Chyzh, A.; Henderson, R.; Gostic, J.

2012-03-01

188

Multispectral breast imaging using a ten-wavelength, 64x64 source/detector channels silicon photodiode-based diffuse optical tomography system  

SciTech Connect

We describe a compact diffuse optical tomography system specifically designed for breast imaging. The system consists of 64 silicon photodiode detectors, 64 excitation points, and 10 diode lasers in the near-infrared region, allowing multispectral, three-dimensional optical imaging of breast tissue. We also detail the system performance and optimization through a calibration procedure. The system is evaluated using tissue-like phantom experiments and an in vivo clinic experiment. Quantitative two-dimensional (2D) and three-dimensional (3D) images of absorption and reduced scattering coefficients are obtained from these experiments. The ten-wavelength spectra of the extracted reduced scattering coefficient enable quantitative morphological images to be reconstructed with this system. From the in vivo clinic experiment, functional images including deoxyhemoglobin, oxyhemoglobin, and water concentration are recovered and tumors are detected with correct size and position compared with the mammography.

Li Changqing; Zhao Hongzhi; Anderson, Bonnie; Jiang Huabei [Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States); Department of Radiology, Oconee Memorial Hospital, Seneca, South Carolina 29672 (United States); Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States)

2006-03-15

189

Cerenkov radiators for photodiodes  

NASA Astrophysics Data System (ADS)

Several materials were examined for use as Cerenkov converters in front of photodiodes in an effort to find a gamma detector system that has more sensitivity than a Compton detector but makes little sacrifice in bandwidth. Suprasil (fused silica) and UVT Lucite (acrylic) were 10 to 100 times more sensitive than a Compton detector and provided almost the same bandwidth. Barium fluoride provided almost 1000 times the sensitivity, but with a factor of 3 or 4 reduction in bandwidth. Relative sensitivities are strongly dependent on beam composition; the Cerenkov package is less sensitive to a pure gamma ray beam than to a gamma electron shower beam. Hence, beam composition must be considered in any application of these detectors.

Toevs, J. W.; Young, C. S.; Zagarino, P. A.; Seno, R. D.

190

Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry  

NASA Astrophysics Data System (ADS)

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 polarization measurements.

Bock, James

2014-01-01

191

Capillary Array Waveguide Amplified Fluorescence Detector for mHealth.  

PubMed

Mobile Health (mHealth) analytical technologies are potentially useful for carrying out modern medical diagnostics in resource-poor settings. Effective mHealth devices for underserved populations need to be simple, low cost, and portable. Although cell phone cameras have been used for biodetection, their sensitivity is a limiting factor because currently it is too low to be effective for many mHealth applications, which depend on detection of weak fluorescent signals. To improve the sensitivity of portable phones, a capillary tube array was developed to amplify fluorescence signals using their waveguide properties. An array configured with 36 capillary tubes was demonstrated to have a ~100X increase in sensitivity, lowering the limit of detection (LOD) of mobile phones from 1000 nM to 10 nM for fluorescein. To confirm that the amplification was due to waveguide behavior, we coated the external surfaces of the capillaries with silver. The silver coating interfered with the waveguide behavior and diminished the fluorescence signal, thereby proving that the waveguide behavior was the main mechanism for enhancing optical sensitivity. The optical configuration described here is novel in several ways. First, the use of capillaries waveguide properties to improve detection of weak florescence signal is new. Second we describe here a three dimensional illumination system, while conventional angular laser waveguide illumination is spot (or line), which is functionally one-dimensional illumination, can illuminate only a single capillary or a single column (when a line generator is used) of capillaries and thus inherently limits the multiplexing capability of detection. The planar illumination demonstrated in this work enables illumination of a two dimensional capillary array (e.g. x columns and y rows of capillaries). In addition, the waveguide light propagation via the capillary wall provides a third dimension for illumination along the axis of the capillaries. Such an 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

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

2013-09-01

192

Antenna coupled detectors for 2D staring focal plane arrays  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

193

Design of a CMOS Potentiostat Circuit for Electrochemical Detector Arrays  

PubMed Central

High-throughput electrode arrays are required for advancing devices for testing the effect of drugs on cellular function. In this paper, we present design criteria for a potentiostat circuit that is capable of measuring transient amperometric oxidation currents at the surface of an electrode with submillisecond time resolution and picoampere current resolution. The potentiostat is a regulated cascode stage in which a high-gain amplifier maintains the electrode voltage through a negative feedback loop. The potentiostat uses a new shared amplifier structure in which all of the amplifiers in a given row of detectors share a common half circuit permitting us to use fewer transistors per detector. We also present measurements from a test chip that was fabricated in a 0.5-?m, 5-V CMOS process through MOSIS. Each detector occupied a layout area of 35?m × 15?m and contained eight transistors and a 50-fF integrating capacitor. The rms current noise at 2kHz bandwidth is ? 110fA. The maximum charge storage capacity at 2kHz is 1.26 × 106 electrons. PMID:20514150

Ayers, Sunitha; Gillis, Kevin D.; Lindau, Manfred; Minch, Bradley A.

2010-01-01

194

Fluorometric flow-immunoassay for alkylphenol polyethoxylates on a microchip containing a fluorescence detector comprised of an organic light emitting diode and an organic photodiode.  

PubMed

A compact fluorescence detector was constructed on a microchip from an organic light emitting diode (OLED) as the light source and an organic photodiode (OPD) as the photo-detector and was used in an immunoassay for alkylphenol polyethoxylates (APE). The OLED based on a terbium complex emitted a sharp light at the main wavelength of 546nm with a full width at half maximum of 9nm. The incident photo-to-current conversion efficiency (IPCE) of the OPD fabricated with Fullerene 70 (C70) and tris[4-(5-phenylthiopen-2-yl)phenyl]-amine (TPTPA) was approximately 44% for light at a wavelength of 586nm. The performance of the fluorescence detector was evaluated for the determination of resorufin (?em=586nm) and the photocurrent of the OPD due to the fluorescence of resorufin was proportional to the concentration of resorufin in the range from 0 to 18µM with a detection limit (S/N=3) of 0.6µM. The fluorescence detector was successfully utilized in a competitive enzyme-linked immunosorbent assay for APE, where an anti-APE antibody was immobilized on the surface of the channel of the Polydimethylsiloxane (PDMS) microchip or on the surface of magnetic microbeads. After an immunoreaction with a sample solution of APE containing a horse radish peroxidase (HRP)-labeled APE, the fluorescence of resorufin generated just after introduction of a mixed solution of Amplex Red and H2O2 was measured using the fluorescence detector. The calibration curve for the photocurrent signals of the OPD due to the fluorescence of resorufin against the logarithmic concentration of APE was sigmoidal in shape. The detection limits defined as IC80 were ca. 1ppb and ca. 2ppb, respectively, for the methods using the anti-APE antibody immobilized on the surface of the microchannel and in the case where the antibody was immobilized on the surface of magnetic microbeads. PMID:25618638

Liu, Rong; Ishimatsu, Ryoichi; Yahiro, Masayuki; Adachi, Chihaya; Nakano, Koji; Imato, Toshihiko

2015-03-01

195

16 x 25 Ge:Ga Detector Arrays for FIFI LS  

E-print Network

We are developing two-dimensional 16 x 25 pixel detector arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-infrared astronomy from SOFIA. The arrays, based on earlier 5 x 5 detector arrays used on the KAO, will be for our new instrument, the Far Infrared Field Imaging Line Spectrometer (FIFI LS). The unstressed Ge:Ga detector array will cover the wavelength range from 40 to 120 microns, and the stressed Ge:Ga detector array from 120 to 210 microns. The detector arrays will be operated with multiplexed integrating amplifiers with cryogenic readout electronics located close to the detector arrays. The design of the stressed detector array and results of current measurements on several prototype 16 pixel linear arrays are reported. They demonstrate the feasibility of the current concept. ***This paper does not include Figures due to astro-ph size limitations. Please download entire file at http://fifi-ls.mpe-garching.mpg.de/spie.det.ps.gz ***

D. Rosenthal; J. W. Beeman; N. Geis; L. Looney; A. Poglitsch; W. K. Park; W. Raab; A. Urban

2000-03-23

196

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

NASA Technical Reports Server (NTRS)

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.

Ando, K. J.

1978-01-01

197

LAMBDA — Large Area Medipix3-Based Detector Array  

NASA Astrophysics Data System (ADS)

Medipix3 is a photon-counting readout chip for X-ray detection. It has a small pixel size (55 ?m) and a high frame rate with zero dead time, which makes it attractive for experiments at synchrotrons. Using Medipix3, DESY are developing the LAMBDA (Large Area Medipix3-Based Detector Array) system. A single LAMBDA module carries either a single large silicon sensor of 1536 by 512 pixels, or two smaller high-Z sensors. The sensor is bonded to 12 Medipix3 chips, and mounted on a ceramic carrier board. The readout system for the module then provides a fast FPGA, a large RAM and four 10 Gigabit Ethernet links to allow operation at high frame rates. Multiple modules may then be tiled together a larger area. Currently, the first large silicon modules have been constructed and tested at low speed, and the firmware for fast readout is being developed.

Pennicard, D.; Lange, S.; Smoljanin, S.; Hirsemann, H.; Graafsma, H.

2012-11-01

198

InGaAs detector arrays hermetic encapsulation technology  

NASA Astrophysics Data System (ADS)

In this paper, 256×1 and 512×1 element linear InGaAs detector arrays are hermetic packaged. Some processes were studied, including the structure design, thermoelectric cooler (TEC) heat load performance test, TEC vacuum baking, the window sealing, the seam welding of the cover lid and shell, and so on. The results show that the cooling temperature difference of TEC can reach over 55 K at room temperature, and it decreases by about 0.51 K with each additional 50 mW heat load. TEC works well after 500 hours of baking at 120 °C. The leakage rate tests show the assembly is better than 10-5 Pa.cm3/s.

Xu, Qinfei; Liu, Dafu

2010-10-01

199

The fully integrated Schottky array - A new generation of metal silicide infrared detectors  

Microsoft Academic Search

A proposal for a metal-silicide full Schottky IR detector array is presented. IR detection and charge transfer are conducted with metal silicide gates which lie directly on silicon, and a detector array designed as a frame transfer device. A half-Schottky CCD was developed to probe the concept, with one phase gate built as a Schottky silicide gate. A more advanced

U. Theden; M. A. Green; J. W. V. Storey; J. M. Kurianski

1990-01-01

200

Energy spectrum measured by the telescope array surface detector  

NASA Astrophysics Data System (ADS)

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.

Ivanov, Dmitri

2012-05-01

201

HgCdTe e-APD detector arrays with single photon sensitivity for space lidar applications  

NASA Astrophysics Data System (ADS)

A multi-element HgCdTe electron initiated avalanche photodiode (e-APD) array has been developed for space lidar. The detector array was fabricated with 4.3?m cutoff HgCdTe with a spectral response from 0.4 to 4.3 ?m. We have demonstrated a 4x4 e-APD array with 80 ?m 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 ?m 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.

Sun, Xiaoli; Abshire, James B.; Beck, Jeffrey D.

2014-05-01

202

Method of fabricating multiwavelength infrared focal plane array detector  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

203

Ultrasound-assisted solid-phase extraction coupled with photodiode-array and fluorescence detection for chemotaxonomy of isoflavone phytoestrogens in Trifolium L. (Clover) species.  

PubMed

Detailed chemotaxonomic studies were undertaken to establish the qualitative profile and real amounts of the pharmacologically active isoflavone aglycones genistein, daidzein, formononetin, and biochanin A in aerial parts of thirteen Trifolium L. (clover) species, native to Poland. A newly elaborated micropreparative technique--SPE--on BakerBond octadecyl, cyclohexyl, and phenyl cartridges was used in combination with ultrasound-assisted extraction for isolation of isoflavone aglycones from hydrolyzed samples. The effectiveness of all three SPE sorbents in the purification of plant extracts was compared and very high recoveries (>96%) were documented for four isoflavones. Classical photodiode-array and very sensitive fluorescence detection, coupled with reversed-phase high-performance liquid chromatography (RP-HPLC), were employed to obtain the most reliable qualitative and quantitative results. Chemotaxonomic differences combined with flower color variability were demonstrated within thirteen clover species. Concentration levels of particular isoflavones in ten Trifolium species possessing flowers with white, pink, or purple-red corolla ranged from approximately 3 to approximately 3300 microg/g dry weight, while in three yellow flowering clovers (T. aureum, T. dubium, and T. campestre) isoflavone compounds have not been detected at all. RSD values, determined for intra- and inter-day precision of the quantitative results, were not higher than 6.2% and 7.1%, respectively. PMID:19226567

Zgórka, Grazyna

2009-04-01

204

Quantification of tetramethyl-terephthalic acid in rat liver, spleen and urine matrices by liquid-liquid phase extraction and HPLC-photodiode array detection.  

PubMed

Tetramethyl-terephthalate (TMT) is the constitutive linker of the flexible porous iron(III) carboxylate Metal Organic Framework (MOF) MIL-88B_4CH? based drug nanocarrier (MIL stands for Material from Institut Lavoisier). A method for the determination of the concentration of tetramethyl-terephthalic acid has been developed in different biological rat matrices (liver, spleen and urine) using a liquid-liquid phase extraction and high-performance liquid chromatography (HPLC) coupled to photodiode array detection with 4-aminosalicylic acid as internal standard. The extraction conditions of TMT have been varied from urine to tissue depending on the complexity of the biological matrices. The chromatographic separation was performed with a gradient elution. In all matrices, the limits of detection and quantification of TMT was 0.01 and 0.05 ?g ml?¹, respectively. The recovery of the TMT reached 86, 89 and 97% for urine, spleen and liver tissues, respectively. The linearity of the calibration curves in urine and tissues was satisfactory in all cases as evidenced by correlation coefficients >0.990. The within-day and between-day precisions were <15% (n=6) and the accuracy ranged in all cases between 86 and 103%. This method has finally allowed the quantification of TMT in rat urine and in tissue samples of rats administered intravenously with iron(III) tetramethyltherepthalate MIL-88B_4CH? nanoparticles. PMID:22608098

Baati, Tarek; Horcajada, Patricia; David, Olivier; Gref, Ruxandra; Couvreur, Patrick; Serre, Christian

2012-01-01

205

Determination of the polyphenolic content of a Capsicum annuum L. extract by liquid chromatography coupled to photodiode array and mass spectrometry detection and evaluation of its biological activity.  

PubMed

The present study was aimed to investigate the polyphenolic profile of a pepper (Capsicum annuum L.) extract from Algeria and evaluate its biological activity. The total polyphenol content of the extract was determined as 1.373 mg of gallic acid equivalents (±0.0046), whereas the flavonoids were determined as 0.098 mg of quercetin (±0.0015). The determination of the complete polyphenolic profile of the extract was achieved by liquid chromatography with an RP-amide column in combination with photodiode array and mass spectrometry detection through an electrospray ionization interface. A total of 18 compounds were identified, of which five were reported for the first time in the sample tested. Quercetin rhamnoside was the most abundant compound (82.6 ?g/g of fresh pepper) followed by quercetin glucoside (19.86 ?g/g). The antioxidant activity and antimicrobial effects were also determined. For the antimicrobial tests assessed against Gram-positive and Gram-negative bacteria, kaempferol showed the strongest inhibitory effect followed by quercetin and caffeic acids. In the study of the cytotoxicity of the extract, the cancer cells (U937) were more affected than the normal cells (peripheral blood mononucleated cells), with more than 62% inhibition at the highest concentration. PMID:25378270

Mokhtar, Meriem; Soukup, Jan; Donato, Paola; Cacciola, Francesco; Dugo, Paola; Riazi, Ali; Jandera, Pavel; Mondello, Luigi

2015-01-01

206

Characterization of a CsI(Tl) array coupled to avalanche photodiodes for the Barrel of the CALIFA calorimeter at the NEPTUN tagged gamma beam facility  

NASA Astrophysics Data System (ADS)

Among the variety of crystal calorimeters recently designed for several physics facilities, CALIFA (CALorimeter for In-Flight emitted gAmmas and light-charged particles) has especially demanding requirements since it must perform within a very complicated energy domain (gamma-ray energies from 0.1 to 20 MeV and up to 300 MeV protons). As part of the R&D program for the Barrel section of CALIFA, a reduced geometry prototype was constructed. This prototype consisted of a 3 × 5 array of CsI(Tl) crystals of varying dimensions, coupled to large area avalanche photodiodes. Here reported are the details regarding the construction of the prototype and the experimental results obtained at the NEPTUN tagged gamma beam facility, reconstructing gamma energies up to 10 MeV. Dedicated Monte Carlo simulations of the setup were also performed, enabling a deeper understanding of the experimental data. The experimental results demonstrate the effectiveness of the reconstruction method and helped to establish the most suitable crystal geometry to be employed within the forthcoming calorimeter.

Gascón, M.; Schnorrenberger, L.; Pietras, B.; Álvarez-Pol, H.; Cortina-Gil, D.; Díaz Fernández, P.; Duran, I.; Glorius, J.; González, D.; Perez-Loureiro, D.; Pietralla, N.; Savran, D.; Sonnabend, K.

2013-10-01

207

Determination of plant hormones in fertilizers by high-performance liquid chromatography with photodiode array detection: method development and single-laboratory validation.  

PubMed

A simple and reliable high-performance liquid chromatographic method that uses photodiode array detection was developed for the simultaneous determination of 12 native and synthetic plant hormones, i.e., plant growth regulators (PGRs), in fertilizers, such as 1-naphthol, 2,4-dichlorophenoxyacetic acid, 4-(2,4-dichlorophenoxy)butyric acid, 4-chlorophenoxyacetic acid, indole-3-acetic acid, 4-(3-indolyl)butyric acid, dichlorprop, (4-chloro-2-methylphenoxy)acetic acid, alpha-naphthaleneacetic acid, 1-naphthaleneacetamide, beta-naphthoxyacetic acid, and thidiazuron. The method was experimentally validated for routine regulatory application, and the following analytical parameters were assessed for all PGRs studied: linearity; specificity; precision (relative standard deviation) and accuracy, both measured at 3 concentration levels (0.1, 0.05, and 0.01%, w/w); ruggedness; limit of detection; and limit of quantification. Results were satisfactory for all method validation parameters tested and for all PGRs studied, demonstrating the suitability of the method for the determination of PGRs in fertilizers. The uncertainty of measurement was also estimated at 3 concentration levels for all PGRs by using the approach of the International Organization for Standardization, described in its Guide to the Expression of Uncertainty in Measurement. The method was applied to 20 samples of liquid fertilizer with declared biostimulant properties. PMID:19202783

Gambino, Grazia Laura; Pagano, Pietro; Scordino, Monica; Sabatino, Leonardo; Scollo, Emanuele; Traulo, Pasqualino; Gagliano, Giacomo

2008-01-01

208

Determination of nitrofurans in animal feeds by liquid chromatography-UV photodiode array detection and liquid chromatography-ionspray tandem mass spectrometry.  

PubMed

Within the EU, the use of nitrofurans is prohibited in food production animals. For this reason detection of these compounds in feedingstuffs, at whatever limit, constitutes an offence under EU legislation. This detection generally involves the use of analytical methods with limits of quantification lowers than 1 mg kg(-1). These procedures are unsuitable for the detection and confirmation of trace amounts of nitrofurans in feedingstuffs due to contamination. It is well known that very low concentrations of these compounds can be the source of residues of nitrofuran metabolites in meat and other edible products obtained from animals consuming the contaminated feed. The present multi-compound method was capable of measuring very low concentrations of nitrofurantoin (NFT), nitrofurazone (NFZ), furazolidone (FZD) and furaltadone (FTD) in animal feed using nifuroxazide (NXZ) as internal standard. Following ethyl acetate extraction at mild alkaline conditions and purification on NH2 column, the nitrofurans are determined using liquid chromatography with photodiode-array detection (LC-DAD). It was observed a CCalpha ranged from 50 to 100 microg kg(-1). The liquid chromatography-tandem mass spectrometric (LC-MS/MS) procedure was used to confirm the identity of the suspected presence of any of the nitrofuran compounds. PMID:17386735

Barbosa, Jorge; Moura, Sara; Barbosa, Rita; Ramos, Fernando; da Silveira, Maria Irene Noronha

2007-03-14

209

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

NASA Astrophysics Data System (ADS)

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.

Wikner, David; Grossman, Erich

2009-05-01

210

Silicon-on-insulator shortwave infrared wavelength meter with integrated photodiodes for on-chip laser monitoring.  

PubMed

This paper demonstrates a very compact wavelength meter for on-chip laser monitoring in the shortwave infrared wavelength range based on an optimized arrayed waveguide grating (AWG) filter with an integrated photodiode array. The AWG response is designed to obtain large nearest neighbor crosstalk (i.e. large overlap) between output channels, which allows accurately measuring the wavelength of a laser under test using the centroid detection technique. The passive AWG is fabricated on a 220 nm silicon-on-insulator (SOI) platform and is combined with GaInAsSb-based photodiodes. The photodiodes are heterogeneously integrated on the output grating couplers of the AWG using DVS-BCB adhesive bonding. The complete device with AWG and detectors has a footprint of only 2 mm(2) while the measured accuracy and resolution of the detected wavelength is better than 20pm. PMID:25401880

Muneeb, M; Ruocco, A; Malik, A; Pathak, S; Ryckeboer, E; Sanchez, D; Cerutti, L; Rodriguez, J B; Tournié, E; Bogaerts, W; Smit, M K; Roelkens, G

2014-11-01

211

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

212

Analytical model of single-X-ray photon counting pixel-array detectors  

NASA Astrophysics Data System (ADS)

Single-X-ray-photon counting pixel array detectors are now widely used on synchrotron beamlines for X-ray diffraction and imaging experiments. Efforts have been carried out in the recent years to extend X-ray detector system analysis to include charge-sharing effects and characteristic X-ray re-absorption on image quality parameters such as MTF, NPS and DQE. These efforts led to the formulation of an analytical model of single-X-ray-photon counting pixel array detectors which is presented in this contribution to the IWORID-2013 conference. This model links together imaging and spectroscopic performance of pixel array detectors. It provides a framework for optimising the design of single-energy threshold, multiple-energy thresholds and energy-sensitive pixel array detectors. This analytical model is applied to typical silicon- and CdTe-based pixel sensor geometries associated to single-X-ray processing read-out electronics.

Marchal, J.; McGrath, J.; Medjoubi, K.

2014-03-01

213

Development of the 40-120 Micron Detector Array for AIRES  

NASA Astrophysics Data System (ADS)

We are developing a 16x24 detector array to cover the 40-120 ? m wavelength range for AIRES, the Airborne InfraRed Echelle Spectrometer for SOFIA. Here we describe the design, fabrication, and assembly of a 2x24 prototype module for this array, and the other components required for the full array. The detectors are discrete bulk Ge:Sb photoconductors with 1 mm interelectrode separation. The array pitch is 2 mm. Each detector is housed in an integrating cavity, optically fed by a straight-sided light cone. Two 1x32 SBRC 190 cryogenic multiplexers are mounted in close proximity to the detectors in each 2x24 module, to transmit the detector signals to warm electronics outside the cryostat. The system is being designed to reach background-limited performance with a resolving power of 104 at 100 ? m on SOFIA. Design considerations and existing hardware will be described.

Erickson, E. F.; Dotson, J. L.; Mason, C. G.; Koerber, C. T.; Prasad, A. K.; Witteborn, F. C.; Rabanus, D.; Young, E. T.

2000-12-01

214

Delta-Doped CCDs as Detector Arrays in Mass Spectrometers  

NASA Technical Reports Server (NTRS)

In a conventional mass spectrometer, charged particles (ions) are dispersed through a magnetic sector onto an MCP at an output (focal) plane. In the MCP, the impinging charged particles excite electron cascades that afford signal gain. Electrons leaving the MCP can be read out by any of a variety of means; most commonly, they are post-accelerated onto a solid-state detector array, wherein the electron pulses are converted to photons, which, in turn, are converted to measurable electric-current pulses by photodetectors. Each step in the conversion from the impinging charged particles to the output 26 NASA Tech Briefs, February 2007 current pulses reduces spatial resolution and increases noise, thereby reducing the overall sensitivity and performance of the mass spectrometer. Hence, it would be preferable to make a direct measurement of the spatial distribution of charged particles impinging on the focal plane. The utility of delta-doped CCDs as detectors of charged particles was reported in two articles in NASA Tech Briefs, Vol. 22, No. 7 (July 1998): "Delta-Doped CCDs as Low-Energy-Particle Detectors" (NPO-20178) on page 48 and "Delta- Doped CCDs for Measuring Energies of Positive Ions" (NPO-20253) on page 50. In the present developmental miniature mass spectrometers, the above mentioned miniaturization and performance advantages contributed by the use of delta-doped CCDs are combined with the advantages afforded by the Mattauch-Herzog design. The Mattauch- Herzog design is a double-focusing spectrometer design involving an electric and a magnetic sector, where the ions of different masses are spatially separated along the focal plane of magnetic sector. A delta-doped CCD at the focal plane measures the signals of all the charged-particle species simultaneously at high sensitivity and high resolution, thereby nearly instantaneously providing a complete, high-quality mass spectrum. The simultaneous nature of the measurement of ions stands in contrast to that of a scanning mass spectrometer, in which abundances of different masses are measured at successive times.

Nikzad, Shouleh; Jones, Todd; Jewell, April; Sinha, Mahadeva

2007-01-01

215

Evaluation and optimization of NIR HgCdTe avalanche photodiode arrays for adaptive optics and interferometry  

NASA Astrophysics Data System (ADS)

The performance of the current high speed near infrared HgCdTe sensors operating in fringe trackers, wavefront sensors and tip-tilt sensors is severely limited by the noise of the silicon readout interface circuit (ROIC), even if state-of-the- art CMOS designs are used. A major improvement can only be achieved by the amplification of the photoelectron signal directly at the point of absorption by means of avalanche gain inside the infrared pixel. Unlike silicon, HgCdTe offers noiseless avalanche gain. This has been verified with the LPE grown 320x256 pixel ?c=2.5 ?m HgCdTe eAPD arrays from SELEX both on a prototype ROIC called SWALLOW and on a newly developed ROIC, specifically designed for AO applications, called SAPHIRA. The novel features of the new SAPHIRA ROIC, which has 32 parallel video channels operating at 5 MHz, will be described, together with the new high speed NGC data acquisition system. Performance results will be discussed for both ROICs. The LPE material on the SWALLOW prototype was excellent and allowed operation at an APD gain as high as 33. Unfortunately, the LPE material of the first devices on the SAPHIRA ROIC suffers from problems which are now understood. However, due to the excellent performance of the SAPHIRA ROIC even with the limitations of present HgCdTe material, it is possible with simple double correlated sampling to detect test patterns with signal levels of 1 electron. An outlook will be given on further developments of heterojunctions grown by MOVPE, which eventually may replace eAPD arrays grown by LPE.

Finger, Gert; Baker, Ian; Alvarez, Domingo; Ives, Derek; Mehrgan, Leander; Meyer, Manfred; Stegmeier, Joerg; Thorne, Peter; Weller, Harald J.

2012-07-01

216

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

NASA Technical Reports Server (NTRS)

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.

Timothy, J. G.

1984-01-01

217

Cosmic-Ray-Air Shower Timing Experiment: Performance of a Mini Array Detector  

NASA Astrophysics Data System (ADS)

A small-scale, detector utilizing the measurement of finite thickness of airshowers has been developed and operated on the ro of of the physics building, Gauhati University (Guwahati, Assam, India), since 1996. The experiment is based on extensive work of Linsley with such detectors. The array consists of eight plastic scintillation detectors (BC416, size: 50 × 50 × 5cm3 ) each viewed by fast photomultiplier tubes (PMTs, type: Thorn EMI 9807B) to look at showers from 1017 eV to 1019 eV energy. Performance and end results of the detector array will be discussed.

Bezboruah, Tulshi

2003-07-01

218

Microuidic integration on detector arrays for absorption and uorescence micro-spectrometers  

E-print Network

, which provide hermetic seals to silicon dioxide and allow sensitive absorption and ¯uorescent-channel spectrometers de®ned on complementary metal oxide semiconductor (CMOS) silicon detector arrays can be used

Quake, Stephen R.

219

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

DOEpatents

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.

Enke, Christie

2013-02-19

220

High-performance liquid chromatographic determination of acetyl-11-keto-?-boswellic acid, a novel pentacyclic triterpenoid, in plasma using a fluorinated stationary phase and photodiode array detection: Application in pharmacokinetic studies  

Microsoft Academic Search

A rapid, sensitive and selective HPLC separation with photodiode array detection was developed for the analysis of the novel pentacyclic triterpenoid acetyl-11-keto-?-boswellic acid. Complete baseline separation of acetyl-11-keto-?-boswellic acid from the corresponding isomer acetyl-11-keto-?-boswellic acid was achieved on a fluorinated stationary phase. The standard curve was linear from 0.98nmol\\/l to 196nmol\\/l acetyl-11-keto-?-boswellic acid. The compound was isolated from chick embryonic

Berthold Büchele; Waltraud Zugmaier; Felicitas Genze; Thomas Simmet

2005-01-01

221

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

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

222

MINI-ARRAYS OF DETECTORS FOR THE STUDY OF COSMIC-RAY AIR SHOWERSê  

Microsoft Academic Search

Primary cosmic rays entering the Earth's atmosphere, initiate Extensive Air Showers (EAS). Mini-arrays of detectors making use of the Linsley effect measure the spread of the arrival times in particle samples and make it possible to estimate the distance to the shower axis. The potential of the mini-arrays is appraised for their use in coincidence with the electromagnetic calorimeter WILLI

A. A. RADU; I. M. BRANCUS; O. BROSCARU; D. FELEA; B. MITRICA

223

Linearity and resolution of photodiodes  

SciTech Connect

Measurements are reported of the resolution and linearity of Hamamatsu S1337 Photodiodes mounted on a NaI crystal and exposed to electron energy deposits of up to 80 GeV. The results indicate that these diodes can replace photomultipliers in high-light-yield detectors such as NaI and BGO, when operated in multi-element, compact assemblies in the presence of a magnetic field.

van Driel, M.A.; Sens, J.C.

1983-10-01

224

Infrared detectors and arrays; Proceedings of the Meeting, Orlando, FL, Apr. 6, 7, 1988  

Microsoft Academic Search

The papers contained in this volume provide an overview of recent advances in theoretical and experimental research related to IR detector materials and arrays. The major subject areas covered include IR Schottky barrier silicide arrays, HdCdTe developments, SPRITE technology, superlattice or bandgap-engineered devices, extrinsic silicon technology, indium antimonide technology, and pyroelectric arrays. Papers are presented on time division multiplexed time

Eustace L. Dereniak

1988-01-01

225

Development of focal plane arrays with hot electron bolometer heterodyne detectors for 3 to 10 THz  

Microsoft Academic Search

Broadband tunable, hot electron bolometer (HEB) heterodyne detectors with receiver noise temperatures of the order of 10×hf\\/k in the frequency range 3 THz to 10 THz are required for future space systems. The HEB detectors have to be configured in focal plane arrays (FPA) with many elements (hundreds). We discuss the feasibility of such FPAs, especially the expected performance of

Sigfrid Yngvesson; Eyal Gerecht; John Nicholson; Fernando Rodriguez-Morales; Dazhen Gu; Xin Zhao; Jerry Waldman; Thomas Goyette; Erik Kollberg

2004-01-01

226

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...

227

Study and Testing of a Pixel Array Detector for Electron Microscope Application  

E-print Network

Study and Testing of a Pixel Array Detector for Electron Microscope Application Thomas A Caswell to the detectors and the electron microscopes. Adapting the PAD for us in an electron microscope is a project of the experimental work the microscope was operated by Peter Ercius. He was also instrumental in my introduction

Gardel, Margaret

228

I-V and noise performance in MWIR to VLWIR large area Hg1-xCdxTe photodiodes  

NASA Astrophysics Data System (ADS)

The National Polar-orbiting Operational Environmental Satellite System (NPOESS), is overseen by the Integrated Program Office (IPO), a joint effort of the Department of Defense, Department of Commerce and NASA. One of the instruments on the NPOESS satellite is the Cross-track Infrared Sounder (CrIS) instrument. CrIS is a Fourier Transform interferometric infrared (FTIR) sensor used to measure earth radiance at high spectral resolution to derive pressure, temperature, and moisture profiles of the atmosphere from the ground on up. Each CrIS instrument contains three different cutoff wavelength (?c)focal plane modules (FPMs): an SWIR FPM [?c(98 K) ~ 5 mm], MWIR FPM [?c(98 K) ~ 9 mm] and a LWIR FPM [?c(81 K) ~ 15.5 mm]. There are nine large (850 mm diameter) photodiodes per FPM, the nine detectors being arranged in a 3 x 3 array. The nine detectors are placed under tight tolerances in the X, Y, and Z dimensions. The steps involved in the transfer of photodiodes as part of a newly fabricated wafer to the mounting of the photodiodes on the FPM involves many processing steps including a significant amount of dicing, cleaning, wire bonding and baking at elevated temperatures. Quantum efficiency and 1/f noise in Hg1-xCdxTe photodiodes are critical parameters that limit the sensitivity of infrared sounders. The ratio ?, defined as the noise current in unit bandwidth in(f = 1 Hz, Vd, ?f = 1 Hz) to the dark current Id(Vd), that is, ? = in/Id is one of the parameters used to select photodiodes for placement in FPMs. ? is equivalent to ??H/N that appears in the well-known Hooge expression. For the sixty-one, ?c ~ 9 ?m photodiodes measured at 60 mV reverse bias and at 98 K, the average value of ?dark = 1.3 x 10-4 in the dark and ?PHOTO = in/IPHOTO is ~ 2 x 10-6 under illuminated conditions. These values of ? are a factor of two lower than that reported previously. The ?c ~ 15.5 ?m photodiodes have average ?dark = 1.3 x 10-5 with the highest performance, diffusion current limited photodiodes having values of ?dark in the mid 10-6 range. All of the 850 ?m diameter, ?c ~ 15.5 ?m photodiodes measured have excess low frequency noise, with the best performers having in(f = 100 Hz, Vd =-60 mV , ?f = 1 Hz) ~ 2 x 10-11 A/Hz1/2 and the best photodiode ?dark = 3.92 x 10-6. I-V measurements, noise, and visual inspections are performed at several steps in the photodiodes manufacturing process. It was observed, following FPM fabrication, photodiode dark current and noise had increased from the initial pre-mounting leadless chip carrier (LCC) measurements for some of the nine photodiodes. The performance degradation observed led to an investigation into the cause (baking at elevated temperatures, mechanical handling, electrical stress etc.) of photodiode degradation that occurred between LCC and FPM testing. Correlations between I-V, noise and surface visual defects have been performed on some ?c ~ 15.5 mm photodiodes. This paper outlines the results of the study, correlating the electrical performance observed to visual defects on the surface and to defects seen following cross sectioning of degraded photodiodes. In addition, other lessons learned and the corrective actions implemented that led to the successful manufacture of SWIR, MWIR and LWIR large photodiodes from the material growth to insertion into and successful demonstration of flight FPMs for the CrIS program are described.

D'Souza, A. I.; Stapelbroek, M. G.; Dolan, P. N.; Wijewarnasuriya, P. S.; Boehmer, E.; Smith, D. S.; Ehlert, J. C.; Andrews, J. E.

2005-05-01

229

Integrated filter and detector array for spectral imaging  

NASA Technical Reports Server (NTRS)

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.

Labaw, Clayton C. (inventor)

1992-01-01

230

Multi-anode microchannel arrays - New detectors for imaging and spectroscopy in space  

NASA Technical Reports Server (NTRS)

Consideration is given to the construction and operation of multi-anode microchannel array detector systems having formats as large as 256 x 1024 pixels. Such arrays are being developed for imaging and spectroscopy at soft X-ray, ultraviolet and visible wavelengths from balloons, sounding rockets and space probes. Both discrete-anode and coincidence-anode arrays are described. Two types of photocathode structures are evaluated: an opaque photocathode deposited directly on the curved-channel MCP and an activated cathode deposited on a proximity-focused mesh. Future work will include sensitivity optimization in the different wavelength regions and the development of detector tubes with semitransparent proximity-focused photocathodes.

Timothy, J. G.; Bybee, R. L.

1983-01-01

231

Performance of superconducting nanowire single-photon detector with the fan coupling antenna array  

NASA Astrophysics Data System (ADS)

The performance of superconducting nanowire single-photon detector (SNSPD) involving niobium nitride with the fan coupling antenna array is analyzed. The SNSPD has a high detection efficiency and counting rate. Hydrogen silsesquioxane and niobium nitride are filled in the gold grating deposited on the substrate in which the fan coupling antenna arrays are embedded. By changing the position of the fan coupling antenna array, the maximum area of optical intensity is obtained and the photon collection efficiency is increased by 26.5 times. The detection efficiency of SNSPD is improved without changing the detection speed. These parameters are important for designing a practical single-photon detector.

Wang, Yu-Jue; Ding, Tian; Ma, Hai-Qiang; Jiao, Rong-Zhen

2014-06-01

232

Solar-blind AlGaN 256x256 p-i-n detectors and focal plane arrays  

NASA Astrophysics Data System (ADS)

This paper reports the development of aluminum-gallium nitride (AlGaN or Al xGa 1-xN) photodiode technology for high-operability 256×256 hybrid Focal Plane Arrays (FPAs) for solar-blind ultraviolet (UV) detection in the 260-280 nm spectral region. These hybrid UV FPAs consist of a 256×256 back-illuminated AlGaN p-i-n photodiode array, operating at zero bias voltage, bump-mounted to a matching 256×256 silicon CMOS readout integrated circuit (ROIC) chip. The unit cell size is 30×30 ?m2. The photodiode arrays were fabricated from multilayer AlGaN films grown by MOCVD on 2" dia. UV-transparent sapphire substrates. Improvements in AlGaN material growth and device design enabled high quantum efficiency and extremely low leakage current to be achieved in high-operability 256×256 p-i-n photodiode arrays with cuton and cutoff wavelengths of 260 and 280 nm, placing the response in the solar-blind wavelength region (less than about 280 nm) where solar radiation is heavily absorbed by the ozone layer. External quantum efficiencies (at V=0, 270 nm, no antireflection coating) as high as 58% were measured in backilluminated devices. A number of 256×256 FPAs, with the AlGaN arrays fabricated from films grown at three different facilities, achieved response operabilities as high as 99.8%, response nonuniformities (?/?) as low as 2.5%, and zero-bias resistance median values as high as 1×10 16 ohm, corresponding to R 0A products of 7×10 10 ohm-cm2. Noise Equivalent Irradiance (NEI) data were measured on these FPAs. Median NEI values at 1 Hz are 250-500 photons/pixel-s, with best-element values as low as 90 photons/pixel-s at 1 Hz.

Reine, M. B.; Hairston, A.; Lamarre, P.; Wong, K. K.; Tobin, S. P.; Sood, A. K.; Cooke, C.; Pophristic, M.; Guo, S.; Peres, B.; Singh, R.; Eddy, C. R., Jr.; Chowdhury, U.; Wong, M. M.; Dupuis, R. D.; Li, T.; DenBaars, S. P.

2006-02-01

233

Solar-blind AlGaN 256×256 p-i-n detectors and focal plane arrays  

NASA Astrophysics Data System (ADS)

This paper reports the development of aluminum-gallium nitride (AlGaN or Al xGa 1-xN) photodiode technology for high-operability 256×256 hybrid Focal Plane Arrays (FPAs) for solar-blind ultraviolet (UV) detection in the 260-280 nm spectral region. These hybrid UV FPAs consist of a 256×256 back-illuminated AlGaN p-i-n photodiode array, operating at zero bias voltage, bump-mounted to a matching 256×256 silicon CMOS readout integrated circuit (ROIC) chip. The unit cell size is 30×30 ?m2. The photodiode arrays were fabricated from multilayer AlGaN films grown by MOCVD on 2" dia. UV-transparent sapphire substrates. Improvements in AlGaN material growth and device design enabled high quantum efficiency and extremely low leakage current to be achieved in high-operability 256×256 p-i-n photodiode arrays with cuton and cutoff wavelengths of 260 and 280 nm, placing the response in the solar-blind wavelength region (less than about 280 nm) where solar radiation is heavily absorbed by the ozone layer. External quantum efficiencies (at V=0, 270 nm, no antireflection coating) as high as 58% were measured in back-illuminated devices. A number of 256×256 FPAs, with the AlGaN arrays fabricated from films grown at three different facilities, achieved response operabilities as high as 99.8%, response nonuniformities (?/?) as low as 2.5%, and zero-bias resistance median values as high as 1×10 16 ohm, corresponding to R0A products of 7×10 10 ohm-cm2. Noise Equivalent Irradiance (NEI) data were measured on these FPAs. Median NEI values at 1 Hz are 250-500 photons/pixel-s, with best-element values as low as 90 photons/pixel-s at 1 Hz.

Reine, M. B.; Hairston, A.; Lamarre, P.; Wong, K. K.; Tobin, S. P.; Sood, A. K.; Cooke, C.; Pophristic, M.; Guo, S.; Peres, B.; Singh, R.; Eddy, C. R. _Jr., Jr.; Chowdhury, U.; Wong, M. M.; Dupuis, R. D.; Li, T.; DenBaars, S. P.

2006-02-01

234

Modulation transfer function of a triangular pixel array detector.  

PubMed

The modulation transfer function (MTF) is the main parameter that is used to evaluate image quality in electro-optical systems. Detector sampling MTF in most electro-optical systems determines the cutoff frequency of the system. The MTF of the detector depends on its pixel shape. In this work, we calculated the MTF of a detector with an equilateral triangular pixel shape. Some new results were found in deriving the MTF for the equilateral triangular pixel shape. PMID:25121458

Karimzadeh, Ayatollah

2014-07-01

235

Development of uncooled focal plane detector arrays for smart IR sensors  

NASA Astrophysics Data System (ADS)

This paper reports on the development of silicon microbolometer uncooled IR focal plane detector arrays at the Defence Science and Technology Organization (DSTO), in collaboration with the National Defence Research Establishment (FOA). The detector arrays were designed by Electro-optic Sensor Design, which also provided specialist scientific advice on array fabrication. Detector arrays are prepared by monolithic processing at DSTO, using surface micromachining to achieve thermal isolation, and are integrated on-chip with a CMOS signal conditioning and readout microcircuit designed by FOA. The CMOS circuit incorporates 16-bit analog-to-digital conversion, and is described in more detail in an accompanying paper presented. The ultimate objective is to develop 'smart' focal plane arrays which have on-chip signal processing functions, giving a capability for decision making such as automatic target detection. The silicon microbolometer technology described in the paper was invented at DSTO, and is representative of core technology employed in many initiatives world-wide. A brief overview will be given of theoretical considerations which influence detector array design, followed by an outline of recent developments in array processing.

Liddiard, Kevin C.; Reinhold, Olaf; Ringh, Ulf; Jansson, Christer

1997-11-01

236

Trigger and Aperture of the Surface Detector Array of the Pierre Auger Observatory  

E-print Network

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 $3\\times 10^{18}$ eV, for all zenith angles between 0$^\\circ$ and 60$^\\circ$, 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.

Abraham, J; Aglietta, M; Aguirre, C; Ahn, E J; Allard, D; Allekotte, I; Allen, J; Alvarez-Muñiz, J; Ambrosio, M; Anchordoqui, L; Andringa, S; Anzalone, A; Aramo, C; Arganda, E; Argirò, S; Arisaka, K; Arneodo, F; Arqueros, F; Asch, T; Asorey, H; Assis, P; Aublin, J; Ave, M; Avila, G; Bäcker, T; Badagnani, D; Barber, K B; Barbosa, A F; Barroso, S L C; Baughman, B; Bauleo, P; Beatty, J J; Beau, T; Becker, B R; Becker, K H; Bellétoile, A; Bellido, J A; BenZvi, S; Berat, C; Bernardini, P; Bertou, X; Biermann, P L; Billoir, P; Blanch-Bigas, O; Blanco, F; Bleve, C; Blümer, H; Bohá?ová, 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; Carvalho, W; Castellina, A; Catalano, O; Cazon, L; Cester, R; Chauvin, J; Chiavassa, A; Chinellato, J A; Chou, A; Chudoba, J; Chye, J; Clay, R W; Colombo, E; Conceição, R; Connolly, B; Contreras, F; 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; Junior, W J M de Mello; Neto, J R T de Mello; De Mitri, I; de Souza, V; de Vries, K D; Decerprit, G; del Peral, L; Deligny, O; Della Selva, A; Fratte, C Delle; Dembinski, H; Di Giulio, C; Diaz, J C; Diep, P N; Dobrigkeit, C; D'Olivo, J C; Dong, P N; Dorofeev, A; Anjos, J C dos; Dova, M T; D'Urso, D; Dutan, I; DuVernois, M A; Engel, R; Erdmann, M; Escobar, C O; Etchegoyen, A; Luis, P Facal San; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Ferrer, F; Ferrero, A; Fick, B; Filevich, A; Filip?i?, A; Fleck, I; Fliescher, S; Fracchiolla, C E; Fraenkel, E D; Fulgione, W; Gamarra, R F; Gambetta, S; García, B; Gámez, D García; 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; Albarracin, F Gomez; Berisso, M Gómez; Gonçalves, P; Amaral, M Gonçalves do; 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; Gutiérrez, J; Hague, J D; Halenka, V; Hansen, P; Harari, D; Harmsma, S; Harton, J L; Haungs, A; Healy, M D; Hebbeker, T; Hebrero, G; Heck, D; 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; Kaducak, M; Kampert, K H; Karova, T; Kasper, P; Kégl, B; Keilhauer, B; 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; de Oliveira, M A Leigui; Lemiere, A; Letessier-Selvon, A; Leuthold, M; Lhenry-Yvon, I; López, R; Agüera, A Lopez; Louedec, K; Bahilo, J Lozano; Lucero, A; Lyberis, H; Maccarone, M C; Macolino, C; Maldera, S; Mandat, D; Mantsch, P; Mariazzi, A G; Maris, I C; Falcon, H R Marquez; Martello, D; Bravo, O Martínez; Mathes, H J; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mazur, P O; McEwen, M; McNeil, R R; Medina-Tanco, G; Melissas, M; Melo, D; Menichetti, E; Menshikov, A; Meyhandan, R; Micheletti, M I; Miele, G; Miller, W; Miramonti, L; Mollerach, S; Monasor, M; Ragaigne, D Monnier; Montanet, F; Morales, B; Morello, C; Moreno, J C; Morris, C; Mostafá, M; Moura, C A; Mueller, S; Muller, M A; Mussa, R; Navarra, G; Navarro, J L; Navas, S; Necesal, P; Nellen, L; Newman-Holmes, C; Newton, D; 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; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Parente, G; Parizot, E; Parlati, S; Pastor, S; Patel, M; Paul, T; Pavlidou, V; Payet, K; Pech, M; P?kala, J; 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; Pinto, T; Pirronello, V; Pisanti, O; Platino, M; Pochon, J; 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; Rivière, C; Rizi, V; Robledo, C; Rodriguez, G; Martino, J Rodriguez; Rojo, J Rodriguez; 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; Santos, E M; Sarazin, F; Sarkar, S; Sato, R; Scharf, N; Scherini, V; Schieler, H; Schiffer, P; Schmidt, A; Schmidt, F; Schmidt, T

2011-01-01

237

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

SciTech Connect

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 m{sup 2} cross section and five smaller ones of 1.86 m{sup 2} cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m{sup 2}. 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)

Perez, E.; Conde, R.; Martinez, O.; Murrieta, T.; Salazar, H. [Facultad de Ciencias Fisico-Matematicas, BUAP, Puebla Pue., 72570 (Mexico); Villasenor, L. [Institute of Physics and Mathematics, Universidad Michoacana, Edificio C3, Ciudad Universitaria, Morelia, Mich., 58040 (Mexico)

2006-09-25

238

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

NASA Astrophysics Data System (ADS)

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).

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

2006-09-01

239

A Medium-Format, Mixed-Mode Pixel Array Detector for Kilohertz X-ray Imaging  

NASA Astrophysics Data System (ADS)

An x-ray pixel array detector (PAD) capable of framing up to 1 kHz is described. This hybrid detector is constructed from a 3-side buttable, 128×128 pixel module based upon the mixed-mode pixel array detector (MMPAD) chip developed jointly by Cornell and Area Detector Systems Corporation (Poway, CA). The chip uses a charge integrating front end for a high instantaneous count rate yet with single photon sensitivity. In-pixel circuitry utilizing a digital overflow counter extends the per frame dynamic range to >4×107 x-rays/pixel. Results are shown from a base configuration of a 2×3 module array (256×384 pixels).

Tate, M. W.; Chamberlain, D.; Green, K. S.; Philipp, H. T.; Purohit, P.; Strohman, C.; Gruner, S. M.

2013-03-01

240

Design and Performance of the Astro-E/XRS Microcalorimeter Array and Anti-Coincidence Detector  

NASA Technical Reports Server (NTRS)

The XRS instrument has an array of 32 micro-calorimeters 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 9 eV at 3 keV and 11 eV at 6 keV. We will discuss the basic physical parameters of this array, including the array layout, thermal conductance of the link to the heat sink, operating temperature, thermistor size, absorber choice, and means of attaching the absorber to the thermistor bearing element. We will present representative performance data, though a more detailed presentation of the results of the instrument calibration is presented elsewhere in these proceedings. 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 in conjunction with the array.

Stahle, C. K.; Audley, M. D.; Boyce, K. R.; Brekosky, R. P.; Fujimoto, R.; Gendreau, K. C.; Gygax, J. D.; Ishisaki, Y.; Kelley, R. L.; McClanahan, R. A.

1999-01-01

241

Growth of InAs/GaSb short-period superlattices for high-resolution mid-wavelength infrared focal plane array detectors  

NASA Astrophysics Data System (ADS)

InAs/GaSb short-period superlattices (SLs) with a broken gap type-II band alignment are investigated for the fabrication of photovoltaic pin-photodetectors on GaSb substrates. The structures were grown by molecular beam epitaxy using valved cracker cells for arsenic and antimony. Effective bandgap and strain in the SL were adjusted by varying the thickness of the InAs and GaSb layers in the SL and the controlled formation of InSb-like or GaAs-like bonds at the interfaces. MBE growth conditions were investigated and optimized in order to achieve good morphological, electrical and optical properties. IR-photodiodes with a cut-off wavelength of 5.4 ?m reveal quantum efficiencies around 30% and detectivity values exceeding 10 13 Jones at 77 K. A focal plane array camera with 256×256 detector elements and 40 ?m pitch based on InAs/GaSb short-period SLs was fabricated for the first time. The camera system reveals an excellent thermal resolution with a noise equivalent temperature difference below 12 mK for an integration time of 5 ms using f/2 optics. The detector performance, comparable with state of the art mercury-cadmium-telluride IR detectors, makes this material system very interesting for the fabrication of advanced thermal imaging systems.

Walther, M.; Schmitz, J.; Rehm, R.; Kopta, S.; Fuchs, F.; Fleißner, J.; Cabanski, W.; Ziegler, J.

2005-05-01

242

Imaging by time-tagging photons with the multi-anode microchannel array detector system  

NASA Technical Reports Server (NTRS)

The capability and initial use of the Multi-Anode Microchannel Array (MAMA) detector in the time-tag mode is reported. The detector hardware currently in use consists of a visible-light detector tube with a semitransparent photocathode proximity-focused to a high-gain curved-channel microchannel plate MCP. The photoevents are detected by a (256 x 1024)-pixel coincidence-anode array with pixel dimensions of 25 x 25 microns connected to charge-sensitive amplifiers and event-detection circuitry. In the time-lag mode, the detector delivers the pixel address and the time of arrival for each detected photon to an accuracy of 10 microns. The maximum count rate is limited by the speed of data-acquisition hardware. The MAMA detector in the time-lag mode is currently being evaluated in programs of astrometry and speckle imaging.

Timothy, J. G.; Morgan, J. S.

1986-01-01

243

An evaluation of a two-dimensional array detector for high resolution PET.  

PubMed

A two-dimensional array detector system, consisting of 4x8 matrices of bismuth germanate (BGO) crystals coupled to four photomultipliers, was evaluated. Coincidence timing resolution of a pair of array detectors was 6.1 ns FWHM and 11.3 ns FWTM. Energy resolution per individual crystal ranged from 16.8 to 24.1% FWHM at 511 keV for an amplitude variation of a factor of 2.8. The signals from the photomultipliers were summed pairwise, the pairs in each dimension subtracted, and the differences divided by the amplitude of the signal summed from all four photomultipliers. The resulting two-pulse-height spectra contained peaks corresponding to the row or column containing the detector of interaction. Six conditions of detector identification were tested. The correct identification of detector ranged from 76% to 87% of the events. The largest single factor in improving crystal identification and spatial resolution was energy discrimination. PMID:18230478

Dahlbom, M; Hoffman, E J

1988-01-01

244

Research on hybrid device of Si microlens arrays with long focus and IR detector arrays  

Microsoft Academic Search

A new method, named step simulation, is proposed to fabricate refractive 128×128 element Si microlens (MLS) arrays for hybrid integration with PtSi IR Focal Plane Arrays (FPAs). By the method, the focal length of rectangle-based multilevel Si MLS arrays is over 1 millimeter, much longer than typical focal length of MLS array fabricated by conventional binary optics Fresnel technique. Si

Chen Sihai; Yi Xinjian; He Miao; Zhang Xinyu

2000-01-01

245

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

NASA Astrophysics Data System (ADS)

Multi-Anode Microchannel Array (MAMA) detector systems with formats of 256 x 1024 pixels and active areas of 6 x 26 square mm are now under evaluation at visible, ultraviolet and soft x-ray wavelengths. Very-large-format versions of the MAMA detectors with formats of 2048 x 2048 pixels and active areas of 52 x 52 square mm are under development for use in the NASA Goddard Space Flight Center's Space Telescope Imaging Spectrograph (STIS). Open-structure versions of these detectors with CsI photocathodes can provide a high-resolution imaging capability at extreme ultraviolet (EUV) and soft x-ray wavelengths and can deliver a maximum count rate from each array in excess of 1 million counts s-1. In addition, these detector systems have the unique capability to determine the arrival time of a detected photon to an accuracy of 100 ns or better. The construction, mode-of-operation and performance characteristics of the MAMA detectors are described and the program for the development of the very-large-format detectors is outlined.

Timothy, J. G.

1986-07-01

246

Extending the Astronomical Application of Photon Counting HgCdTe Linear Avalanche Photo-Diode Arrays to Low Background Space Observations.  

NASA Astrophysics Data System (ADS)

The high quantum efficiency and very low dark current, together with the ability to set the wavelength cutoff from one to far beyond 5.5 microns, of large format HAWAII HgCdTe arrays have already made them the workhorse for NASA space astronomy (and related) observations in the 1 to 5.5 micron infrared. They have performed outstandingly on Hubble Wide Field Camera 3 and WISE (and also Deep Impact/EPOXI and OCO-2) and are crucial to the two major NASA Astrophysics missions, JWST and WFIRST, and to Euclid. The proposed investigation seeks to extend these benefits to the most demanding observations those that seek to wring information from only a few photons (starved due to either the intrinsic faintness of the source or the need for high spectral or time resolution) or to discriminate a weak signature against a bright source. We will characterize, and optimize for space astronomy observations, the unique linear avalanche properties of HgCdTe photo-diodes (HgCdTe L-APDs) that allow noiseless (i.e. faithfully preserves the Poisson statistics of the incoming photons) avalanche multiplication of individual photo-electrons. 2.5 micron HgCdTe L-APD technology, developed for infrared eye-safe LIDAR and range gated imaging, is already benefiting infrared wavefront sensing for ground based adaptive optics. In HgCdTe the L-APD gain and the onset voltage for tunneling current are exponential functions of bandgap while also varying with cryogenic operating temperature. The unique HgCdTe bandgap engineering that allows tuning of the cutoff wavelength can be used to critically improve avalanche performance for specific applications. We will thoroughly evaluate avalanche performance at several representative bandgaps so as to allow model prediction of performance over the critical 1 to 5 micron spectral interval. The proposed investigation will hybridize modest 32x32 arrays of HgCdTe L-APDs to photon counting readouts already developed under another award and characterize their infrared photon counting performance at the low and ultra-low backgrounds required for NASA space astronomy missions. Specifically this will involve 1) Measuring the gain normalized dark count rate and avalanche gain of 2.5, 3.3 and 4 micron cutoff HgCdTe at cryogenic temperatures from 30 to 80 K and bias voltages up to 20 V, 2) Using these results to validate and refine models of avalanche gain along with generation- recombination and surface trap induced tunneling current in L-APD HgCdTe and, 3) Modeling the gain normalized dark count rate, surface tunneling current and avalanche gain of 2 to 5 micron cutoff HgCdTe L-APD arrays for astrophysics and other NASA missions. The overall objective of the investigation is to develop the tools to identify the sweet spot in bandgap and cryogenic operating temperature for each specific NASA astrophysics mission and to accurately predict ultimate performance. HgCdTe L-APD technology offers to NASA the ultimate performance for space astronomy in photon starved applications such as: 1) ultra-low background, extra- Zodiacal imaging and faint object spectroscopy from elliptical orbits beyond the asteroid belt with missions such as Extra-Zodiacal Explorer, 2) spectroscopy of the faintest O/IR sources from near earth and L-2 orbit at moderate to high resolution and, 3) time domain astronomy observations (photometric or spectral variations at frequencies above 1 Hz) of sources as diverse as close binaries, accretion disks, compact objects etc. HgCdTe L- APD arrays have the potential to enable new classes of missions and to bring critical observations within reach of the capabilities of the NASA SMD Astrophysics Explorer program. As they utilize the same mature TRL base as the large format JWST HgCdTe arrays, requiring only qualification of n-on-p material operated at higher bias voltages, the path to flight qualification is unusually direct.

Hall, Donald

247

Integrated treatment of detector arrays for source tracking.  

SciTech Connect

Illicit radioactive sources can potentially appear in a wide range of public venues. One element in a plan for managing such sources involves searching for them in venues at risk and tracking them in real time when they are detected. A treatment of source tracking using multiple directional detectors in a probabilistic framework is given. The performance of a prototype directional detector based on these methods was characterized in the laboratory. Instances where the performance of a directional detector is not immune to the effects of shielding are identified.

Thomas, J.; Vilim, R.; Klann, R. (Nuclear Engineering Division)

2011-07-01

248

High-resolution pulse-counting array detectors for imaging and spectroscopy at ultraviolet wavelengths  

NASA Astrophysics Data System (ADS)

The performance characteristics of multianode microchannel array (MAMA) detector systems which have formats as large as 256 x 1024 pixels and which have application to imaging and spectroscopy at UV wavelengths are evaluated. Sealed and open-structure MAMA detector tubes with opaque CsI photocathodes can determine the arrival time of the detected photon to an accuracy of 100 ns or better. Very large format MAMA detectors with CsI and Cs2Te photocathodes and active areas of 52 x 52 mm (2048 x 2048 pixels) will be used as the UV solar blind detectors for the NASA STIS.

Timothy, J. Gethyn; Bybee, Richard L.

1986-01-01

249

A cooled avalanche photodiode with high photon detection probability  

NASA Technical Reports Server (NTRS)

An avalanche photodiode has been operated as a photon-counting detector with 2 to 3 times the sensitivity of currently-available photomultiplier tubes. APD (avalanche photodiodes) detection probabilities that exceed 27% and approach 50% have been measured at an optimum operating temperature which minimizes noise. The sources of noise and their dependence on operating temperature and bias voltage are discussed.

Robinson, D. L.; Metscher, B. D.

1986-01-01

250

Integrating 128 element InSb array - Recent results. [for spaceborne infrared spectrometers  

NASA Technical Reports Server (NTRS)

There has been a continuing evolution toward larger arrays of infrared detectors, and the technology base derived from the Galileo Near Infrared Mapping Spectrometer (NIMS) has been expanded to linear arrays including from 128 to 512 elements. This advance is based on the commercial availability of high-quality InSb photodiodes and 128/256 element FET switch MUX's (multiplexing elements). The present investigation is concerned with an experimental 128-element linear imager using InSb detectors and silicon MUX for readout. Attention is given to detector array electrical characteristics, the detector readout architecture, noise, and special effects.

Bailey, G.

1982-01-01

251

A position sensitive gamma-ray detector based on silicon drift detectors coupled to scintillators for application in the MEGA Compton telescope  

Microsoft Academic Search

An array of gamma-ray detectors based on silicon drift detectors (SDD) coupled to thallium activated cesium iodide (CsI(Tl)) scintillating crystals is presented. Because of SDDs low output capacitance and the possibility to have the first amplifying stage directly integrated on chip, SDDs show better noise performance than traditional p-i-n photodiodes. The array is read out with custom made ASICs built

M. Marisaldi; C. Labanti; A. Bulgarelli; A. Andritschke; G. Di Cocco; G. Kanbach; F. Gianotti; A. Mauri; E. Rossi; A. Traci; M. Trifoglio

2004-01-01

252

Liquid-helium scintillation detection with germanium photodiodes  

SciTech Connect

Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV ..cap alpha.. particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes.

Luke, P.N.; Haller, E.E.; Steiner, H.M.

1982-05-01

253

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

NASA Technical Reports Server (NTRS)

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.

Kasle, David B.; Horch, Elliott P.

1993-01-01

254

Real-time human identification using a pyroelectric infrared detector array and hidden Markov models  

NASA Astrophysics Data System (ADS)

This paper proposes a real-time human identification system using a pyroelectric infrared (PIR) detector array and hidden Markov models (HMMs). A PIR detector array with masked Fresnel lens arrays is used to generate digital sequential data that can represent a human motion feature. HMMs are trained to statistically model the motion features of individuals through an expectation-maximization (EM) learning process. Human subjects are recognized by evaluating a set of new feature data against the trained HMMs using the maximum-likelihood (ML) criterion. We have developed a prototype system to verify the proposed method. Sensor modules with different numbers of detectors and different sampling masks were tested to maximize the identification capability of the sensor system.

Fang, Jian-Shuen; Hao, Qi; Brady, David J.; Guenther, Bob D.; Hsu, Ken Y.

2006-07-01

255

Description of the Role of Shot Noise in Spectroscopic Absorption and Emission Measurements with Photodiode and Photomultiplier Tube Detectors: Information for an Instrumental Analysis Course  

ERIC Educational Resources Information Center

A description of shot noise and the role it plays in absorption and emission measurements using photodiode and photomultiplier tube detection systems is presented. This description includes derivations of useful forms of the shot noise equation based on Poisson counting statistics. This approach can deepen student understanding of a fundamental…

McClain, Robert L.; Wright, John C.

2014-01-01

256

Development of sensitive long-wave infrared detector arrays for passively cooled space missions  

NASA Astrophysics Data System (ADS)

The near-earth object camera (NEOCam) is a proposed infrared space mission designed to discover and characterize most of the potentially hazardous asteroids larger than 140 m in diameter that orbit near the Earth. NASA has funded technology development for NEOCam, including the development of long wavelength infrared detector arrays that will have excellent zodiacal background emission-limited performance at passively cooled focal plane temperatures. Teledyne Imaging Sensors has developed and delivered for test at the University of Rochester the first set of approximately 10 ?m cutoff, 1024×1024 pixel HgCdTe detector arrays. Measurements of these arrays show the development to be extremely promising: noise, dark current, quantum efficiency, and well depth goals have been met by this technology at focal plane temperatures of 35 to 40 K, readily attainable with passive cooling. The next set of arrays to be developed will address changes suggested by the first set of deliverables.

McMurtry, Craig; Lee, Donald; Beletic, James; Chen, Chi-Yi A.; Demers, Richard T.; Dorn, Meghan; Edwall, Dennis; Fazar, Candice Bacon; Forrest, William J.; Liu, Fengchuan; Mainzer, Amanda K.; Pipher, Judith L.; Yulius, Aristo

2013-09-01

257

Recent results of the energy spectrum and mass composition from Telescope Array Fluorescence Detector  

NASA Astrophysics Data System (ADS)

The Telescope Array experiment is the largest hybrid detector to observe Ultra-High Energy Cosmic Rays in the northern hemisphere. The observation started in November 2007 for Fluorescence Detector (FD) and in March 2008 for Surface Detectors (SD). Here, we present the preliminary results of the energy spectrum and mass composition of the UHECRs measured by the FD and hybrid technique from the Telescope Array three year observations. The energy spectrum measured by the Middle Drum FD station, which is the refurbished HiRes-I detector is consistent with the results from HiRes. The energy spectrum with the two newly constructed FDs and SD is also in good agreement with the result from HiRes, especially for the energy scale. The mass composition study with the slant depth of the maximum shower development (Xmax) is obtained by using the stereo and hybrid analysis. The result of the mass composition is consistent with the proton prediction.

Ikeda, Daisuke

2013-02-01

258

IR Imaging Using Arrays of SiO2 Micromechanical Detectors  

SciTech Connect

In this letter, we describe the fabrication of an array of bimaterial detectors for infrared (IR) imaging that utilize SiO2 as a structural material. All the substrate material underneath the active area of each detector element was removed. Each detector element incorporates an optical resonant cavity layer in the IR absorbing region of the sensing element. The simplified microfabrication process requires only four photolithographic steps with no wet etching or sacrificial layers. The thermomechanical deflection sensitivity was 7.9 10-3 rad/K which corresponds to a noise equivalent temperature difference (NETD) of 2.9 mK. In the present work the array was used to capture IR images while operating at room temperature and atmospheric pressure and no need for vacuum packaging. The average measured NETD of our IR detector system was approximately 200 mK but some sensing elements exhibited an NETD of 50 mK.

Grbovic, Dragoslav [ORNL; Lavrik, Nickolay V [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL; Hunter, Scott Robert [ORNL

2012-01-01

259

Advanced numerical modeling and hybridization techniques for third-generation infrared detector pixel arrays  

NASA Astrophysics Data System (ADS)

Infrared (IR) detectors are well established as a vital sensor technology for military, defense and commercial applications. Due to the expense and effort required to fabricate pixel arrays, it is imperative to develop numerical simulation models to perform predictive device simulations which assess device characteristics and design considerations. Towards this end, we have developed a robust three-dimensional (3D) numerical simulation model for IR detector pixel arrays. We used the finite-difference time-domain technique to compute the optical characteristics including the reflectance and the carrier generation rate in the device. Subsequently, we employ the finite element method to solve the drift-diffusion equations to compute the electrical characteristics including the I(V) characteristics, quantum efficiency, crosstalk and modulation transfer function. We use our 3D numerical model to study a new class of detector based on the nBn-architecture. This detector is a unipolar unity-gain barrier device consisting of a narrow-gap absorber layer, a wide-gap barrier layer, and a narrow-gap collector layer. We use our model to study the underlying physics of these devices and to explain the anomalously long lateral collection lengths for photocarriers measured experimentally. Next, we investigate the crosstalk in HgCdTe photovoltaic pixel arrays employing a photon-trapping (PT) structure realized with a periodic array of pillars intended to provide broadband operation. The PT region drastically reduces the crosstalk; making the use of the PT structures not only useful to obtain broadband operation, but also desirable for reducing crosstalk, especially in small pitch detector arrays. Then, the power and flexibility of the nBn architecture is coupled with a PT structure to engineer spectrally filtering detectors. Last, we developed a technique to reduce the cost of large-format, high performance HgCdTe detectors by nondestructively screen-testing detector arrays prior to their final hybridization onto expensive silicon read-out integrated circuit (ROIC) chips. The approach is to temporarily hybridize each candidate HgCdTe detector array to a standard reusable ROIC for complete screen testing. We tested the technique by temporarily hybridizing LPE grown HgCdTe test chips to fan-out boards and characterizing their performance.

Schuster, Jonathan

260

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

PubMed Central

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 among multiple MPPC and to diffuse and direct scintillation light can reduce the nonlinearity of the detector response within the limited dynamic range of a typical MPPC. As a result, the proposed PET detector module has the potential to be refined for use in high-resolution PET insert applications. PMID:20393236

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

2010-01-01

261

Germanium blocked-impurity-band detector arrays - Unpassivated devices with bulk substrates  

NASA Technical Reports Server (NTRS)

We have fabricated and characterized six-element monolithic arrays of Ge:Ga blocked-impurity-band detectors, with threshold wavelength 220 microns, peak quantum efficiency 14 percent, detective quantum efficiency 9 percent, dark current 300 e(-)/s, and response uniformity better than 4 percent. The devices are described very well by the standard model of blocked-impurity-band detectors and appear to satisfy many of the requirements of low-background astronomical instruments.

Watson, Dan M.; Guptill, Matthew T.; Huffman, James E.; Krabach, Timothy N.; Raines, S. N.; Satyapal, Shobita

1993-01-01

262

Energy spectrum of UHECRs measured by newly constructed fluorescence detectors in Telescope Array experiment  

NASA Astrophysics Data System (ADS)

Telescope Array (TA) experiment is the largest hybrid detector to observe ultra-high energy cosmic rays (UHECRs) in the northern hemisphere. In the TA experiment, we newly designed and constructed 24 fluorescence detectors (FDs) located at two stations. We report the energy spectrum of UHECRs with energies above 1017.5 eV from analyzing data collected by the new FDs during the first 3.7 years in monocular mode.

Fujii, Toshihiro

2013-06-01

263

Operational performance characteristics of the WISH detector array on the ISIS spallation neutron source  

NASA Astrophysics Data System (ADS)

The performance of the position sensitive neutron detector array of the WISH diffractometer is discussed. WISH (Wide angle In a Single Histogram) is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source, and is used mainly for magnetic studies of materials. WISH is instrumented with an array of 10 detector panels, covering an angular range of 320o, orientated in two semi-cylindrical annuli around a central sample position at a radius of 2.2m. In total the 10 detector panels are composed of 1520 3He based position sensitive detector tubes. Each tube has an active length of one metre, a diameter of 8mm and is filled with 3He at 15 bar. The specification for the WISH detectors included a neutron detection efficiency of 50% at a neutron wavelength of 1Å with good gamma rejection. A position resolution better than 8 mm FWHM along the length of the tubes was also required which has been met experimentally. Results obtained from the detector arrays showing pulse height and positional information both prior to and post installation are shown. The first 5 of the 10 detector panels have been operational since 2009, and comparable diffraction data from powder and single crystal samples taken from the remaining 5 panels (installation completed in 2013) shows that we have a detector array with a highly stable performance which is easily assembled and maintained. Finally some real user data is shown, highlighting the excellent quality of data attainable with this instrument.

Duxbury, D.; Khalyavin, D.; Manuel, P.; Raspino, D.; Rhodes, N.; Schooneveld, E.; Spill, E.

2014-12-01

264

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

NASA Technical Reports Server (NTRS)

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.

Kasle, David B. (inventor)

1995-01-01

265

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

NASA Technical Reports Server (NTRS)

The techniques and procedures for producing very-large-format pulse-counting array detector systems for use in forthcoming high-energy astrophysics facilities were defined, and the structures and performance characteristics of high-sensitivity photocathodes for use at soft X-ray wavelengths between 100 and 1 A were determined. The progress made to date in each of these areas are described and the tasks that will be undertaken when the program is continued are summarized.

Timothy, J. G.

1983-01-01

266

Characterization and simulation of linear scintillator arrays for low-energy x-ray detection  

NASA Astrophysics Data System (ADS)

Current x-ray imaging in many industrial and medical applications uses different scintillator materials coupled to photodiode arrays. Knowledge of the light distribution and photoelectron signal allows for the improvement of the imaging properties of such devices. We have measured and simulated the pixel scintillation light distribution collected by the photodiode arrays for four commercial scintillator arrays made of cesium iodide, cadmium tungstate and gadolinium oxysulfide with pitches of 0.8 mm and 1.6 mm. We used a collimated low-energy x-ray beam to study the collected signal in each array element and the effective fill factors determined from the photodiode geometry, backing material and radiation transport in the scintillator. A proper description of the optical parameters of these detectors provides excellent agreement of the experimental results with Monte Carlo simulations performed with MANTIS.

Franco, L.; Gómez, F.; Badano, A.

2008-11-01

267

Microwave Characteristics of Microwave Kinetic Inductance Detectors Using Rewound Spiral Resonators Array  

NASA Astrophysics Data System (ADS)

We investigated microwave characteristics of microwave kinetic inductance detectors (MKIDs) using rewound spiral resonators called as spiral-MKIDs. To realize 25-array spiral-MKIDs, frequency characteristics of 25 resonators with different resonant frequencies should be equal. We proposed spiral-MKIDs with expanded and contracted symmetric spiral resonator. We conducted simulations for 25 arrays and obtained maximum return losses of over 12 dB and unloaded quality factors of over 230,000 for frequencies between 3.2 and 3.4 GHz. This symmetric resonator may be useful for realization of large array MKIDs.

Hayashi, K.; Saito, A.; Sawada, T.; Ogawa, Y.; Nakajima, K.; Yamada, H.; Ariyoshi, S.; Ohshima, S.

268

Responsivity of silicon photodiodes from 0.5 to 1.1 micron at 77 K  

NASA Technical Reports Server (NTRS)

The responsivities of Si, Ge, and InSb photodiodes at 77 K are measured and compared. The results are used to determine the wavelength at which a change should occur in the detector materials used in the focal plan of the Mars Observer Visual and IR Mapping Spectrometer (VIMS). Quantitative responsivity data for Si photodiodes in the band from 0.5 to 1.1 were needed for the VIMS system analysis. The results show that the Si array for the focal plane should have two different antireflection coatings. It is found that the Si and InSb materials have equivalent quantum efficiencies at about 0.9 microns. Because of unknown signal chain complications that could be caused by a multiplexer accessing two different capacitances, the focal plane was designed with a change from Si to InSb at 1 micron.

Staller, C.; Niblack, C.; Smith, D.

1988-01-01

269

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

PubMed

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. PMID:24434681

Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

2014-02-01

270

Silicon Wafer-Scale Substrate for Microshutters and Detector Arrays  

NASA Technical Reports Server (NTRS)

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 (approximately equal to 3x3cm) without any crack propagation; implementation of IR transmission blocking techniques; and compatibility with indium bump bonding. Although designed for the microshutter arrays for the NIRSpec instrument on the James Webb Space Telescope, these substrates can be linked to microshutter applications in the photomask generation and stepper equipment used to make ICs and microelectromechanical system (MEMS) devices.

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

2009-01-01

271

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

NASA Technical Reports Server (NTRS)

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.

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

272

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

NASA Technical Reports Server (NTRS)

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.

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

273

X-ray source considerations in operation of digital detector arrays  

SciTech Connect

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.

Jensen, Terrence; Wendt, Scott [Iowa State University, Center for NDE, 1915 Scholl Road, Ames, IA 50011 (United States)

2014-02-18

274

Slot spiral detector array for broadband THz imaging1  

Microsoft Academic Search

In this work, we propose a broadband FPA pixel in form of a printed slot spiral antenna with an operation bandwidth of 500-900GHz. Moreover, the antenna impedance is carefully designed to match to that of the detector diode to exploit the maximum responsivity achievable. This broadband, high-sensitivity FPA will significantly speed-up the image acquisition times and allow THz imaging tools

Georgios C. Trichopoulos; Kubilay Sertel; John L. Volakis

2010-01-01

275

Multicolor Focal Plane Array Detector Technology: A Review  

Microsoft Academic Search

A major concern today is to accurately measure CO2, O3, H2O, and CH4 in the atmosphere for the prediction of climate and weather. These measurements are critical for understanding the Earth's atmosphere, atmospheric chemistry, and systemic forces driving climactic changes. For these measurements, detectors with high quantum efficiency and near background limited performance detectivity over a wide wavelength range are

M. Nurul Abedin; Tamer F. Refaat; Joseph Zawodny; Steve P. Sandford; Upendra N. Singh; Sumith Bandra; Sarath D. Gunapala; Ishwara Bhat; Norman P. Barnes

2003-01-01

276

Polycrystalline CVD diamond pixel array detector for nuclear particles monitoring  

NASA Astrophysics Data System (ADS)

We report the 90Sr beta response of a polycrystalline diamond pixel detector fabricated using metal-less graphitic ohmic contacts. Laser induced graphitization was used to realize multiple squared conductive contacts with 1mm × 1mm area, 0.2 mm apart, on one detector side while on the other side, for biasing, a 9mm × 9mm large graphite contact was realized. A proximity board was used to wire bonding nine pixels at a time and evaluate the charge collection homogeneity among the 36 detector pixels. Different configurations of biasing were experimented to test the charge collection and noise performance: connecting the pixel at the ground potential of the charge amplifier led to best results and minimum noise pedestal. The expected exponential trend typical of beta particles has been observed. Reversing the bias polarity the pulse height distribution (PHD) does not changes and signal saturation of any pixel was observed around ±200V (0.4 V/?m). Reasonable pixels response uniformity has been evidenced even if smaller pitch 50÷100 ?m structures need to be tested.

Pacilli, M.; Allegrini, P.; Girolami, M.; Conte, G.; Spiriti, E.; Ralchenko, V. G.; Komlenok, M. S.; Khomic, A. A.; Konov, V. I.

2013-02-01

277

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

NASA Technical Reports Server (NTRS)

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.

Domingo, George

1997-01-01

278

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

SciTech Connect

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.

Tim Roney; Robert Seifert; Bob Pink; Mike Smith

2011-09-01

279

Inexpensive THz Focal Plane Array Imaging Using Miniature Neon Indicator Lamps as Detectors  

Microsoft Academic Search

Development of focal plane arrays (FPAs) for mm wavelength and THz radiation is presented in this paper. The FPA is based upon inexpensive neon indicator lamp Glow Discharge Detectors (GDDs) that serve as pixels in the FPA. It was shown in previous investigations that inexpensive neon indicator lamp GDDs are quite sensitive to mm wavelength and THz radiation. The diameters

Daniel Rozban; Assaf Levanon; Hezi Joseph; Avihai Akram; Amir Abramovich; Natan S. Kopeika; Yitzhak Yitzhaky; Alexander Belenky; Orly Yadid-Pecht

2011-01-01

280

Multiplexed Readout of MMC Detector Arrays Using Non-hysteretic rf-SQUIDs  

NASA Astrophysics Data System (ADS)

Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to X-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQUID multiplexer that employs non-hysteretic rf-SQUIDs to create a frequency shift of high resonators that is in accordance with the detector signal and that can be monitored by using standard microwave measurement techniques. In this paper we discuss the design of a recently developed and fabricated 64 pixel detector array with integrated microwave SQUID multiplexer that was produced to test the suitability of this readout technique. The characterization of dc-SQUIDs with virtually identical washer design compared to the rf-SQUIDs of the SQUID multiplexer revealed that the crucial SQUID parameters such as the critical current of the Josephson junctions or the washer inductance are close to the design values and anticipates a successful operation of the SQUID multiplexer.

Kempf, S.; Wegner, M.; Gastaldo, L.; Fleischmann, A.; Enss, C.

2014-08-01

281

High-performance liquid chromatographic determination of acetyl-11-keto-alpha-boswellic acid, a novel pentacyclic triterpenoid, in plasma using a fluorinated stationary phase and photodiode array detection: application in pharmacokinetic studies.  

PubMed

A rapid, sensitive and selective HPLC separation with photodiode array detection was developed for the analysis of the novel pentacyclic triterpenoid acetyl-11-keto-alpha-boswellic acid. Complete baseline separation of acetyl-11-keto-alpha-boswellic acid from the corresponding isomer acetyl-11-keto-beta-boswellic acid was achieved on a fluorinated stationary phase. The standard curve was linear from 0.98 nmol/l to 196 nmol/l acetyl-11-keto-alpha-boswellic acid. The compound was isolated from chick embryonic plasma using extraction on diatomaceous earth with an overall average extraction yield of 82%. This method was applied in a kinetic study on the chick chorioallantoic membrane model (CAM) and showed unequivocal separation between acetyl-11-keto-alpha-boswellic acid and acetyl-11-keto-beta-boswellic acid unachievable so far. PMID:16266833

Büchele, Berthold; Zugmaier, Waltraud; Genze, Felicitas; Simmet, Thomas

2005-12-27

282

Development of Yangbajing Air shower Core detector array for a new EAS hybrid Experiment  

E-print Network

Aiming at the observation of cosmic-ray chemical composition at the "knee" energy region, we have been developinga new type air-shower core detector (YAC, Yangbajing Air shower Core detector array) to be set up at Yangbajing (90.522$^\\circ$ E, 30.102$^\\circ$ N, 4300 m above sea level, atmospheric depth: 606 g/m$^2$) in Tibet, China. YAC works together with the Tibet air-shower array (Tibet-III) and an underground water cherenkov muon detector array (MD) as a hybrid experiment. Each YAC detector unit consists of lead plates of 3.5 cm thick and a scintillation counter which detects the burst size induced by high energy particles in the air-shower cores. The burst size can be measured from 1 MIP (Minimum Ionization Particle) to $10^{6}$ MIPs. The first phase of this experiment, named "YAC-I", consists of 16 YAC detectors each having the size 40 cm $\\times$ 50 cm and distributing in a grid with an effective area of 10 m$^{2}$. YAC-I is used to check hadronic interaction models. The second phase of the experiment,...

Liu, Jinsheng; Chen, Ding; Zhang, Ying; Zhai, Liuming; Chen, Xu; Hu, Xiaobin; Lin, Yuhui; Zhang, Xueyao; Feng, Cunfeng; Jia, Huanyu; Zhou, Xunxiu; DanZengLuoBu,; Chen, Tianlu; Li, Haijin; Liu, Maoyuan; Yuan, Aifang

2015-01-01

283

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

284

Ultrathin NbN film superconducting single-photon detector array  

NASA Astrophysics Data System (ADS)

We report on the fabrication process of the 2 × 2 superconducting single-photon detector (SSPD) array. The SSPD array is made from ultrathin NbN film and is operated at liquid helium temperatures. Each detector is a nanowire-based structure patterned by electron beam lithography process. The advances in fabrication technology allowed us to produce highly uniform strips and preserve superconducting properties of the unpatterned film. SSPD exhibit up to 30% quantum efficiency in near infrared and up to 1% at 5-?m wavelength. Due to 120 MHz counting rate and 18 ps jitter, the time-domain multiplexing read-out is proposed for large scale SSPD arrays. Single-pixel SSPD has already found a practical application in non-invasive testing of semiconductor very-large scale integrated circuits. The SSPD significantly outperformed traditional single-photon counting avalanche diodes.

Smirnov, K.; Korneev, A.; Minaeva, O.; Divochiy, A.; Tarkhov, M.; Ryabchun, S.; Seleznev, V.; Kaurova, N.; Voronov, B.; Gol'tsman, G.; Polonsky, S.

2007-04-01

285

112-Pixel Arrays of High-Efficiency STJ X-Ray Detectors  

NASA Astrophysics Data System (ADS)

We are developing the next generation of high-resolution high-speed X-ray detectors based on superconducting tunnel junctions (STJs). They consist of 112-pixel arrays of 208 m 208 m Ta-Al--Al-Ta tunnel junctions whose Ta absorber increases the detection efficiency compared to earlier Nb-based STJs. To read out these medium size detector arrays we have also developed a compact and scalable 32-channel preamplifier with an input voltage noise 1 nV/Hz and a dc voltage bias for stable STJ operation between Fiske mode resonances. The pixels have a uniform response across the array, an energy resolution between 7.5 and 9.5 eV FWHM at 525 eV, and can be operated at several 1,000 counts/s per pixel.

Friedrich, S.; Harris, J.; Warburton, W. K.; Carpenter, M. H.; Hall, J. A.; Cantor, R.

2014-08-01

286

2K X 2K HgCdTe detector arrays for VISTA and other applications  

NASA Astrophysics Data System (ADS)

The demand for large-format near infrared arrays has grown for both ground-based and space-based applications. These arrays are required for maintaining high resolution over very large fields of view for survey work. We describe results of the development of a new 2048 × 2048 HgCdTe/CdZnTe array with 20-micron pixels that responds with high quantum efficiency over the wavelength range 0.85 to 2.5 microns. With a single-layer anti-reflection coating, the responsive quantum efficiency is greater than 70% from 0.9 micron to 2.4 microns. Dark current is typically less than 4 e-/sec at 80 K. The modular package for this array, dubbed the VIRGO array, allows 3-side butting to form larger mosaic arrays of 4K × 2nK format. The VIRGO ROIC utilizes a PMOS Source Follower per Detector input circuit with a well capacity of about 2 × 105 electrons and with a read noise of less than 20 e- rms with off-chip Correlated Double Sampling. Other features of the VIRGO array include 4 or 16 outputs (programmable), and a frame rate of up to 1.5 Hz in 16-output mode. Power dissipation is about 7 mW at a 1 Hz frame rate. Reset modes include both global reset and reset by row (ripple mode). Reference pixels are built-in to the output data stream. The first major application of the VIRGO array will be for VISTA, the United Kingdom"s Visible and Infrared Survey Telescope for Astronomy. The VISTA focal plane array will operate near 80 K. The cutoff wavelength of the HgCdTe detector can be adjusted for other applications such as SNAP, the Supernova/Acceleration Probe, which requires a shorter detector cutoff wavelength of about 1.7 microns. For applications which require both visible and near infrared response, the detector CdZnTe substrate can be removed after hybridization, allowing the thinned detector to respond to visible wavelengths as short as 0.4 microns.

Love, Peter J.; Hoffman, Alan W.; Ando, Ken J.; Corrales, Elizabeth; Ritchie, William D.; Therrien, Neil J.; Rosbeck, Joseph P.; Holcombe, Roger S.; Gulbransen, David J.

2004-09-01

287

Recent progress with multi-anode microchannel array detector systems. [for use in instruments on telescopes  

NASA Technical Reports Server (NTRS)

The construction and modes of operation of Multi-Anode Microchannel Arrays (MAMA's) are briefly reviewed. The MAMA detectors, which are a family of photoelectric, photon-counting array detectors being developed specifically for use in instruments on ground-based and space-borne telescopes, combine the high sensitivity and photometric stability of a conventional channel electron multiplier with a high-resolution imaging capability. The MAMA detectors feature low applied potential (less than 3 kV), high gain (greater than 10 to the 6th electrons/pulse), an absolute event timing accuracy of 100 ns or better, a very long count lifetime (greater than 2.5 x 10 to the 11th counts/sq mm), and a power consumption of less than 30 W for a complete system

Timothy, J. G.

1982-01-01

288

Measurement of the UHECR Energy Spectrum by the Telescope Array Fluorescence Detectors  

NASA Astrophysics Data System (ADS)

Ultra-high-energy cosmic rays (UHECRs), subatomic charged particles of extraterrestrial origin and with kinetic energies near or exceeding 10^18 eV, are very rare. The Telescope Array (TA) experiment in western Utah is the northern hemisphere's largest UHECR detector, and consists of three atmospheric fluorescence detectors (FDs) and a ground array of 507 scintillator detectors. In stand-alone ``monocular'' operation, the FDs can observe the widest range in primary UHECR energies. One FD employs refurbished hardware from the High-Resolution Fly's Eye experiment; the remaining two FDs were designed for TA and employ new hardware and analysis. We will present the UHECR energy spectrum measured by the FDs in monocular mode using data collected during the first four years of operation.

Stroman, Thomas; Bergman, Douglas

2013-04-01

289

A PARALLEL ANALOG-DIGITAL PIN PHOTODIODE PROCESSOR CHIP FOR IMAGE PRE-PROCESSING WITH OPTICAL CHIP-TO-CHIP INTERCONNECTS  

Microsoft Academic Search

A smart detector chip consisting of an array of smart pixel processing elements (PE) realised in 0.6 µm CMOS technology is presented. The area for one PE is only 250×250 µm² in which a pin photodiode, analogue\\/digital conversion and programmable digital logic are integrated. Simulations results show a data rate up to 625 Mbit\\/s for one PE, resulting in a

Lutz Hoppe; Andreas Loos; Michael Förtsch; Dietmar Fey; Horst Zimmermann

290

Vertical Isolation for Photodiodes in CMOS Imagers  

NASA Technical Reports Server (NTRS)

In a proposed improvement in complementary metal oxide/semi conduct - or (CMOS) image detectors, two additional implants in each pixel would effect vertical isolation between the metal oxide/semiconductor field-effect transistors (MOSFETs) and the photodiode of the pixel. This improvement is expected to enable separate optimization of the designs of the photodiode and the MOSFETs so as to optimize their performances independently of each other. The purpose to be served by enabling this separate optimization is to eliminate or vastly reduce diffusion cross-talk, thereby increasing sensitivity, effective spatial resolution, and color fidelity while reducing noise.

Pain, Bedabrata

2008-01-01

291

High-resolution ultrasonic imaging using an etalon detector array  

PubMed Central

A photoacoustic imaging system was built and tested to demonstrate the feasibility of high-resolution low-noise ultrasonic imaging based on parallel detection using polymer etalons. Its capability of detecting ultrasound at different elements simultaneously in the optical end was verified by imaging three 49 ?m beads. An average noise-equivalent pressure of 3.6 kPa over 50 MHz for 50 ?m diameter detection elements in a two-dimensional array with a diameter of 1.35 mm and a detection bandwidth of 75 MHz at –3 dB was measured. These results demonstrate the potential of polymer etalons for high-frame-rate high-resolution three-dimensional photoacoustic and ultrasound pulse-echo imaging. PMID:19529842

Huang, Sheng-Wen; Hou, Yang; Ashkenazi, Shai; O’Donnell, Matthew

2008-01-01

292

The role of localized junction leakage in the temperature-dependent laser-beam-induced current spectra for HgCdTe infrared focal plane array photodiodes  

SciTech Connect

We have performed the study on the dependence of laser beam induced current (LBIC) spectra on the temperature for the vacancy-doped molecular beam epitaxy grown Hg{sub 1?x}Cd{sub x}Te (x?=?0.31) photodiodes by both experiment and numerical simulations. It is found that the measured LBIC signal has different distributions for different temperature extents. The LBIC profile tends to be more asymmetric with increasing temperature below 170?K. But the LBIC profile becomes more symmetric with increasing temperature above 170?K. Based on a localized leakage model, it is indicated that the localized junction leakage can lead to asymmetric LBIC signal, in good agreement with the experimental data. The reason is that the trap-assisted tunneling current is the dominant leakage current at the cryogenic temperature below 170?K while the diffusion current component becomes dominant above the temperature of 170?K. The results are helpful for us to better clarify the mechanism of the dependence of LBIC spectra on temperature for the applications of HgCdTe infrared photodiodes.

Feng, A. L.; Li, G., E-mail: liguang1971@ahu.edu.cn, E-mail: xschen@mail.sitp.ac.cn; He, G.; Sun, Z. Q. [School of Physics and Materials Science and Anhui Key Laboratory of Information Materials and Devices, Anhui University, Hefei 230601 (China); Hu, W. D.; Chen, X. S., E-mail: liguang1971@ahu.edu.cn, E-mail: xschen@mail.sitp.ac.cn; Yin, F.; Zhang, B.; Lu, W. [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

2013-11-07

293

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

SciTech Connect

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 meet this challenge, we have examined two strategies: (1) use of subspace detectors, a multi-dimensional extension of correlators, which allow representation and detection of signals exhibiting some degree of variation; and (2) autonomous calibration of many subspace and correlation detectors in an adaptive detection framework, subject to analyst review. Because correlation detectors are relatively new to seismology, a significant amount of research on how to tune these detectors has been needed to address later calibration efforts that will arise as they are adopted for operational use. We have approached these challenges by carrying out a number of case studies, encompassing various monitoring scenarios such as earthquake aftershock sequences and swarms, recurring mining explosions, other types of explosions, and rockbursts. We have studied several different geographical regions (the European Arctic, Central Asia, and the western United States). We have drawn on available Ground Truth data in assessing the results of the various processing schemes. In all cases, we have benefited from the high-quality seismic arrays or networks available in these regions, and we have thus been able to evaluate the performance of array-based correlation processing under a variety of conditions. The main results of the project are summarized as follows: (1) Array-based waveform correlation has been demonstrated to lower significantly detection thresholds in comparison with standard single-channel waveform correlation. (2) Frequency-wavenumber analysis of the correlation traces on a small-aperture array provides an effective method for screening out a certain category of false alarms, and can therefore be used to improve detector sensitivity by lowering the threshold for automatic array detection. (3) We have developed and tested a framework for autonomous correlation detection. The framework comprises a set of conventional (STA/LTA) detectors on a collection of array beams, augmented by correlation and subspace detectors. The detectors are applied in parallel. (4) We have expe

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

2009-04-16

294

The performance of a prototype array of water Cherenkov detectors for the LHAASO project  

NASA Astrophysics Data System (ADS)

A large high-altitude air-shower observatory (LHAASO) is to be built at Shangri-La, Yunnan Province, China. This observatory is intended to conduct sub-TeV gamma astronomy, and as an important component of the LHAASO project, a water Cherenkov detector array (WCDA) is proposed. To investigate engineering issues and fully understand the water Cherenkov technique for detecting air showers, a prototype array at 1% scale of the LHAASO-WCDA has been built at Yang-Ba-Jing, Tibet, China. This paper introduces the prototype array setup and studies its performance by counting rate of each photomultiplier tube (PMT), trigger rates at different PMT multiplicities, and responses to air showers. Finally, the reconstructed shower directions and angular resolutions of the detected showers for the prototype array are given.

An, Q.; Bai, Y. X.; Bi, X. J.; Cao, Z.; Chang, J. F.; Chen, G.; Chen, M. J.; Chen, S. M.; Chen, S. Z.; Chen, T. L.; Chen, X.; Chen, Y. T.; Cui, S. W.; Dai, B. Z.; Du, Q.; Danzengluobu; Feng, C. F.; Feng, S. H.; Gao, B.; Gao, S. Q.; Ge, M. M.; Gu, M. H.; Hao, X. J.; He, H. H.; Hou, C.; Hu, H. B.; Hu, X. B.; Huang, J.; Huang, W. P.; Jia, H. Y.; Jiang, K.; Liu, J.; Liu, J. L.; Liu, J. S.; Liu, S. B.; Liu, Y.; Liu, Y. N.; Li, Q. J.; Li, C.; Li, F.; Li, H. C.; Li, X. R.; Lu, H.; Lv, H. K.; Mao, Y. J.; Ma, L. L.; Ma, X. H.; Shao, J.; Shao, M.; Sheng, X. D.; Sun, G. X.; Sun, Z. B.; Tang, Z. B.; Wu, C. Y.; Wu, H. R.; Wu, Q.; Xiao, G.; Xu, Y.; Yang, Q. Y.; Yang, R.; Yao, Z. G.; You, X. H.; Yuan, A. F.; Zhang, B. K.; Zhang, H. M.; Zhang, S. R.; Zhang, S. S.; Zhang, X. Y.; Zhang, Y.; Zhang, L.; Zhai, L. M.; Zhao, J.; Zhao, L.; Zhao, Z. G.; Zha, M.; Zhou, B.; Zhu, F. R.; Zhu, K. J.; Zhuang, J.; Zuo, X.

2013-10-01

295

The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy.  

PubMed

Single plane illumination microscopy based fluorescence correlation spectroscopy (SPIM-FCS) is a new method for imaging FCS in 3D samples, providing diffusion coefficients, transport, flow velocities and concentrations in an imaging mode. SPIM-FCS records correlation functions over a whole plane in a sample, which requires array detectors for recording the fluorescence signal. Several types of image sensors are suitable for FCS. They differ in properties such as effective area per pixel, quantum efficiency, noise level and read-out speed. Here we compare the performance of several low light array detectors based on three different technologies: (1) Single-photon avalanche diode (SPAD) arrays, (2) passive-pixel electron multiplying charge coupled device (EMCCD) and (3) active-pixel scientific-grade complementary metal oxide semiconductor cameras (sCMOS). We discuss the influence of the detector characteristics on the effective FCS observation volume, and demonstrate that light sheet based SPIM-FCS provides absolute diffusion coefficients. This is verified by parallel measurements with confocal FCS, single particle tracking (SPT), and the determination of concentration gradients in space and time. While EMCCD cameras have a temporal resolution in the millisecond range, sCMOS cameras and SPAD arrays can extend the time resolution of SPIM-FCS down to 10 ?s or lower. PMID:23571955

Singh, Anand Pratap; Krieger, Jan Wolfgang; Buchholz, Jan; Charbon, Edoardo; Langowski, Jörg; Wohland, Thorsten

2013-04-01

296

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

297

MEGHNAD - A multi element detector array for heavy ion collision studies  

NASA Astrophysics Data System (ADS)

In the coming decade, the expanding field of experimental nuclear physics in our country is going to see a quantum leap in research and developmental activities with new accelerator facilities like the variable energy cyclotron with ECR heavy ion source, the upcoming K-500 superconducting cyclotron, both at VECC, Calcutta, and the superconducting linac boosters at both the Pelletron Accelerator Facilities at TIFR, Mumbai and NSC, New Delhi. When heavy ion beam available from such machines fall on a target and undergo collision, very rich and often pristine fields of research open up. In order to carry on such activities, we have taken up a project to build a multi element gamma, heavy ion and neutron array of detectors (MEGHNAD) to detect and study the properties of a wide variety of particles like neutrons, protons, light mass clusters, massive ejected fragments, and gamma rays with good solid angle coverage and efficiency. Design of the detector array, performance of the prototype detector and brief outline of the research programme to be undertaken with the detector array will be discussed.

Saha, Satyajit

2001-07-01

298

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

NASA Astrophysics Data System (ADS)

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 that is proportional to the square root of the CRB on the angular source separation, or equivalently to the lower bound on the MSAE.

Liu, Zhi

2007-08-01

299

Multiplexed readout demonstration of a TES-based detector array in a resistance locked loop  

E-print Network

TES-based bolometer and microcalorimeter arrays with thousands of pixels are under development for several space-based and ground-based applications. A linear detector response and low levels of cross talk facilitate the calibration of the instruments. In an effort to improve the properties of TES-based detectors, fixing the TES resistance in a resistance-locked loop (RLL) under optical loading has recently been proposed. Earlier theoretical work on this mode of operation has shown that the detector speed, linearity and dynamic range should improve with respect to voltage biased operation. This paper presents an experimental demonstration of multiplexed readout in this mode of operation in a TES-based detector array with noise equivalent power values (NEP) of $3.5\\cdot 10^{-19} $W/$\\sqrt{\\mathrm{Hz}}$. The measured noise and dynamic properties of the detector in the RLL will be compared with the earlier modelling work. Furthermore, the practical implementation routes for future FDM systems for the readout of ...

van der Kuur, Jan; Kiviranta, Mikko; Akamatsu, Hiroki; Khosropanah, Pourya; Hartog, Roland den; Suzuki, Toyoaki; Jackson, Brian

2015-01-01

300

High-resolution spectroscopy with the multi-anode microchannel array detector systems  

NASA Technical Reports Server (NTRS)

The results of a series of high-resolution spectroscopic observations undertaken with a linear (1 x 1024)-pixel visible-light Multi-Anode Microchannel Array (MAMA) detector on the Coudespectrograph of the 2.2-meter telescope at the Mauna Kea Observatory and on the vacuum spectrograph of the McMath Solar telescope at the Kitt Peak National Observatory are described. In addition, the two-dimensional MAMA detector systems with (16 x 1024)-pixel, (24 x 1024)-pixel, and (256 x 1024)-pixel formats which are now being readied for use in a series of ground-based, balloon, and sounding-rocket observing programs are briefly described.

Timothy, J. G.; Joseph, C. L.; Wolf, S. C.

1982-01-01

301

Speckle spectroscopy; an application for the multi-anode microchannel array detector system  

NASA Technical Reports Server (NTRS)

Plans to combine the High Angular Resolution Imager/Spectrometer on the 4-meter Mayall telescope at the Kitt Peak National Observatory and the (256 x 1024)-pixel Multi-Anode Microchannel Array detector system to produce a unique instrument for speckle spectroscopy are described. The pulse-counting detector system will provide distortion-free imaging and will time tag each spatially-resolved photon event with an accuracy of 100 ns. The Imager/Spectrometer will provide a spatial resolution of 0.07 arcsec orthogonal to the plane of dispersion and 0.18 arcsec in the plane of dispersion.

Butcher, H. R.; Joseph, C. L.; Timothy, J. G.

1982-01-01

302

Analysis of the x-ray refraction using an array-structured detector  

SciTech Connect

A crystal-less method for analyzing the phase shifts of an x-ray beam passed through a sample is here presented. An array-structured detector is used both to record and analyze the refracted and scattered radiation. Experimental studies of simple phase objects confirmed that images show features similar or equivalent to the ones produced using an analyzer crystal with comparable signal-to-noise ratio values. Using a detector for analyzing the refraction presents evident advantages in terms of optical stability. In addition, with a single acquisition, several refraction angles can be simultaneously analyzed permitting a better exploitation of the dose delivered to the sample.

Coan, Paola; Bravin, Alberto [European Synchrotron Radiation Facility, 38043 Grenoble (France)

2007-04-30

303

Photo sensor array technology development  

NASA Technical Reports Server (NTRS)

The development of an improved capability photo sensor array imager for use in a Viking '75 type facsimile camera is presented. This imager consists of silicon photodiodes and lead sulfide detectors to cover a spectral range from 0.4 to 2.7 microns. An optical design specifying filter configurations and convergence angles is described. Three electronics design approaches: AC-chopped light, DC-dual detector, and DC-single detector, are investigated. Experimental and calculated results are compared whenever possible using breadboard testing and tolerance analysis techniques. Results show that any design used must be forgiving of the relative instability of lead sulfide detectors. A final design using lead sulfide detectors and associated electronics is implemented by fabrication of a hybrid prototype device. Test results of this device show a good agreement with calculated values.

Rossman, M. W.; Young, V. F.; Beall, J. R.

1977-01-01

304

DALI2: A NaI(Tl) detector array for measurements of $?$ rays from fast nuclei  

E-print Network

A NaI(Tl) detector array called DALI2 (Detector Array for Low Intensity radiation 2) has been constructed for in-beam $\\gamma$-ray spectroscopy experiments with fast radioactive isotope (RI) beams. It consists typically of 186 NaI(Tl) scintillators covering polar angles from $\\sim$15$^{\\circ}$ to $\\sim$160$^{\\circ}$ with an average angular resolution of 6$^{\\circ}$ 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 $\\gamma$ rays emitted from fast-moving nuclei (velocities of $v/c \\simeq 0.6$). 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.

S. Takeuchi; T. Motobayashi; Y. Togano; M. Matsushita; N. Aoi; K. Demichi; H. Hasegawa; H. Murakami

2014-06-24

305

DALI2: A NaI(Tl) detector array for measurements of ? rays from fast nuclei  

NASA Astrophysics Data System (ADS)

A NaI(Tl) detector array called DALI2 (Detector Array for Low Intensity radiation 2) has been constructed for in-beam ?-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 ? 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.

Takeuchi, S.; Motobayashi, T.; Togano, Y.; Matsushita, M.; Aoi, N.; Demichi, K.; Hasegawa, H.; Murakami, H.

2014-11-01

306

Pixel array detector for time-resolved x-ray scattering  

Microsoft Academic Search

This paper describes the development of a large-area hybrid pixel detector designed for time-resolved synchrotron x-ray scattering experiments where limited frames, with a high framing rate, is required. The final design parameters call for a 1024Ã1O24 pixel array device with 150-micron pixels that is 100% quantum efficient for x-rays with energy up to 20 keV, with a framing rate in

Brian G. Rodricks; Sandor L. Barna; Sol M. Gruner; John A. Shepherd; Mark W. Tate; Robert L. Wixted

1996-01-01

307

Pixel array detector for time-resolved x-ray scattering (invited)  

Microsoft Academic Search

This paper describes the development of a large area hybrid pixel detector designed for time-resolved synchrotron x-ray scattering experiments in which limited frames, with a high framing rate, are required. The final design parameters call for a 1024×1024 pixel array device with 150-micron pixels that is 100% quantum efficient for x-rays with energy up to 20 keV, with a framing

Brian G. Rodricks; Sandor L. Barna; Sol M. Gruner; John A. Shepherd; Mark W. Tate; Robert L. Wixted

1996-01-01

308

Detector arrays for the James Webb Space Telescope near-infrared spectrograph  

Microsoft Academic Search

The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 mum cutoff (lambdaco =5 mum) 2048×2048 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 ~ 37 K. In this article, we provide a brief introduction to NIRSpec,

Bernard J. Rauscher; David Alexander; Clifford K. Brambora; Rebecca Derro; Chuck Engler; Ori Fox; Matthew B. Garrison; Greg Henegar; Robert J. Hill; Thomas Johnson; Don J. Lindler; Sridhar S. Manthripragada; Cheryl Marshall; Brent Mott; Thomas M. Parr; Wayne D. Roher; Kamdin B. Shakoorzadeh; Miles Smith; Augustyn Waczynski; Yiting Wen; Donna Wilson; Wei Xia-Serafino; Craig Cabelli; Edward Cheng; James Garnett; Markus Loose; Majid Zandian; Joseph Zino; Timothy Ellis; Bryan Howe; Mirium Jurado; Ginn Lee; John Nieznanski; Peter Wallis; James York; Michael W. Regan; Georgio Bagnasco; Torsten Böker; Guido De Marchi; Pierre Ferruit; Peter Jakobsen; Paolo Strada

2007-01-01

309

Signal encoding method for a time-of-flight PET detector using a silicon photomultiplier array  

NASA Astrophysics Data System (ADS)

The silicon photomultiplier (SiPM) is a promising photosensor for magnetic resonance (MR) compatible time-of-flight (TOF) positron emission tomography (PET) scanners. The compact size of the SiPM allows direct one-to-one coupling between the scintillation crystal and the photosensor, yielding better timing and energy resolutions than the light sharing methods that have to be used in photomultiplier tube (PMT) PET systems. However, the one-to-one coupling scheme requires a huge volume of readout and processing electronics if no electric signal multiplexing or encoding scheme is properly applied. In this paper, we develop an electric signal encoding scheme for SiPM array based TOF PET detector blocks with the aim of reducing the complexity and volume of the signal readout and processing electronics. In an M×N SiPM array, the output signal of each channel in the SiPM array is divided into two signal lines. These output lines are then tied together in row and column lines. The row and column signals are used to measure the energy and timing information (or vice versa) of each incident gamma-ray event, respectively. Each SiPM channel was directly coupled to a 3×3×20 mm3 LGSO crystal. The reference detector, which was used to measure timing, consisted of an R9800 PMT and a 4×4×10 mm3 LYSO crystal and had a single time resolution of ~200 ps (FWHM). Leading edge discriminators were used to determine coincident events. Dedicated front-end electronics were developed, and the timing and energy resolutions of SiPM arrays with different array sizes (4×4, 8×8, and 12×12) were compared. Breakdown voltage of each SiPM channel was measured using energy spectra within various bias voltages. Coincidence events were measured using a 22Na point source. The average coincidence time resolution of 4×4, 8×8, and 12×12 SiPM arrays were 316 ps, 320 ps, and 335 ps (FWHM), respectively. The energy resolution of 4×4, 8×8, and 12×12 SiPM arrays were 11.8%, 12.5%, and 12.8% (FWHM), respectively. Because of length differences between each SiPM channel and summed signal output on printed a circuit board, propagation delay of ~111 ps was observed. A signal encoding method for a TOF PET block detector using SiPMs has been developed to reduce the complexity and volume of the signal readout and processing electronics required. The proposed method showed promising results, which were measured for various SiPM array sizes.

Kwon, Sun Il; Lee, Jae Sung

2014-10-01

310

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

SciTech Connect

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.

Dawson, J. V. [Laboratoire Astroparticule et Cosmologie, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris (France); Goessling, C.; Koettig, T.; Muenstermann, D.; Rajek, S.; Schulz, O. [Lehrstuhl fuer Experimentelle Physik IV, Technische Universitaet Dortmund, Otto-Hahn Str. 4, D-44227 Dortmund (Germany); Janutta, B.; Zuber, K. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, D-01069 Dresden (Germany); Junker, M. [Laboratori Nazionali del Gran Sasso, Assergi (Italy); Reeve, C. [University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom); Wilson, J. R. [University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)

2009-08-15

311

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

PubMed Central

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

Tom?ík, Peter

2013-01-01

312

A large area plastic scintillator detector array for fast neutron measurements  

NASA Astrophysics Data System (ADS)

A large area plastic scintillator detector array ( ˜1×1 m2) has been set up for fast neutron spectroscopy at the BARC-TIFR Pelletron laboratory, Mumbai. The energy, time and position response has been measured for electrons using radioactive sources and for monoenergetic neutrons using the 7Li (p,n1)7Be*(0.429 MeV) reaction at proton energies between 6.3 and 19 MeV. A Monte Carlo simulation of the energy dependent efficiency of the array for neutron detection is in agreement with the 7Li (p,n1) measurements. The array has been used to measure the neutron spectrum, in the energy range of 4-12 MeV, in the reaction C12+Nb93 at E(C12)=40 MeV. This is in reasonable agreement with a statistical model calculation.

Rout, P. C.; Chakrabarty, D. R.; Datar, V. M.; Kumar, Suresh; Mirgule, E. T.; Mitra, A.; Nanal, V.; Kujur, R.

2009-01-01

313

Development of Passively Cooled Long Wave Infrared Detector Arrays for NEOCam  

NASA Astrophysics Data System (ADS)

The Near Earth Object Camera (NEOCam) is a proposed space mission designed to discover and characterize most of the potentially hazardous asteroids that orbit near the Earth. NEOCam consists of an infrared telescope and a passively cooled wide-field camera operating at thermal infrared wavelengths. NASA has funded technology development for NEOCam, including the development of long wavelength infrared detector arrays that will have excellent performance at NEOCam’s zodiacal emission-limited background. Teledyne Imaging Sensors has developed and delivered for test at the University of Rochester the first set of approximately 10 micron cutoff, 1024 x 1024 HgCdTe detector arrays in accord with NEOCam requirements. The first measurements of these arrays show the development to be extremely promising: noise, dark current, quantum efficiency and well depth goals have been met by this technology at focal plane temperatures of 40K, readily attainable with passive cooling. The next set of arrays to be developed will address changes suggested by the first set of deliverables.

McMurtry, Craig W.; Lee, D.; Beletic, J.; Chen, C.; Demers, R.; Dorn, M.; Edwall, D.; Bacon Fazar, C.; Forrest, W. J.; Liu, F.; Mainzer, A. K.; Pipher, J.; Yulius, A.

2013-01-01

314

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

SciTech Connect

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.

Liu, Paul Z. Y.; Suchowerska, Natalka; Abolfathi, Peter; McKenzie, David R. [School of Physics, University of Sydney, New South Wales 2006, Australia and Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050 (Australia); School of Physics, University of Sydney, New South Wales 2006 (Australia)

2012-04-15

315

STARS\\/LiBerACE: Segmented silicon and high-purity germanium detector arrays for low-energy nuclear reaction and structure studies  

Microsoft Academic Search

The Silicon Telescope Array for Reaction Studies (STARS) consists of large-area annular double-sided silicon detectors for charged-particle identification. The Livermore Berkeley Array for Collaborative Experiments (LiBerACE) is an array of six Compton-suppressed high-purity germanium Clover detectors for efficient detection of ?-rays. These detector arrays are versatile tools for studies of neutron-induced reaction cross-sections, fission, light neutron-rich nuclei, and other low-energy

S. R. Lesher; L. Phair; L. A. Bernstein; D. L. Bleuel; J. T. Burke; J. A. Church; P. Fallon; J. Gibelin; N. D. Scielzo; M. Wiedeking

2010-01-01

316

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

PubMed

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 ?m(2) (Model CCD201-20, e2v Technologies, Inc.), bonded to a fiber optic plate (FOP), and optically coupled to a 350 ?m 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. PMID:22822419

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

2012-01-01

317

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

NASA Astrophysics Data System (ADS)

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 ?m2 (Model CCD201-20, e2v Technologies, Inc.), bonded to a fiber optic plate (FOP), and optically coupled to a 350 ?m 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.

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

2012-03-01

318

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

SciTech Connect

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.

Verma, V. B., E-mail: verma@nist.gov; Horansky, R.; Lita, A. E.; Mirin, R. P.; Nam, S. W. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States); Marsili, F.; Stern, J. A.; Shaw, M. D. [Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, California 91109 (United States)

2014-02-03

319

Double junction photodiode for X-ray CMOS sensor IC  

NASA Astrophysics Data System (ADS)

A CMOS compatible P+/Nwell/Psub double junction photodiode pixel was proposed, which can efficiently detect fluorescence from CsI(Tl) scintillation in an X-ray sensor. Photoelectric and spectral responses of P+/Nwell, Nwell/Psub and P+/Nwell/Psub photodiodes were analyzed and modeled. Simulation results show P+/Nwell/Psub photodiode has larger photocurrent than P+/Nwell photodiode and Nwell/Psub photodiode, and its spectral response is more in accordance with CsI(Tl) fluorescence spectrum. Improved P+/Nwell/Psub photodiode detecting CsI(Tl) fluorescence was designed in CSMC 0.5 ?m CMOS process, CTIA (capacitive transimpedance amplifier) architecture was used to readout photocurrent signal. CMOS X-ray sensor IC prototype contains 8 × 8 pixel array and pixel pitch is 100 × 100 ?m2. Testing results show the dark current of the improved P+/Nwell/Psub photodiode (6.5 pA) is less than that of P+/Nwell and P+/Nwell/Psub photodiodes (13 pA and 11 pA respectively). The sensitivity of P+/Nwell/Psub photodiode is about 20 pA/lux under white LED. The spectrum response of P+/Nwell/Psub photodiode ranges from 400 nm to 800 nm with a peak at 532 nm, which is in accordance with the fluorescence spectrum of CsI(Tl) in an indirect X-ray sensor. Preliminary testing results show the sensitivity of X-ray sensor IC under Cu target X-ray is about 0.21 V·m2/W or 5097e-/pixel @ 8.05 keV considering the pixel size, integration time and average energy of X-ray photons.

Chaoqun, Xu; Ying, Sun; Yan, Han; Dazhong, Zhu

2014-07-01

320

Hybrid UV Imager Containing Face-Up AlGaN/GaN Photodiodes  

NASA Technical Reports Server (NTRS)

A proposed hybrid ultraviolet (UV) image sensor would comprise a planar membrane array of face-up AlGaN/GaN photodiodes integrated with a complementary metal oxide/semiconductor (CMOS) readout-circuit chip. Each pixel in the hybrid image sensor would contain a UV photodiode on the AlGaN/GaN membrane, metal oxide/semiconductor field-effect transistor (MOSFET) readout circuitry on the CMOS chip underneath the photodiode, and a metal via connection between the photodiode and the readout circuitry (see figure). The proposed sensor design would offer all the advantages of comparable prior CMOS active-pixel sensors and AlGaN UV detectors while overcoming some of the limitations of prior (AlGaN/sapphire)/CMOS hybrid image sensors that have been designed and fabricated according to the methodology of flip-chip integration. AlGaN is a nearly ideal UV-detector material because its bandgap is wide and adjustable and it offers the potential to attain extremely low dark current. Integration of AlGaN with CMOS is necessary because at present there are no practical means of realizing readout circuitry in the AlGaN/GaN material system, whereas the means of realizing readout circuitry in CMOS are well established. In one variant of the flip-chip approach to integration, an AlGaN chip on a sapphire substrate is inverted (flipped) and then bump-bonded to a CMOS readout circuit chip; this variant results in poor quantum efficiency. In another variant of the flip-chip approach, an AlGaN chip on a crystalline AlN substrate would be bonded to a CMOS readout circuit chip; this variant is expected to result in narrow spectral response, which would be undesirable in many applications. Two other major disadvantages of flip-chip integration are large pixel size (a consequence of the need to devote sufficient area to each bump bond) and severe restriction on the photodetector structure. The membrane array of AlGaN/GaN photodiodes and the CMOS readout circuit for the proposed image sensor would be fabricated separately.

Zheng, Xinyu; Pain, Bedabrata

2005-01-01

321

Research on bi-material MEMS detector arrays for THz imaging  

NASA Astrophysics Data System (ADS)

Terahertz (THz) technology has huge potential in detection of concealed objects as well as in medical imaging for non-invasive diagnostics. Recently thanks to improvement of THz sources and detectors, the THz imaging technology has become the hotspot. This paper presents a real-time imaging system for THz radiation from BWO source. The key component of the system is the IR-FPA which is a bi-material MEMS detector array optimized for infrared wave lengths. In order to get a better THz image, the paper presents a modified FPA for THz region. Two main methods were explored to improve the detector performance in the THz region. The first way identified was the use of novel optical readout system based on SPR. The second detector improvement approach involved the change of the micro-cantilever structure that the cantilever of each pixel can shift in vertical direction. A model of one pixel was set up to optimize the structure. Computer simulations results show that both approaches are effective. The manufacturing of the proposed detector are also discussed. The technological investigation shows that it is feasible to employ sacrificial layer technique related to MEMS (Micro-Electro-Mechanical Systems) technology.l.+

Duan, Guo-teng; Su, Bo; Zhao, Ya-qin; Wang, Xiao-yan; Sun, Hui-juan; Zhang, Cun-lin; Zhao, Wei-rui

2011-08-01

322

Calibration of a detector array through beam profile reconstruction with error-locking.  

PubMed

An iterative method is proposed to calibrate radiation sensitivities of an arbitrary two-dimensional (2D) array of detectors. The array is irradiated with a wide open- field beam at the central position, as well as at laterally and longitudinal shifted positions; the 2D beam profile of the wide field is reconstructed iteratively from the ratios of shifted images to the central image. The propagation errors due to output variation and inaccurate array positioning are estimated and removed from the reconstructed beam profile by an error-locking scheme with narrow open-field irradiations. The beam profile is interpolated when necessary and then compared to raw detector responses to determine sensitivities. Two additional methods were implemented for comparison: 1) the commercial iterative calibration method for MapCHECK2 with translation and rotation operations; 2) a labor-intensive noniterative method without the issue of error propagation. A MapCHECK2 2D detector array was used to validate the proposed method with the 6 MV photon beam from a Varian iX linear accelerator. All calibration methods were repeated three times. A total of 5, 9, and 29 irradiations were required to implement the commercial method, the proposed method and the noniterative method respec- tively. Moreover, a 5 mm positioning error was intentionally introduced into the calibration procedures of the commercial and the proposed method to test their robustness. Under the normal operation condition of the linear accelerator and with careful alignment of the MapCHECK2, the deviations of the calibrated sensitivities of the proposed method and commercial method with respect to the noniterative method were 0.30% ± 0.29% and 0.92% ± 0.63% respectively; when the 5 mm positioning error was presented, these two methods resulted in deviations of 0.40% ± 0.36% and 3.58% ± 1.94%, respectively. A patient study suggested that, due to this 5 mm positioning error, the mean DTA (dose to agreement) passing rate by the commercial method was 2.7% lower than that by the noniterative method, whereas the proposed method led to a comparable passing rate. It is evident from this study that the proposed iterative method leads to within 1% mean calibration results to established methods. It requires much fewer number of measurements than noniterative method and is more robust against the positioning error than the commercial iterative method. The method also eliminates the need of rotation operations and, therefore, is applicable to inline detector arrays without rotation function, such as electronic portal imager device (EPID).  PMID:25493504

Wang, Song; Li, Zhiqiu; Chao, K S Clifford; Chang, Jenghwa

2014-01-01

323

Array detector for high energy laser based on diffuse transmission sampling  

NASA Astrophysics Data System (ADS)

In order to improve the ability and accuracy of measuring the temporal-spatial distribution of the intensity of a large-size, high-energy laser beam, a novel array detecting method based on diffuse transmission sampling is proposed. The measurement principle and the design of the sampling and attenuating unit are presented. High-temperature-resistant diffuse transmission material is used to sample and attenuate a high energy laser beam. Pure copper, whose surface is first sand-blasted and then gold-plated, is applied to scatter the incident high-energy laser beam. The formula for the attenuation ratio was derived in detail. We developed two large-aperture array detectors with spatial resolution of 5 mm, spatial duty ratio of 20%, and useable angle range of ±30° without varying the responsivity, the non-uniformity in the laser profile measurement is below 1%, and the repeatability error in the laser power measurement is approximately 1%. The maximal energy density that the array detector can endure is more than 10 kJ/cm2.

Pang, Miao; Rong, Jian; Zhou, Shan; Wu, Juan; Fan, Guobin; Zhang, Wei; Hu, Xiaoyang

2014-01-01

324

Array detector for high energy laser based on diffuse transmission sampling.  

PubMed

In order to improve the ability and accuracy of measuring the temporal-spatial distribution of the intensity of a large-size, high-energy laser beam, a novel array detecting method based on diffuse transmission sampling is proposed. The measurement principle and the design of the sampling and attenuating unit are presented. High-temperature-resistant diffuse transmission material is used to sample and attenuate a high energy laser beam. Pure copper, whose surface is first sand-blasted and then gold-plated, is applied to scatter the incident high-energy laser beam. The formula for the attenuation ratio was derived in detail. We developed two large-aperture array detectors with spatial resolution of 5 mm, spatial duty ratio of 20%, and useable angle range of ±30° without varying the responsivity, the non-uniformity in the laser profile measurement is below 1%, and the repeatability error in the laser power measurement is approximately 1%. The maximal energy density that the array detector can endure is more than 10 kJ/cm(2). PMID:24517743

Pang, Miao; Rong, Jian; Zhou, Shan; Wu, Juan; Fan, Guobin; Zhang, Wei; Hu, Xiaoyang

2014-01-01

325

Array detector for high energy laser based on diffuse transmission sampling  

SciTech Connect

In order to improve the ability and accuracy of measuring the temporal–spatial distribution of the intensity of a large-size, high-energy laser beam, a novel array detecting method based on diffuse transmission sampling is proposed. The measurement principle and the design of the sampling and attenuating unit are presented. High-temperature-resistant diffuse transmission material is used to sample and attenuate a high energy laser beam. Pure copper, whose surface is first sand-blasted and then gold-plated, is applied to scatter the incident high-energy laser beam. The formula for the attenuation ratio was derived in detail. We developed two large-aperture array detectors with spatial resolution of 5 mm, spatial duty ratio of 20%, and useable angle range of ±30° without varying the responsivity, the non-uniformity in the laser profile measurement is below 1%, and the repeatability error in the laser power measurement is approximately 1%. The maximal energy density that the array detector can endure is more than 10 kJ/cm{sup 2}.

Pang, Miao [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China) [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, 621900 China (China); Key Laboratory of High Energy Laser, CAEP, Mianyang 621900 (China); Rong, Jian [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhou, Shan; Wu, Juan; Zhang, Wei; Hu, Xiaoyang [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, 621900 China (China)] [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, 621900 China (China); Fan, Guobin [Key Laboratory of High Energy Laser, CAEP, Mianyang 621900 (China)] [Key Laboratory of High Energy Laser, CAEP, Mianyang 621900 (China)

2014-01-15

326

Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging  

PubMed Central

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-dispersive detector modules, are shown. PMID:19920884

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

2009-01-01

327

Development of a fast pixel array detector for use in microsecond time- resolved x-ray diffraction  

Microsoft Academic Search

A large-area pixel x-ray detector is being developed to collect eight successive frames of wide dy- namic 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

S. L. Barna; J. A. Shepherd; R. L. Wixted; M. W. Tate; B. Rodricks; S. M. Gruner

328

Development of a fast pixel array detector for use in microsecond time-resolved x-ray diffraction  

Microsoft Academic Search

A large-area pixel x-ray detector is being developed to collect eight successive frames of wide dynamic 2D images at 200kHz rates. Such a detector, to 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

Sandor L. Barna; John A. Shepherd; Robert L. Wixted; Mark W. Tate; Brian G. Rodricks; Sol M. Gruner

1995-01-01

329

Feasibility study of a ?-ray detector based on square PSPMT array for breast cancer imaging  

NASA Astrophysics Data System (ADS)

Although gamma cameras have emerged in the 1960s, their spatial resolution is still not sufficient to detect small tracer concentration abnormalities. Examinations like mammo-scintigraphy requires high spatial resolution and then the possibility to position the detector as close to the explored organ as possible. Diagnostic accuracy in nuclear medicine imaging has seen a notable advancement with the emergence of the new position-sensitive photomultiplier tube (PSPMT). This component allows to develop a compact gamma detector which fulfils these requirements. This study investigates the feasibility and the characteristics of a medium field of view high spatial resolution gamma ray detector based on R8520 PSPMT array coupled to a pixelated NaI(Tl) crystal array. As first results, a photocathode uniformity variation of 1-3 was observed on the whole field of view. Energy resolution obtained is better than 10% FWHM at 140 keV in PSPMT centers. Concerning spatial linearity, it depends on the uniformity of the PSPMT used. Consequently, it will be necessary to develop linearity and energy correction methods.

Tamda, N.; Bakkali, A.; Boulahdour, H.; Parmentier, M.; Pousse, A.; Kastler, B.; Chavanelle, J.

2006-02-01

330

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

NASA Astrophysics Data System (ADS)

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 ?m band. The IBC devices are also suitable for other low-background applications. The Si:As IBC detectors have a pixel dimension of 25 ?m and respond to infrared radiation between 5 and 28 ?m, covering an important Mid-IR region beyond the 1 - 5 ?m 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 ?m. The previous generation's largest, most sensitive infrared (IR) detectors at these wavelengths were the 256 × 256 / 30 ?m 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. Reset modes include both global reset and reset by row (ripple mode). Reference pixels are built-in to the output data stream. The 1K × 1K IBC is packaged in a robust modular package that consists of a multilayer motherboard, SiC pedestal, and cable assembly with 51-pin MDM connector. All materials of construction were chosen to match the thermal expansion coefficient of Silicon to provide excellent module thermal cycle reliability for cycling between room temperature and 7 K.

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

331

Soft x-ray array system with variable filters for the DIII-D tokamak  

NASA Astrophysics Data System (ADS)

Recent upgrades to the soft x-ray (SXR) array system on the DIII-D tokamak are described. The system consists of two 32-channel arrays at one toroidal location and three toroidally distributed 12-channel arrays. The 32-channel arrays have been completely rebuilt to allow the switching of SXR filters without breaking vacuum. The 12-channel arrays have had upgrades performed to detectors, view slits, and data acquisition. Absolute extreme ultraviolet (AXUV) photodiodes are used as detectors in all arrays, allowing detection of photons ranging in energy from 2 eV to 10 keV. In the fixed-filter arrays, 127 ?m Be filters are used. In the variable-filter arrays, filter wheels are used to switch between five different possible pinhole/filter combinations.

Hollmann, E. M.; Chousal, L.; Fisher, R. K.; Hernandez, R.; Jackson, G. L.; Lanctot, M. J.; Pidcoe, S. V.; Shankara, J.; Taussig, D. A.

2011-11-01

332

Robust method for investigating nitrogen metabolism of 15N labeled amino acids using AccQ•Tag ultra performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry: application to a parasitic plant-plant interaction.  

PubMed

An AccQ•Tag ultra performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry (AccQ•Tag-UPLC-PDA-ESI-MS) method is presented here for the fast, robust, and sensitive quantification of (15)N isotopologue enrichment of amino acids in biological samples, as for example in the special biotic interaction between the cultivated specie Brassica napus (rapeseed) and the parasitic weed Phelipanche ramosa (broomrape). This method was developed and validated using amino acid standard solutions containing (15)N amino acid isotopologues and/or biological unlabeled extracts. Apparatus optimization, limits of detection and quantification, quantification reproducibility, and calculation method of (15)N isotopologue enrichment are presented. Using this method, we could demonstrate that young parasite tubercles assimilate inorganic nitrogen as (15)N-ammonium when supplied directly through batch incubation but not when supplied by translocation from host root phloem, contrary to (15)N2-glutamine. (15)N2-glutamine mobility from host roots to parasite tubercles followed by its low metabolism in tubercles suggests that the host-derived glutamine acts as an important nitrogen containing storage compound in the young tubercle of Phelipanche ramosa. PMID:24359440

Gaudin, Zachary; Cerveau, Delphine; Marnet, Nathalie; Bouchereau, Alain; Delavault, Philippe; Simier, Philippe; Pouvreau, Jean-Bernard

2014-01-21

333

A new detector for mass spectrometry: Direct detection of low energy ions using a multi-pixel photon counter  

NASA Astrophysics Data System (ADS)

A new type of ion detector for mass spectrometry and general detection of low energy ions is presented. The detector consists of a scintillator optically coupled to a single-photon avalanche photodiode (SPAD) array. A prototype sensor has been constructed from a LYSO (Lu1.8Y0.2SiO5(Ce)) scintillator crystal coupled to a commercial SPAD array detector. As proof of concept, the detector is used to record the time-of-flight mass spectra of butanone and carbon disulphide, and the dependence of detection sensitivity on the ion kinetic energy is characterised.

Wilman, Edward S.; Gardiner, Sara H.; Nomerotski, Andrei; Turchetta, Renato; Brouard, Mark; Vallance, Claire

2012-01-01

334

InGaAs Schottky barrier diode array detector for a real-time compact terahertz line scanner.  

PubMed

We present a terahertz (THz) broadband antenna-integrated 1 × 20 InGaAs Schottky barrier diode (SBD) array detector with an average responsivity of 98.5 V/W at a frequency of 250 GHz, which is measured without attaching external amplifiers and Si lenses, and an average noise equivalent power (NEP) of 106.6 pW/?Hz. The 3-dB bandwidth of the SBD detector is also investigated at approximately 180 GHz. For implementing an array-type SBD detector by a simple fabrication process to achieve a high yield, a structure comprising an SiN(x) layer instead of an air bridge between the anode and the cathode is designed. THz line beam imaging using a Gunn diode emitter with a center frequency of 250 GHz and a 1 × 20 SBD array detector is successfully demonstrated. PMID:24216813

Han, Sang-Pil; Ko, Hyunsung; Park, Jeong-Woo; Kim, Namje; Yoon, Young-Jong; Shin, Jun-Hwan; Kim, Dae Yong; Lee, Dong Hun; Park, Kyung Hyun

2013-11-01

335

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

USGS Publications Warehouse

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.

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

2004-01-01

336

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

SciTech Connect

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.

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

337

Intra-pixel response of the new JWST infrared detector arrays  

NASA Astrophysics Data System (ADS)

We have repeated some of our previous measurements of the intra-pixel response of the infrared detector arrays for the Fine Guidance Sensor (FGS) instrument on the James Webb Space Telescope (JWST). This set of tests was performed on a 5 micron cutoff substrate-removed HAWAII-1RG from the new batch of devices produced for JWST. The measurements were done at wavelengths from 650 nm to 1550 nm. The results from these tests indicate that there are no significant differences in the intra-pixel response between the older JWST devices and the new ones. Modeling suggests that the primary contributor to the response profile is diffusion in the bulk detector material.

Hardy, T.; Willot, Chris; Pazder, J.

2014-07-01

338

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

NASA Technical Reports Server (NTRS)

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.

Martin, Christopher; Rasmussen, Andrew

1989-01-01

339

The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment  

E-print Network

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays for energies above 1.6x10^(18) eV in its first three years of operation. The spectrum shows a dip at an energy of 5x10^(18) eV and a steepening at 5x10^(19) eV which is consistent with the expectation from the GZK cutoff. Here we use a new technique that involves generating a complete simulation of 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.

Abu-Zayyad, T; 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; 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; Lim, S I; Machida, S; Martens, K; Martineau, J; Matsuda, T; Matsuura, T; Matsuyama, T; Matthews, J N; Minamino, M; Miyata, K; Murano, Y; Myers, I; Nagasawa, K; Nagataki, S; Nakamura, T; Nam, S W; Nonaka, T; Ogio, S; Ohnishi, M; Ohoka, H; Oki, K; Oku, D; Okuda, T; 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; 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; Wood, M; Yamakawa, Y; Yamane, R; Yamaoka, H; Yamazaki, K; Yang, J; Yoneda, Y; Yoshida, S; Yoshii, H; Zhou, X; Zollinger, R R; Zundel, Z

2012-01-01

340

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

341

Digital Electronics For The Versatile Array Of Neutron Detectors At Low Energies  

SciTech Connect

A {chi}{sup 2} minimization algorithm has been developed to extract sub-sampling-time information from digitized waveforms, to be used to instrument the future Versatile Array of Neutron Detectors at Low energies. The algorithm performance has been characterized with a fast Arbitrary Function Generator, obtaining time resolution better than 1 ns for signals of amplitudes between 50 mV and 1V, with negligible walk in the whole range. The proof-of-principle measurement of the beta-delayed neutron emission from {sup 89}Br indicates a resolution of 1 ns can be achieved in realistic experimental conditions.

Madurga, M.; Paulauskas, S.; Grzywacz, R.; Padgett, S. W.; Liddick, S. N. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Bardayan, D. W. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Batchelder, J. C.; Matei, C.; Peters, W. A.; Rasco, C. [Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Blackmon, J. C. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 708034 (United States); Cizewski, J. A.; O'Malley, P. [Department of Physics and Astronomy, Rutgers University, New Brunswick, NJ 08903, US (Canada); Goans, R. E. [Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Raiola, F.; Sarazin, F. [Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States)

2011-06-01

342

In situ two-dimensional imaging quick-scanning XAFS with pixel array detector  

PubMed Central

Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2?mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10?s to 1?min per spectrum depending on the energy range. The PAD has a wide dynamic range and low noise, so the obtained spectra have a good signal-to-noise ratio. PMID:21997918

Tanida, Hajime; Yamashige, Hisao; Orikasa, Yuki; Oishi, Masatsugu; Takanashi, Yu; Fujimoto, Takahiro; Sato, Kenji; Takamatsu, Daiko; Murayama, Haruno; Arai, Hajime; Matsubara, Eiichiro; Uchimoto, Yoshiharu; Ogumi, Zempachi

2011-01-01

343

Design and development of multicolor MWIR\\/LWIR and LWIR\\/VLWIR detector arrays  

Microsoft Academic Search

Multicolor infrared (IR) focal planes are required for high-performance sensor applications. These sensors will require multicolor\\u000a focal plane arrays (FPAs) that will cover various wavelengths of interest in mid wavelength infrared\\/long wavelength infrared\\u000a (MWIR\\/LWIR) and long wavelength infrared\\/very long wavelength infrared (LWIR\\/VLWIR) bands. There has been significant progress\\u000a in HgCdTe detector technology for multicolor MWIR\\/LWIR and LWIR\\/VLWIR FPAs.1–3 Two-color IR

Ashok K. Sood; James E. Egerton; Yash R. Puri; Enrico Bellotti; Donald D’Orsogna; Latika Becker; Raymond Balcerak; Ken Freyvogel; Robert Richwine

2005-01-01

344

Far Field Monitoring of Rogue Nuclear Activity with an Array of Large Anti-neutrino Detectors  

NASA Astrophysics Data System (ADS)

The result of a study on the use of an array of large anti-neutrino detectors for the purpose of monitoring rogue nuclear activity is presented. Targeted regional monitoring of a nation bordering large bodies of water with no pre-existing legal nuclear activity may be possible at a cost of about several billion dollars, assuming several as-yet-untested schemes pan out in the next two decades. These are: (1) the enabling of a water-based detector to detect reactor anti-neutrinos by doping with GdCl3; (2) the deployment of a KamLAND-like detector in a deep-sea environment; and (3) the scaling of a Super-Kamiokande-like detector to a size of one or more megatons. The first may well prove feasible, and should be tested by phase-III Super-Kamiokande in the next few years. The second is more of a challenge, but may well be tested by the Hanohano collaboration in the coming decade. The third is perhaps the least certain, with no schedule for construction of any such device in the foreseeable future. In addition to the regional monitoring scheme, several global, untargeted monitoring schemes were considered. All schemes were found to fail benchmark sensitivity levels by a wide margin, and to cost at least several trillion dollars.

Guillian, Eugene H.

2006-12-01

345

Tiled Array of Pixelated CZT Imaging Detectors for ProtoEXIST2 and MIRAX-HXI  

E-print Network

We have assembled a tiled array (220 cm2) of fine pixel (0.6 mm) imaging CZT detectors for a balloon borne wide-field hard X-ray telescope, ProtoEXIST2. ProtoEXIST2 is a prototype experiment for a next generation hard X-ray imager MIRAX-HXI on board Lattes, a spacecraft from the Agencia Espacial Brasilieira. MIRAX will survey the 5 to 200 keV sky of Galactic bulge, adjoining southern Galactic plane and the extragalactic sky with 6' angular resolution. This survey will open a vast discovery space in timing studies of accretion neutron stars and black holes. The ProtoEXIST2 CZT detector plane consists of 64 of 5 mm thick 2 cm x 2 cm CZT crystals tiled with a minimal gap. MIRAX will consist of 4 such detector planes, each of which will be imaged with its own coded-aperture mask. We present the packaging architecture and assembly procedure of the ProtoEXIST2 detector. On 2012, Oct 10, we conducted a successful high altitude balloon experiment of the ProtoEXIST1 and 2 telescopes, which demonstrates their technolog...

Hong, Jaesub; Grindlay, Jonathan; Rodrigues, Barbara; Ellis, Jon Robert; Baker, Robert; Barthelmy, Scott; Mao, Peter; Miyasaka, Hiromasa; Apple, Jeff

2013-01-01

346

Low noise avalanche photodiodes  

Microsoft Academic Search

The maximum useful gain in avalanche photodiodes (APDs) is limited by the noise associated with the random fluctuations of the avalanche process which increase with multiplication. The conventional McIntyre theory relates this excess noise F, to the value of the mean multiplication, M and the ratio of the hole to electron ionization coefficients (? and ? respectively), k. For electron

J. P. R. David; G. J. Rees

2001-01-01

347

Silicon carbide UV photodiodes  

Microsoft Academic Search

SiC photodiodes were fabricated using 6 H single-crystal wafers. These devices have excellent UV responsivity characteristics and very low dark current even at elevated temperatures. The reproducibility is excellent and the characteristics agree with theoretical calculations for different device designs. The advantages of these diodes are that they will operate at high temperatures and are responsive between 200 and 400

D. M. Brown; E. T. Downey; M. Ghezzo; J. W. Kretchmer; R. J. Saia; Y. S. Liu; J. A. Edmond; G. Gati; J. M. Pimbley; W. E. Schneider

1993-01-01

348

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

NASA Technical Reports Server (NTRS)

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.

Lakew, Brook

2009-01-01

349

Enhanced radiation detectors using luminescent materials  

DOEpatents

A radiation detecting device comprising a radiation sensing element, and a layer of luminescent material to expand the range of wavelengths over which the sensing element can efficiently detect radiation. The luminescent material being selected to absorb radiation at selected wavelengths, causing the luminescent material to luminesce, and the luminescent radiation being detected by the sensing element. Radiation sensing elements include photodiodes (singly and in arrays), CCD arrays, IR detectors and photomultiplier tubes. Luminescent materials include polymers, oligomers, copolymers and porphyrines, Luminescent layers include thin films, thicker layers, and liquid polymers.

Vardeny, Zeev V. (Holladay, UT); Jeglinski, Stefan A. (Durham, NC); Lane, Paul A. (Sheffield, GB)

2001-01-01

350

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

NASA Astrophysics Data System (ADS)

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.

Gökçe, Muhsin C.; Kamac?o?lu, Canan; Uysal, Murat; Baykal, Yahya

2014-10-01

351

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

PubMed

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. PMID:23756497

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

2013-07-01

352

Photon-number-resolving detector with 10 bits of resolution  

SciTech Connect

A photon-number-resolving detector with single-photon resolution is described and demonstrated. It has 10 bits of resolution, does not require cryogenic cooling, and is sensitive to near ir wavelengths. This performance is achieved by flood illuminating a 32x32 element In{sub x}Ga{sub 1-x}AsP Geiger-mode avalanche photodiode array that has an integrated counter and digital readout circuit behind each pixel.

Jiang, Leaf A.; Dauler, Eric A.; Chang, Joshua T

2007-06-15

353

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

PubMed

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. PMID:23367292

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

2012-01-01

354

LAMBDA: Large Area Modular BaF2 Detector Array for the measurement of high energy gamma rays  

E-print Network

A large BaF2 detector array along with its dedicated CAMAC electronics and VME based data acquisition system has been designed, constructed and installed successfully at VECC, Kolkata for studying high energy gamma rays (E>8 MeV). The array consists of 162 detector elements. The detectors were fabricated from bare barium fluoride crystals (each measuring 35 cm in length and having cross-sectional area of 3.5 cm X 3.5 cm X 35.0 cm). The basic properties of the detectors (energy resolution, time resolution, efficiency, uniformity, fast to slow ratio etc.) were studied exhaustively. Complete GEANT3 monte carlo simulations were performed to optimize the detector design and also to generate the response function. The detector system has been used successfully to measure high energy photons from 113Sb, formed by bombarding 145 and 160 MeV 20Ne beams on a 93Nb target. The measured experimental spectra are in good agreement with those from a modified version of the statistical model code CASCADE. In this paper, we present the complete description of this detector array along with its in-beam performance.

S. Mukhopadhyay; Srijit Bhattacharya; Deepak Pandit; A. Ray; Surajit Pal; K. Banerjee; S. Kundu; T. K. Rana; S. Bhattacharya; C. Bhattacharya; A. De; S. R. Banerjee

2007-10-11

355

ZnO homojunction photodiodes based on Sb-doped p-type nanowire array and n-type film for ultraviolet detection  

SciTech Connect

ZnO p-n homojunctions based on Sb-doped p-type nanowire array and n-type film were grown by combining chemical vapor deposition (for nanowires) with molecular-beam epitaxy (for film). Indium tin oxide and Ti/Au were used as contacts to the ZnO nanowires and film, respectively. Characteristics of field-effect transistors using ZnO nanowires as channels indicate p-type conductivity of the nanowires. Electron beam induced current profiling confirmed the existence of ZnO p-n homojunction. Rectifying I-V characteristic showed a turn-on voltage of around 3 V. Very good response to ultraviolet light illumination was observed from photocurrent measurements.

Wang Guoping; Chu Sheng; Zhan Ning; Liu Jianlin [Department of Electrical Engineering, Quantum Structures Laboratory, University of California at Riverside, Riverside, California 92521 (United States); Lin Yuqing; Chernyak, Leonid [Department of Physics, University of Central Florida, Orlando, Florida 32816-2385 (United States)

2011-01-24

356

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

NASA Technical Reports Server (NTRS)

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.

1988-01-01

357

New read-out electronics concept for visual and infrared detector arrays in astronomical instrumentation  

NASA Astrophysics Data System (ADS)

With the building of scientific camera systems for astronomical purposes in mind, the Max-Planck-Institut fuer Astronomie (MPIA) has recently started developing new visual and infrared detector Read-out systems. Due to the modular design, the electronics components can be configured for a wide range of currently available IR-detectors and CCDs. The new Read-out Electronics are able to handle single or multiple detector systems with up to 144 input channels, feature high-speed data transfer and low power dissipation and additionally the system size is small and lightweight. The design is divided in four functional groups: controller board with variable Pattern Generator and fast fiber link, clock/bias board, analog to digital converter board and the PCI data receiver board which writes the incoming data into the computer memory. This design is highly versatile and allows for a wide variety of applications. The high data transfer rate, small size and low heat dissipation makes these Read-out Electronics ideal for relatively large focal plane arrays. The first instrument running with the new Read-out Electronics will be PANIC (Panoramic Near Infrared Camera) at the 2.20 m telescope on Calar Alto.

Wagner, Karl; Mall, Ulrich; Ramos, José; Klein, Ralf

2008-07-01

358

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

359

Silicon PIN diode hybrid arrays for charged particle detection: Building blocks for vertex detectors at the SSC  

SciTech Connect

Two-dimensional arrays of solid state detectors have long been used in visible and infrared systems. Hybrid arrays with separately optimized detector and readout substrates have been extensively developed for infrared sensors. The characteristics and use of these infrared readout chips with silicon PIN diode arrays produced by MICRON SEMICONDUCTOR for detecting high-energy particles are reported. Some of these arrays have been produced in formats as large as 512 /times/ 512 pixels; others have been radiation hardened to total dose levels beyond 1 Mrad. Data generation rates of 380 megasamples/second have been achieved. Analog and digital signal transmission and processing techniques have also been developed to accept and reduce these high data rates. 9 refs., 15 figs., 2 tabs.

Kramer, G.; Gaalema, S.; Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.

1989-05-01

360

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

NASA Astrophysics Data System (ADS)

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.

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

361

Photovoltaic ultraviolet detectors based on Zr(0.04)Ti(0.96)O2 solid solution nanowire arrays.  

PubMed

A Zr(0.04)Ti(0.96)O(2) solid solution nanowire (NW) array was prepared and characterized in detail. Zr doping effectively changed Zr(x)Ti(1-x)O(2)'s bandgap and led to better photoelectric properties, which indicated the possibility for deep UV detector fabrication. Based on the NW array, high-performance Schottky diode UV detector with Ag electrode was fabricated. At -3 V bias, the dark current of the detector is only 5 nA, and a high photoresponse of 5.6 A/W was achieved because of the internal gain. The ratio of photocurrent to dark current is more than three orders of magnitude. The device is promising for large-area UV detector applications. PMID:23385916

Zhang, Haifeng; Li, Hailong; Zhang, Min; Feng, Caihui; Gu, Xuehui; Xu, Yang; Zhou, Jingran; Ruan, Shengping

2013-02-01

362

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

Microsoft Academic Search

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

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

1998-01-01

363

Progress in the use of avalanche photodiodes for readout for calorimeters  

SciTech Connect

During the past year the Superconducting Super Collider Tracking Group has progressed from acquisition of its first avalanche photodiode (APD) to installation of a 96-channel array of the devices. The work was motivated by the desire to learn how to use APDs as the sensitive elements in a fiber tracking detector, moderated by the presence of limited resources and the absence of activity within groups outside the SSC Laboratory on such a project. We chose, therefore, to team up with an ongoing research effort which intended to evaluate both pre-shower and shower-maximum detectors and various means of sensing the light produced. The pre-shower detector is made of layers of scintillating fibers similar to a fiber tracker. The shower-maximum detector uses optical fibers to transmit the light from scintillating plates to the readout devices. Our contribution has been to develop the APD array for use in this test from concept to operation. Currently, the equipment is installed in Fermilab's MP beamline awaiting delivery to the final 36 APDs and exposure to the beam. 9 refs., 18 figs.

Fenker, H.; Morgan, K.; Regan, T.

1991-09-01

364

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

NASA Astrophysics Data System (ADS)

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.

Perez, E.; Salazar, H.; Villasenor, L.; et al.

365

SOLID2: An Antibody Array-Based Life-Detector Instrument in a Mars Drilling Simulation Experiment (MARTE)  

Microsoft Academic Search

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

Víctor Parro; Patricia Fernández-Calvo; José A. Rodríguez Manfredi; Mercedes Moreno-Paz; Luis A. Rivas; Miriam García-Villadangos; Rosalba Bonaccorsi; José Eduardo González-Pastor; Olga Prieto-Ballesteros; Andrew C. Schuerger; Mark Davidson; Javier Gómez-Elvira; Carol R. Stoker

2008-01-01

366

Optical fiber readout of scintillator arrays using a multi-channel PMT: a high resolution PET detector for animal imaging  

Microsoft Academic Search

The authors report the results from a new high resolution gamma ray imaging detector designed for use in a positron emission tomography (PET) system dedicated to small animal imaging. The detectors consist of an 8×8 array of 2×2×10 mm bismuth germanate (BGO) crystals coupled by 2 mm diameter double clad optical fibers to a 64 pixel multi-channel photomultiplier tube (MC-PMT).

Simon R. Cherry; Yiping Shao; Stefan Siegel; Robert W. Silverman; Erkan Mumcuoglu; Ken Meadors; Michael E. Phelps

1996-01-01

367

Investigation of atmosphere thickness on EAS events by an array of particle detectors and CORSIKA simulations  

NASA Astrophysics Data System (ADS)

Actually until the shower maximum the effect of the atmosphere is: 'an environment for extension of EAS events', but after it the 'absobtion effect of the atmosphere' will be dominant. Since the shower maximum for 100 TeV is 550 gr/cm2( 5000m a.s.l), and we are always after it (1200m a.s.l) specially for higher zenith angle events. So actually in the energy and the site we have to concentrate more on the absorbtion effect. Therefore for the investigation we logged about 400,000 EAS events by an array of particle detectors in a square 6m*6m. These cylindrical (r=35cm, h=120cm) detectors contain pure water and a face sinked PMT inside the water for detection of emitted Cerencov light from passed charged particles through the water. We calculated the local coordinates of (z,?) of each event. The z distribution of the logged events is dN=sin(z)cosn(z)dz with n=6.03. It seems that the decreasing distribution is due to the atmosphere thickness, so for better investigations of the effect we calculated the time differences between each two to six following events and we obtained the rate=(29.33+-0.14 sec)-1. With the rate and Hillass formula (Gaisser 1990) we obtained the energy threshold E_{th}=52 TeV. From 70,000 CORSIKA simulations of our experiment we obtained it 58 TeV. Then we fitted our simulated EAS events (50TeV to 5PeV) on the characteristics of our detectors and our array, and we calculated a probability distribution for different zenith angles which is in agreement with z distribution of our experiment. Also we drew the distribution of number of the secondary particles vs. z and the distribution of number of simulated events vs. secondary particles. Then we extracted the distribution of the number of simulated events vs. z. This is a good observable factor to compare with the experiment result. Our results show that a good coincidence between the simulated and observed curves. small differences in different zenith angles is from the 'efficiency of our array' which is in the investigation precess.

Khakian Ghomi, M.; Bahmanabadi, M.; Samimi, J.; et al.

368

Super resolution and optical properties of THz double row array based on inexpensive Glow Discharge Detector (GDD) pixels  

NASA Astrophysics Data System (ADS)

The properties of terahertz (THz) radiation are well known. They penetrate well most non-conducting media; there are no known biological hazards, and atmospheric attenuation and scattering is lower than visual and IR radiation. Thus THz imaging is very attractive for homeland security, biological, space, and industrial applications Recently we have found experimentally that inexpensive miniature neon indicator lamp Glow Discharge Detectors (GDD) can be used as THz detectors. Based on the GDD we designed, constructed, and experimentally tested an 8×8 GDD array. In order to improve the performance and the resolution of the THz images a larger array is required. In this work we use a special double row 2×18 moving array detector. The 2×18 GDD array enables us to employ scanning method in order to obtain 36×36 pixel THz images. Furthermore, using this double row array it will be possible to employ super resolution methods. Optical properties such as optical transfer function and measurement of point spread function are presented, as well as first results for the 2×18 GDD array.

Abramovich, A.; Kopeika, N. S.; Rozban, D.; Levanon, A.; Shilemay, Moshe; Akram, A.; Joseph, H.; Yadid-Pecht, O.; Belenky, A.

2011-11-01

369

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

NASA Astrophysics Data System (ADS)

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 within approximately one day with a relatively small staff effort. The results obtained from the first user trials are reported.

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

2014-12-01

370

H + and He + spectroscopy using silicon pin photodiodes  

NASA Astrophysics Data System (ADS)

Silicon PIN photodiodes have been used in detecting H + and He + ions from a 1 MeV accelerator. Energy resolutions (FWHM) from 2.0 keV (at 16 keV) to 4.7 keV (at 1 MeV) for H + and from 3.4 keV (at 22 keV) to 9.8 keV (at 700 keV) for He + have been measured at room temperature. Resolution measurements over this energy range using a premium PIPS detector have also been performed. A comparison between the two detectors shows that the photodiodes exhibit better energy resolution over the whole energy range for H +, and comparable resolution for He +. It is argued that the resolution of the photodiode can be further improved by manufacturing a device with thinner entrance window.

Markevich, N.; Gertner, I.; Felsteiner, J.

1988-06-01

371

Effects of 1-MeV gamma radiation on a multi-anode microchannel array detector tube  

NASA Technical Reports Server (NTRS)

A multianode microchannel array (MAMA) detector tube without a photocathode was exposed to a total dose of 1,000,000 rads of 1-MeV gamma radiation from a Co-60 source. The high-voltage characteristic of the microchannel array plate, average dark count, gain, and resolution of pulse height distribution characteristics showed no degradation after this total dose. In fact, the degassing of the microchannels induced by the high radiation flux had the effect of cleaning up the array plate and improving its characteristics.

Timothy, J. G.; Bybee, R. L.

1979-01-01

372

Optimizing the signal-to-noise ratio in the measurement of photon pairs with detector arrays  

NASA Astrophysics Data System (ADS)

To evidence multimode spatial entanglement of spontaneous down-conversion, detector arrays allow a full-field measurement, without any a priori selection of the paired photons. We show by comparing results of the recent literature that electron-multiplying CCD cameras allow, in the present state of technology, the detection of quantum correlations with the best signal-to-noise ratio (SNR), while intensified CCD cameras allow at best the identification of pairs. The SNR appears to be proportional to the square root of the number of coherence cells in each image, or Schmidt number. Then corrected estimates are derived for extended coherence cells and not-very-low and non-space-stationary photon fluxes. Finally, experimental measurements of the SNR confirm our model.

Lantz, Eric; Moreau, Paul-Antoine; Devaux, Fabrice

2014-12-01

373

Tapered LSO Arrays for Small Animal PET  

PubMed Central

By using detectors with good depth encoding accuracy (~ 2 mm), an animal PET scanner can be built with a small ring diameter and thick crystals to simultaneously obtain high spatial resolution and high sensitivity. However, there will be large wedge-shaped gaps between detector modules in such a scanner if traditional cuboid crystal arrays are used in a polygonal arrangement. The gaps can be minimized by using tapered scintillator arrays enabling the sensitivity of the scanner to be further improved. In this work, tapered lutetium oxyorthosilicate (LSO) arrays with different crystal dimensions and different combinations of inter-crystal reflector and crystal surface treatments were manufactured and their performance was evaluated. Arrays were read out from both ends by position-sensitive avalanche photodiodes (PSAPDs). In the optimal configuration, arrays consisting of 0.5 mm LSO elements could be clearly resolved and a depth of interaction resolution of 2.6 mm was obtained for a 20-mm thick array. For this tapered array, the intrinsic spatial is degraded from 0.67 mm to 0.75 mm compared to a standard cuboidal array with similar dimensions, while the increase in efficiency is 41%. Tapered scintillator arrays offer the prospect of improvements in sensitivity and sampling for small-bore scanners, without large increases in manufacturing complexity. PMID:21119228

Yang, Yongfeng; James, Sara St.; Wu, Yibao; Du, Huini; Qi, Jinyi; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Vaigneur, Keith; Cherry, Simon R.

2011-01-01

374

New insights from studies of spontaneous fission with large detector arrays  

NASA Astrophysics Data System (ADS)

The new insights into a) the rapidly varying structures of neutron-rich nuclei up to spins as high as 20 + and 19 -, b) the spontaneous fission process itself, and c) modes of cluster radioactivity that have come out of studies of spontaneous fission of 242Pu, 248Cm and 252Cf with large detector arrays are presented. The studies include ?-?-? coincidences with the second generation (14-20 Compton-suppressed Ge arrays) and new, third generation (35-45 Compton-suppressed Ge arrays, Gammasphere and Eurogam) gamma-ray detector arrays. The neutron-rich nuclei observed span the full range from superdeformed ( ?2 ? 0.4) double-magic ground states to spherical double-magic nuclei and competing shapes in between. New structure insights include the following: New regions of identical ground state bands to spins of 10 + to 16 + were discovered; one at the sudden onset of large deformation at N=60,62 in both even- and odd-A 98-101Sr, one at midshell N = 64,66 in 108,110Ru, one for N = 88-90 144,146Ba, one for N = 92-94 152,154Nd, and at high spin in 156Nd and also in excited bands in these regions. New shape coexisting structures in both even- and odd-A for A = 96-102 Sr and Zr nuclei are found. Evidence is found in both even-even and odd-A nuclei for a new region of octupole deformation around Z = 56 and N = 86-88. Rapid changes in moments of inertia are observed with changes in Z and N of two units with sudden changes in the moments of inertia associated with band crossings. The levels in many neutron-rich nuclei are observed for the first time. Earlier, plunger studies yielded lifetimes of low spin states and recently the Doppler Shift Line Shape Analysis yielded lifetimes of high spin states. For the first time, direct measurements of yields and neutron multiplicities have been made for five correlated pairs of fission fragments of Sr?Nd, Zr?Ce, Mo?Ba, Ru?Xe and Pd?Te nuclei. Neutron multiplicities from 0-10 v emission (10v for the first time) were observed in Mo?Ba correlated pairs with the 0 and 7-10 neutron-emission yields enhanced compared to gross yields for all fragments. The Mo?Ba data provide evidence for two different fission modes. By unfolding the observed Mo?Ba yields, the masses and excitation energies and mass distributions at scission were extracted. These data revealed a new mode involving the high neutron multiplicities that occurs essentially through one pair, 108Mo? 144Ba, 107Mo? 145Ba, or 106Mo? 146Ba or some combination where the 144Ba, 145Ba and/or 146Ba at scission are hyperdeformed with a long-to-short axis ratio of 3:1. The zero-neutron emission channels provide new examples of the cold rearrangements of nucleons in a new type of cluster radioactivity. The cluster radioactivity model predicted the observed enhancements of the zero-neutron channels for odd-A-odd-A nuclei as well as the observed fine structure, that is, the spin distributions of the two fragments. The measurements of intensities and ?-?-? coincidences in SF with large detector arrays open a new era in the determination of previously inaccessible properties of neutron-rich nuclei and the fission process.

Hamilton, J. H.; Ramayya, A. V.; Zhu, S. J.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.; Cole, J. D.; Rasmussen, J. O.; Stoyer, M. A.

375

Reducing the Read Noise of H2RG Detector Arrays by more Efficient use of Reference Signals  

NASA Technical Reports Server (NTRS)

We present a process for characterizing the correlation properties of the noise in large two-dimensional detector arrays, and describe an efficient process for its removal. In the case of the 2k x 2k HAWAII-2RG detectors (H2RG) detectors from Teledyne which are being used on the Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST), we find that we can reduce the read noise by thirty percent. Noise on large spatial scales is dramatically reduced. With this relatively simple process, we provide a performance improvement that is equivalent to a significant increase in telescope collecting area for high resolution spectroscopy with NIRSpec.

Rauscher, Bernard J.; Arendt, Richard G.; Fixen, D. J.; Lindler, Don; Loose, Markus; Moseley, S. H.; Wilson, D. V.

2011-01-01

376

Binary HPLC-diode array detector and HPLC-evaporative light-scattering detector fingerprints of methanol extracts from the selected sage (Salvia) species.  

PubMed

This study is focused on an important family of the sage (Salvia) species, with Salvia officinalis L. having a long-established position in European traditional medicine. Binary fingerprints (chromatographic profiles) of six different sage species were compared using HPLC coupled with two different detectors: the diode-array detector and the evaporative light-scattering detector. Advantages of using binary fingerprinting over single-detector fingerprinting are demonstrated and discussed, with selected examples. Experimental data are provided for a comparison of the chemical composition of sage samples originating from two harvesting seasons (2007 and 2008). A number of phytochemical standards (i.e., certain phenolic acids, flavonoids, and coumarin) were used that allowed identification and semiquantitative estimation of these particular compounds in the analyzed methanol extracts. PMID:21391482

Sajewicz, Mieczys?aw; Staszek, Dorota; Wojtal, ?ukasz; Kowalska, Teresa; Hajnos, Micha? ?; Waksmundzka-Hajnos, Monika

2011-01-01

377

Uniformity studies of inductively coupled plasma etching in fabrication of HgCdTe detector arrays  

NASA Astrophysics Data System (ADS)

Inductively coupled plasma (ICP) chemistry based on a mixture of CH 4, Ar, and H II was investigated for the purpose of delineating HgCdTe mesa structures and vias typically used in the fabrication of second and third generation infrared photo detector arrays. We report on ICP etching uniformity results and correlate them with plasma controlling parameters (gas flow rates, total chamber pressure, ICP power and RF power). The etching rate and surface morphology of In-doped MWIR and LWIR HgCdTe showed distinct dependences on the plasma chemistry, total pressure and RF power. Contact stylus profilometry and cross-section scanning electron microscopy (SEM) were used to characterize the anisotropy of the etched profiles obtained after various processes and a standard deviation of 0.06 ?m was obtained for etch depth on 128 x 128 format array vias. The surface morphology and the uniformity of the etched surfaces were studied by plan view SEM. Atomic force microscopy was used to make precise assessments of surface roughness.

Bommena, R.; Velicu, S.; Boieriu, P.; Lee, T. S.; Grein, C. H.; Tedjojuwono, K. K.

2007-04-01

378

Microfabricated Post-Array-Detectors (mPADs): an Approach to Isolate Mechanical Forces  

PubMed Central

In a variety of situations in living organisms, cells interact with their environment by generating traction forces. For example, muscle contractility (cardiac, skeletal and smooth muscles), ECs and permeability, stem cell differentiation might correlate with contractility (maybe…Engler). There are currently few methods by which one can measure the traction forces in a quantitative way, especially on the single-cell level; the most common method by which to study cells in vitro has been to use a polystyrene dish. However, the rigidity of the substrates makes it impossible to visualize cell traction forces. Thus, it has been difficult to quantitatively study the underlying mechanisms by which a cell generates traction forces, and how traction forces can be modulated to promote normal development or halt disease progression. Our lab has developed a technique to overcome these limitations. The method is based on a vertical array of flexible cantilevers, the stiffness and size scale of which are such that individual cells spread across many cantilevers and deflect them in the process. We can measure the deflections under a microscope and calculate the magnitude and direction of traction forces required to produce the observed deflections. We call these substrates microfabricated post-array-detectors, or mPADs. Here, we will show you how we fabricate and use the mPADs to asses modulations of cellular contractility. PMID:18989444

Desai, Ravi; Yang, Michael; Sniadecki, Nathan; Legant, Wesley; Chen, Christopher

2007-01-01

379

Final report on LDRD project : single-photon-sensitive imaging detector arrays at 1600 nm.  

SciTech Connect

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 uncertainty existed about the quantum efficiency at 1550 nm the necessary operating temperature. This project has resulted in several conclusions after fabrication and measurement of the proposed structures. We have successfully demonstrated the Ge/Si proof-of-concept in producing high analog gain in a silicon region while absorbing in a Ge region. This has included significant Ge processing infrastructure development at Sandia. However, sensitivity is limited at low temperatures due to high dark currents that we ascribe to tunneling. This leaves remaining uncertainty about whether this structure can achieve the desired performance with further development. GM detection in InGaAs/InAlAs, Ge/Si, Si and pure Ge devices fabricated at Sandia was shown to overcome gain noise challenges, which represents critical learning that will enable Sandia to respond to future single photon detection needs. However, challenges to the operation of these devices in GM remain. The InAlAs multiplication region was not found to be significantly superior to current InP regions for GM, however, improved multiplication region design of InGaAs/InP APDs has been highlighted. For Ge GM detectors it still remains unclear whether an optimal trade-off of parameters can achieve the necessary sensitivity at 1550 nm. To further examine these remaining questions, as well as other application spaces for these technologies, funding for an Intelligence Community post-doc was awarded this year.

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

380

Detection of ultra-high energy neutrino interactions in ice: comparing radio detector array designs  

NASA Astrophysics Data System (ADS)

Ultra-high energy (UHE, >10^18 eV) cosmic neutrinos are anticipated to reveal the most distant, most obscured, and highest energy particle accelerators in the Universe. An almost guaranteed flux of UHE neutrinos is predicted from the interactions of UHE cosmic rays with the cosmic microwave background, and additional contributions may arise from prompt emission at individual sources. The spectrum of UHE neutrinos is a sensitive discriminator of the cosmological evolution of UHE sources, as well as the composition of UHE cosmic rays. At the same time, UHE neutrinos will enable several tests of fundamental physics, including constraints on the neutrino-nucleon interaction cross section at center-of-momentum energies ~100 TeV, and searches for Lorentz invariance violation.Theoretical predictions and subsequent laboratory measurements of coherent radio emission from showers initiated by neutrino interactions in dielectric media (e.g., ice, sand, salt, lunar regolith) have motivated diverse experimental approaches involving "detectors" comprised of up to millions of cubic kilometers of natural materials. I will discuss simulation results comparing the expected performance of several proposed radio detector array designs with subterranean, ice shelf, and above ice configurations.

Bechtol, Keith; Vieregg, Abigail

2014-08-01

381

A Deuterated Neutron Detector Array for the Study of Nuclear Reactions with Stable and Rare Isotope Beams  

E-print Network

A Deuterated Neutron Detector Array for the Study of Nuclear Reactions with Stable and Rare Isotope Riccobono January 18, 1959 ­ March 4, 2013 #12;iii ACKNOWLEDGEMENTS To My Family ­ Sam Riccobono, Amber done for me during my undergraduate and graduate education. My favorite course during nuclear

Becchetti, Fred

382

mm wave and THz imaging using very inexpensive neon-indicator lamp detector focal-plane arrays  

Microsoft Academic Search

Development of focal plane arrays (FPA) for mm wavelength and THz radiation is presented in this paper. The FPA is based upon inexpensive neon indicator lamp Glow Discharge Detectors (GDDs) that serve as pixels in the FPA. It was shown in previous investigations that inexpensive neon indicator lamps GDDs are quite sensitive to mm wavelength and THz radiation. The diameter

D. Rozban; A. Levanon; A. Akram; A. Abramovich; N. S. Kopeika; H. Joseph; Y. Yitzthaky; A. Belenky; O. Yadid-Pecht

2011-01-01

383

Design and construction of a target chamber and associated equipments for the BARC Charged Particle Detector Array  

NASA Astrophysics Data System (ADS)

A 60 cm diameter spherical high-vacuum target-chamber with side-opening hemispherical-lids, two ancillary-chambers, beam-line-tubes, tees and other high-vacuum components, and chamber-lid handling systems have been designed, constructed and installed for the Charged Particle Detector Array in BARC-TIFR Pelletron-LINAC Facility, Mumbai. This array of several tens of Si-CsI detector modules and other ancillary-detectors will be used for investigations in fusion-fission dynamics, nuclear structure at elevated temperatures and angular momenta, exotic nuclear clusters and related fields. This paper describes the unique features of the system that aid different coincidence experiments, the chamber fabrication experience and the pump-down characteristics with a turbo molecular pump. Unlike many other target chambers in use, this chamber allows multiple overall geometrical configurations to be set to reach experimental goals. For instance, by replacing a hemispherical-lid from one side with a flat-lid, the overall configuration becomes hemispherical. This way, high geometrical efficiency can be provided to an ancillary gamma detector array by allowing it to move close to target from the flat-lid side, although with some sacrifice of geometrical efficiency for charged particles. In experiments where a further improvement of geometrical efficiency for a gamma array is desired, a third compact-cylinder configuration can also be arrived at. Thinned portion of the lids of the chamber also allow neutron coincidence measurements with charged particles and gamma rays.

John, Bency; Kumar, S. Sunil; Kumar, Manish; Jangale, R. V.; Inkar, A. L.; Kinage, Lalit

2012-11-01

384

Separation and Identification of Phenolic Acids from Some Species of the Asteraceae Family Using HPLC with a Diode Array Detector  

Microsoft Academic Search

The qualitative and quantitative analysis of phenolic acids was carried out using methods of HPLC with the diode array detector (DAD). The quantitative analysis of chosen phenolic acids was carried out using the Multicomponent Analysis method (MCA). Solid-phase extraction was applied for the purification of crude extract from aerial part of three species of fam. Asteraceae (Chrysanthemum maximum Ram.(DC), Chrysanthemum

W. Markowski; L. K. Czapi?ska; A. J. Józefczyk; K. Glowniak

1998-01-01

385

Photon counting modules using RCA silicon avalanche photodiodes  

Microsoft Academic Search

Avalanche photodiodes (APD) are excellent small area, solid state detectors for photon counting. Performance possibilities include: photon detection efficiency in excess of 50 percent; wavelength response from 400 to 1000 nm; count rate to 10 (exp 7) counts per sec; afterpulsing at negligible levels; timing resolution better than 1 ns. Unfortunately, these performance levels are not simultaneously available in a

Alexander W. Lightstone; Andrew D. MacGregor; Darlene E. MacSween; Robert J. McIntyre; Claude Trottier; Paul P. Webb

1989-01-01

386

Initial results from the Sherbrooke avalanche photodiode positron tomograph  

Microsoft Academic Search

The design features and engineering constraints of a PET system based on avalanche photodiode (APD) detectors have been described in a previous report. Here, the authors present the initial results obtained with the Sherbrooke APD-PET scanner, a very high spatial resolution device designed for dynamic imaging of small and medium-sized laboratory animals such as rats, cats, rabbits and small monkeys.

R. Lecomte; J. Cadorette; S. Rodrigue; D. Lapointe; D. Rouleau; M. Bentourkia; R. Yao; P. Msaki

1996-01-01

387

Recent developments in avalanche photodiodes for scintillating fiber applications  

NASA Astrophysics Data System (ADS)

Research is ongoing to tailor proportional mode avalanche photodiodes (APDs) for use in nuclear radiation environments and for scintillating fiber readout. We report progress on APD design modifications directed toward minimizing signals from ionizing particle interactions and also toward producing APD arrays for scintillating fiber readout. In addition, we present results for very high gain APDs fabricated using a new planar process which shows great promise for lower production costs of both APD arrays and discrete devices.

Farrell, Richard; Vanderpuye, Kofi; Vasile, Stefan; Gordon, Jeffrey S.; Gothoskar, Prakash

1998-11-01

388

Demonstration of large format mid-wavelength infrared focal plane arrays based on superlattice and BIRD detector structures  

NASA Astrophysics Data System (ADS)

We have demonstrated the use of bulk antimonide based materials and type-II antimonide based superlattices in the development of large area mid-wavelength infrared (MWIR) focal plane arrays (FPAs). Barrier infrared photodetectors (BIRDs) and superlattice-based infrared photodetectors are expected to outperform traditional III-V MWIR and LWIR imaging technologies and are expected to offer significant advantages over II-VI material based FPAs. We have used molecular beam epitaxy (MBE) technology to grow InAs/GaSb superlattice pin photodiodes and bulk InAsSb structures on GaSb substrates. The coupled quantum well superlattice device offers additional control in wavelength tuning via quantum well sizes and interface composition, while the BIRD structure allows for device fabrication without additional passivation. As a demonstration of the large area imaging capabilities of this technology, we have fabricated mid-wavelength 1024 × 1024 pixels superlattice imaging FPAs and 640 × 512 MWIR arrays based on the BIRD concept. These initial FPA have produced excellent infrared imagery.

Hill, Cory J.; Soibel, Alexander; Keo, Sam A.; Mumolo, Jason M.; Ting, David Z.; Gunapala, Sarath D.

2009-11-01

389

Gamma-ray multiplicity measurement of the spontaneous fission of 252Cf in a segmented HPGe/BGO detector array  

NASA Astrophysics Data System (ADS)

Coincident ? rays from a 252Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1 ?Ci252Cf source to cover a large solid angle for ?-ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt ? rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a ?-ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.

Bleuel, D. L.; Bernstein, L. A.; Burke, J. T.; Gibelin, J.; Heffner, M. D.; Mintz, J.; Norman, E. B.; Phair, L.; Scielzo, N. D.; Sheets, S. A.; Snyderman, N. J.; Stoyer, M. A.; Wiedeking, M.

2010-12-01

390

Large dynamic range radiation detector and methods thereof  

DOEpatents

According to one embodiment, a radiation detector comprises a scintillator and a photodiode optically coupled to the scintillator. The radiation detector also includes a bias voltage source electrically coupled to the photodiode, a first detector operatively electrically coupled to the photodiode for generating a signal indicative of a level of a charge at an output of the photodiode, and a second detector operatively electrically coupled to the bias voltage source for generating a signal indicative of an amount of current flowing through the photodiode.

Marrs, Roscoe E. (Livermore, CA); Madden, Norman W. (Sparks, NV)

2012-02-14

391

Geiger-Mode Avalanche Photodiodes in Particle Detection  

E-print Network

It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present an array of pixels of 1mmx1mm fabricated with a standard CMOS technology for characterization in a test beam.

E. Vilella; O. Alonso; J. Trenado; A. Vilà; M. Vos; L. Garrido; A. Diéguez

2012-01-27

392

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

SciTech Connect

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.

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

393

Geiger-mode Avalanche Photodiodes for High Time Resolution Astrophysics  

Microsoft Academic Search

Geiger-mode Avalanche Photodiodes (GM-APDs) are establishing themselves as potential candidates for the broad temporal range\\u000a covered in high time resolution astrophysics (HTRA). These detectors have already been employed in astronomical instrumentation\\u000a and significant results have been obtained to date. Their high time resolution and quantum efficiency make these single photon\\u000a event counting detectors ideal for observations of stochastic phenomena, and

Don Phelan; Alan P. Morrison

2008-01-01

394

Ultraviolet photodetectors and imaging arrays based on III-V nitride heterostructures  

NASA Astrophysics Data System (ADS)

The III-V nitride class of compound semiconductors has received much attention in the last decade. These materials have a wide, direct bandgap, making them a prime candidate for optoelectronic devices in the blue, green, and ultraviolet spectral regions. These materials exhibit impressive optical, electrical, and thermal properties, even though there are fundamental materials issues that are thus far unresolved. This work explores the application of III-V nitride semiconductors to optical detectors in the ultraviolet region of the electromagnetic spectrum. Metalorganic vapor phase epitaxy was used to synthesize thin film p-i-n photodiode structures on double side polished sapphire substrates; these films were characterized for optical, electrical and structural properties. The grown structures were designed to respond to a predetermined region of the UV spectrum when illuminated from the substrate side. These structures were fabricated into devices using generally accepted techniques for dry etching and p and n-contact metallizations. Test devices were characterized using tools developed by the author. These devices demonstrated as high as 80% quantum efficiency and extremely low dark currents; resulting in spectral detectivities as large as 6 * 1013 cmHz1/2W-1. Devices were designed and demonstrated for a series of detection regions ranging from 365 nm to 250 nm. Photolithography masks were designed to allow the fabrication of photodiode arrays that would hybridize to commercially available CMOS based readout integrated circuits (ROICs), used routinely for infrared photodiode imaging. Photodiode arrays were fabricated and indium bumps were deposited onto the diode contacts and the ROICs to provide electrical connection. The hybrid detector arrays were placed in leadless chip carriers, wirebonded, and connected to commercially available drive and readout circuitry. Images of UV scenes were focused onto the arrays using fused quartz lenses. These images and movies were successfully collected at frame rates up to 240 Hz using both 32 x 32 and 128 x 128 III-V nitride based UV photodiode imagers.

Brown, Jeffrey David

2000-10-01

395

LHD plasma emission measurements by means of absolute XUV photodiodes  

NASA Astrophysics Data System (ADS)

The paper describes the measurements of the LHD plasma total radiation. The 16-channel pinhole type array was based on Absolute XUV photodiodes (AXUVD) (www.ird-inc.com). The detectors have an extended range of photon energies 20 eV \\x81E10 keV, for which sensitivity is high and approximately constant (0.22-0.27 A/W). AXUV diodes are also fast, miniature, easy to use and relatively inexpensive. The plasma radiation profiles were reconstructed using modified Abel inversion procedure. Comparison of the AXUVD data with that obtained from usual metal foil bolometer was made. It shows that on LHD AXUVD cannot be directly used for total radiation power measurements instead of the metal foil bolometer. The reason is the nonlinear spectral response of AXUVD in the low energy part of spectrum (<20 eV). However, for each discharge it is possible to calculate the ratio between the AXUVD and bolometer signals and to use it for AXUVD data correction. Relatively small (<10sinusoidal oscillations of the AXUVD signal were detected during the whole steady state portion of the discharges with the average density higher than 0.5*10**19cm**-3 and He puffing. The frequency changes smoothly during the discharge in the range of 0.5 to 2 kHz.

Kostrioukov, Artem; Peterson, Byron; Sudo, Shigeru; Osakabe, Masaki; Ozaki, Tetuo; Ida, Katsumi

2001-10-01

396

The VCSEL-based array optical transmitter (ATx) development towards 120-Gbps link for collider detector: development update  

NASA Astrophysics Data System (ADS)

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.

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

397

Evaluation of GM-APD array devices for low-light-level imaging  

NASA Astrophysics Data System (ADS)

The ability to count single photons is necessary to achieve many important science objectives in the near future. This paper presents the lab-tested performance of a photon-counting array-based Geiger-mode avalanche photodiode (GMAPD) device in the context of low-light-level imaging. Testing results include dark count rate, afterpulsing probability, intra-pixel sensitivity, and photon detection efficiency, and the effects of radiation damage on detector performance. The GM-APD detector is compared to the state-of-the-art performance of other established detectors using Signal-to-noise ratio as the overall evaluation metric.

Kolb, Kimberly; Hanold, Brandon; Lee, Joong; Figer, Donald F.

2014-05-01

398

Silicon pin diode array hybrids as building blocks for a vertex detector at an asymmetric B-factory  

SciTech Connect

Silicon PIN diode hybrid arrays are proposed as the ideal building blocks for a vertex detector at an asymmetric B-factory. The two-dimensional nature of the detector segmentation allows for the maximum in confusion elimination. Fine spatial resolution, on the order of 10 {mu}m per layer, is more than adequate to resolve the displaced vertices of beauty and charm decays. A high signal-to-noise ratio allows for the thinning of the detectors, reducing multiple scattering. Time tagging within the detector permits higher background levels than could otherwise be tolerated, and on-board electronics which includes zero suppression and ghost elimination, eases downstream data handling and analysis. 8 refs., 3 figs.

Shapiro, S.L.

1990-09-01

399

The high resolution array (HiRA) for rare isotope beam experiments  

NASA Astrophysics Data System (ADS)

The High Resolution Array (HiRA) is a large solid-angle array of silicon strip-detectors that has been developed for use in a variety of nuclear structure, nuclear astrophysics and nuclear reaction experiments with short lived beta-unstable beams. It consists of 20 identical telescopes each composed of a thin (65?m) single-sided silicon strip-detector, a thick (1.5 mm) double-sided silicon strip-detector, and four CsI(Tl) crystals read out by photodiodes. The array can be easily configured to meet the detection requirements of specific experiments. To process the signals from the 1920 strips in the array, an Application Specific Integrated Circuit (ASIC) was developed. The design and performance characteristics of HiRA are described.

Wallace, M. S.; Famiano, M. A.; van Goethem, M.-J.; Rogers, A. M.; Lynch, W. G.; Clifford, J.; Delaunay, F.; Lee, J.; Labostov, S.; Mocko, M.; Morris, L.; Moroni, A.; Nett, B. E.; Oostdyk, D. J.; Krishnasamy, R.; Tsang, M. B.; de Souza, R. T.; Hudan, S.; Sobotka, L. G.; Charity, R. J.; Elson, J.; Engel, G. L.

2007-12-01

400

Calorimeter prototype based on silicon drift detectors coupled to scintillators for Compton telescopes application  

Microsoft Academic Search

The project of a new calorimeter module for Compton telescopes based on an array of silicon drift detectors (SDD) coupled to thallium activated cesium iodide (CsI(Tl)) scintillating crystals is presented. Because of their low output capacitance and the possibility to have the first amplifying stage directly integrated on chip, SDDs show better noise performances than traditional p-intrinsic-n (PIN) photodiodes. For

M. Marisaldi; C. Labanti; A. Bulgarelli; E. Celesti; G. Di Cocco; F. Gianotti; A. Mauri; E. Rossi; A. Traci; M. Trifoglio

2004-01-01

401

HDVIP HgCdTe and Silicon Detectors and FPAs for Remote Sensing Applications  

Microsoft Academic Search

Photon detectors and focal plane arrays (FPAs) are fabricated from HgCdTe and silicon in many varieties. DRS LPE-grown SWIR, MWIR and LWIR HgCdTe material fabricated in the High-Density Vertically Integrated Photodiode (HDVIP) architecture has been focused primarily on high background systems applications with great success. Remote sensing applications, however, may need to operate under both high and low background conditions.

A. D'Souzaz; M. G. Stapelbroek; E. Atkins; H. Hogue; J. Reekstin; M. Skokan; M. Kinch; P. Liao; M. Ohlson; P. Ronci; T. Teherani; H. Shih

2006-01-01

402

New numerical simulation approach to calibrate the NaI(Tl) detectors array using non-axial extended spherical sources  

NASA Astrophysics Data System (ADS)

The aim of the current study was to utilize the efficiency transfer technique (ET) to obtain the full-energy peak efficiency (FEPE) applying a new numerical simulation approach. The approach was implemented on a detection system array composed of two [NaI (Tl)] detectors. The simulation approach included a derivative of the effective solid angles subtended by an arbitrarily located source and the active volume of the detectors. The attenuation of the source matrix, the source container and the end-caps of the detector materials were considered. Resulting outcomes have been compared with those measured by the NaI(Tl) detector array comprising different volumes as (3'' × 3'' & 2'' × 2'') and resolutions (FWHM) of 7.5% and 8.5% at 662 keV respectively. 152Eu aqueous radioactive spherical sources were employed during the measurements, covering the energy range from 121.78 keV up to 1408.03 keV. A remarkable agreement was observed between the measured and the calculated efficiencies employing the new numerical approach. These conclusions were consistent for a variety of source-to-detector lateral distances, providing solid evidence for the stability of the developing method.

Badawi, M. S.; El-Khatib, A. M.; Krar, M. E.

2013-11-01

403

Shear Force at the Cell-Matrix Interface: Enhanced Analysis for Microfabricated Post Array Detectors  

PubMed Central

The interplay of mechanical forces between the extracellular environment and the cytoskeleton drives development, repair, and senescence in many tissues. Quantitative definition of these forces is a vital step in understanding cellular mechanosensing. Microfabricated post array detectors (mPADs) provide direct measurements of cell-generated forces during cell adhesion to extracellular matrix. A new approach to mPAD post labeling, volumetric imaging, and an analysis of post bending mechanics determined that cells apply shear forces and not point moments at the matrix interface. In addition, these forces could be accurately resolved from post deflections by using images of post tops and bases. Image analysis tools were then developed to increase the precision and throughput of post centroid location. These studies resulted in an improved method of force measurement with broad applicability and concise execution using a fully automated force analysis system. The new method measures cell-generated forces with less than 5%error and less than 90 seconds of computational time. Using this approach, we demonstrated direct and distinct relationships between cellular traction force and spread cell surface area for fibroblasts, endothelial cells, epithelial cells and smooth muscle cells. PMID:16708468

Lemmon, Christopher A.; Sniadecki, Nathan J.; Ruiz, Sami Alom; Tan, John L.; Romer, Lewis H.; Chen, Christopher S.

2006-01-01

404

Design and study of a coplanar grid array CdZnTe detector for improved spatial resolution.  

PubMed

Coplanar grid (CPG) CdZnTe detectors have been used as gamma-ray spectrometers for years. Comparing with pixelated CdZnTe detectors, CPG CdZnTe detectors have either no or poor spatial resolution, which directly limits its use in imaging applications. To address the issue, a 2×2 CPG array CdZnTe detector with dimensions of 7×7×5mm(3) was fabricated. Each of the CPG pairs in the detector was moderately shrunk in size and precisely designed to improve the spatial resolution while maintaining good energy resolution, considering the charge loss at the surface between the strips of each CPG pairs. Preliminary measurements were demonstrated at an energy resolution of 2.7-3.9% for the four CPG pairs using 662keV gamma rays and with a spatial resolution of 3.3mm, which is the best spatial resolution ever achieved for CPG CdZnTe detectors. The results reveal that the CPG CdZnTe detector can also be applied to imaging applications at a substantially higher spatial resolution. PMID:25305523

Ma, Yuedong; Xiao, Shali; Yang, Guoqiang; Zhang, Liuqiang

2014-12-01

405

An evaluation to design high performance pinhole array detector module for four head SPECT: a simulation study  

NASA Astrophysics Data System (ADS)

The purpose of this study is to derive optimized parameters for a detector module employing an off-the-shelf X-ray camera and a pinhole array collimator applicable for a range of different SPECT systems. Monte Carlo simulations using the Geant4 application for tomographic emission (GATE) were performed to estimate the performance of the pinhole array collimators and were compared to that of low energy high resolution (LEHR) parallel-hole collimator in a four head SPECT system. A detector module was simulated to have 48 mm by 48 mm active area along with 1mm, 1.6mm and 2 mm pinhole aperture sizes at 0.48 mm pitch on a tungsten plate. Perpendicular lead septa were employed to verify overlapping and non-overlapping projections against a proper acceptance angle without lead septa. A uniform shape cylindrical water phantom was used to evaluate the performance of the proposed four head SPECT system of the pinhole array detector module. For each head, 100 pinhole configurations were evaluated based on sensitivity and detection efficiency for 140 keV ?-rays, and compared to LEHR parallel-hole collimator. SPECT images were reconstructed based on filtered back projection (FBP) algorithm where neither scatter nor attenuation corrections were performed. A better reconstruction algorithm development for this specific system is in progress. Nevertheless, activity distribution was well visualized using the backprojection algorithm. In this study, we have evaluated several quantitative and comparative analyses for a pinhole array imaging system providing high detection efficiency and better system sensitivity over a large FOV, comparing to the conventional four head SPECT system. The proposed detector module is expected to provide improved performance in various SPECT imaging.

Rahman, Tasneem; Tahtali, Murat; Pickering, Mark R.

2014-09-01

406

James Webb Space Telescope Near-Infrared Spectrograph: dark performance of the first flight candidate detector arrays  

Microsoft Academic Search

The James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 mum cutoff (lambdaco =5 mum) 2048×2048 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 Tau ~ 37 K. This article focuses on the measured performance of the first

Bernard J. Rauscher; David Alexander; Clifford K. Brambora; Meng Chiao; Brian L. Clemons; Rebecca Derro; Charles Engler; Ori Fox; Matthew B. Garrison; Matthew A. Greenhouse; Greg Henegar; Robert J. Hill; Thomas Johnson; Rodolfo J. Lavaque; Don J. Lindler; Sridhar S. Manthripragada; Cheryl Marshall; Brent Mott; Thomas M. Parr; Wayne D. Roher; Kamdin B. Shakoorzadeh; Miles Smith; Augustyn Waczynski; Yiting Wen; Donna Wilson; Mary Ballard; Craig Cabelli; Edward Cheng; James Garnett; Elliott Koch; Markus Loose; Majid Zandian; Joseph Zino; Timothy Ellis; Bryan Howe; Miriam Jurado; Ginn Lee; John Nieznanski; Peter Wallis; James York; Michael W. Regan; Giorgio Bagnasco; Torsten Böker; Guido De Marchi; Pierre Ferruit; Peter Jakobsen; Paolo Strada

2008-01-01

407

Qualitative and quantitative analysis of anthraquinones in rhubarbs by high performance liquid chromatography with diode array detector and mass spectrometry.  

PubMed

Rhubarb is well known in traditional Chinese medicines (TCMs) mainly due to its effective purgative activity. Anthraquinones, including anthraquinone derivatives and their glycosides, are thought to be the major active components in rhubarb. To improve the quality control method of rhubarb, we studied on the extraction method, and did qualitative and quantitative analysis of widely used rhubarbs, Rheum tanguticum Maxim. ex Balf. and Rheum palmatum L., by HPLC-photodiode array detection (HPLC-DAD) and HPLC-mass spectrum (HPLC-MS) on a Waters SymmetryShield RP18 column (250 mm × 4.6 mm i.d., 5 ?m). Amount of five anthraquinones was viewed as the evaluating standard. A standardized characteristic fingerprint of rhubarb was provided. From the quantitative analysis, the rationality was demonstrated for ancestors to use these two species of rhubarb equally. Under modern extraction methods, the amount of five anthraquinones in Rheum tanguticum Maxim. ex Balf. is higher than that in Rheum palmatum L. Among various extraction methods, ultrasonication with 70% methanol for 30 min is a promising one. For HPLC analysis, mobile phase consisted of methanol and 0.1% phosphoric acid in water with a gradient program, the detection wavelength at 280nm for fingerprinting analysis and 254 nm for quantitative analysis are good choices. PMID:23870882

Wei, Shao-yin; Yao, Wen-xin; Ji, Wen-yuan; Wei, Jia-qi; Peng, Shi-qi

2013-12-01

408

Signal and Noise Properties of Position-Sensitive Avalanche Photodiodes  

PubMed Central

After many years of development, position-sensitive avalanche photodiodes (PSAPDs) are now being incorporated into a range of scintillation detector systems, including those used in high-resolution small-animal PET and PET/MR scanners. In this work, the signal, noise, signal-to-noise ratio (SNR), flood histogram and timing resolution were measured for lutetium oxyorthosilicate (LSO) scintillator arrays coupled to PSAPDs ranging in size from 10–20 mm, and the optimum bias voltage and working temperature determined. Variations in the SNR performance of PSAPDs with the same dimensions were small, but the SNR decreased significantly with increasing PSAPD size and increasing temperature. Smaller PSAPDs (10 mm and 15 mm in width) produced acceptable flood histograms at 24 °C, and cooling lower than 16 °C produced little improvement. The optimum bias voltage was about 25 V below the break down voltage. The larger 20 mm PSAPDs have lower SNR and require cooling to 0–7 °C for acceptable performance. The optimum bias voltage also is lower (35 V or more below the break down voltage depending on the temperature). Significant changes in the timing resolution were observed as the bias voltage and temperature were varied. Higher bias voltages provided better timing resolution. The best timing resolution obtained for individual crystals was 2.8 ns and 3.3 ns for the 10 mm and 15 mm PSAPDs, respectively. The results of this work provide useful guidance for selecting the bias voltage and working temperature for scintillation detectors that incorporate PSAPDs as the photodetector. PMID:21896961

Yang, Yongfeng; Wu, Yibao; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Cherry, Simon R.

2011-01-01

409

Study of Ultra-High Energy Cosmic Ray Composition Using Telescope Array's Middle Drum Detector and Surface Array in Hybrid Mode  

E-print Network

Previous measurements of the composition of Ultra-High energy Cosmic Rays (UHECRs) made by the High Resolution Fly's Eye (HiRes) and Pierre Auger Observatory (PAO) are seemingly contradictory but utilize different detection methods, as HiRes was a stereo detector and PAO is a hybrid detector. The five year Telescope Array (TA) Middle Drum hybrid composition measurement is similar in methodology to PAO, and good agreement is evident between data and a light, largely protonic composition using simulations from a variety of hadronic models for the comparison of both elongation rate and shower fluctuations. This is in good agreement with the HiRes results. This analysis is presented using two methods: data cuts using simple geometrical variables and a new pattern recognition technique.

Abbasi, R U; Abu-Zayyad, T; Allen, M; Anderson, R; Azuma, R; Barcikowski, E; Belz, J W; Bergman, D R; Blake, S A; Cady, R; Chae, M J; 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; Lim, S I; 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; Sampson, A L; 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; 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; Yoshiia, H; Zollinger, R; Zundel, Z

2014-01-01

410

Study on optimization of water Cherenkov detector array of LHAASO project for surveying VHE gamma rays sources  

E-print Network

A water Cherenkov detector array, LHAASO-WCDA, is proposed to be built at Shangri-la, Yunnan Province, China. As one of the major components of the LHAASO project, the main purpose of it is to survey the northern sky for gamma ray sources in the energy range from 100 GeV to 30 TeV. In order to design the water Cherenkov array efficiently to economize the budget, a Monte Carlo simulation is proceeded. With the help of the simulation, cost performance of different configurations of the array is obtained and compared with each other, serving as a guide for the more detailed design of the experiment in the next step.

Hui-Cai, Li; Huan-Yu, Jia; Bo, Gao; Han-Rong, Wu; Zhi-Guo, Yao; Xiao-Hao, Yuo; Bin, Zhou; Feng-Rong, Zhu

2013-01-01

411

High-gain APD array for photon detection  

NASA Astrophysics Data System (ADS)

Arrays of high speed, high gain avalanche photodiodes (APDs) have been developed for use as high sensitivity optical photon detectors. The 1 mm2 area APD pixels yield a maximum avalanche gain of 40,000 and a high signal-to-noise ratio with only moderate cooling (-22 degrees to -43 degrees C). These devices demonstrate 70% detection efficiency for 6 photon optical pulses and 35% detection efficiency for 3 photon optical pulses. The rise time is less than 2 nsec, and the fall time less than 7 nsec. Pixellating the PAD into a monolithic array will significantly reduce the cost per pixel compared to discrete devices. These devices will have great utility in various applications, ranging from high energy physics to biological instrumentation. The measured performance of these APD arrays as optical detectors will be discussed.

Farrell, Richard; Redus, Robert H.; Gordon, Jeffrey S.; Gothoskar, Prakash

1995-09-01

412

Infrared focal plane array based on MWIR\\/LWIR dual-band QWIPs: detector optimization and array properties  

Microsoft Academic Search

Quantum well infrared photodetectors (QWIPs) have gained maturity for large focal plane arrays (FPA) with excellent thermal resolution, low 1\\/f noise, low fixed-pattern noise, and high pixel operability. Due to their spectrally narrow absorption, QWIPs are particularly suitable for thermal imaging applications involving several atmospheric transmission bands or several colors within the same band. We report on our progress on

Harald Schneider; Thomas Maier; Joachim Fleissner; Martin Walther; Peter Koidl; Gunter Weimann; Wolfgang Cabanski; Marcus Finck; Peter Menger; Werner Rode; Johann Ziegler

2005-01-01

413

Arrays  

NSDL National Science Digital Library

This interactive Flash applet helps students develop the concept of equal groups as a foundation for multiplication and division. The applet displays an array of dots, some of which are covered by a card. Student use the visible number of rows and columns to determine the total number of dots. Clicking on the card reveals the full array, and a voice announces the total.

2011-01-01

414

A high-sensitivity, fast-response, rapid-recovery p-n heterojunction photodiode based on rutile TiO2 nanorod array on p-Si(1 1 1)  

NASA Astrophysics Data System (ADS)

The growth and characterization of a p-n heterojunction photodiode were studied. This photodiode was based on rutile TiO2 nanorods (NRs) grown on p-type (1 1 1)-oriented silicon substrate seeded with a TiO2 layer synthesized by radio-frequency (RF) reactive magnetron sputtering. Chemical bath deposition (CBD) was performed to grow rutile TiO2 NRs on Si substrate. The structural and optical properties of the sample were studied by X-ray diffraction (XRD) and field emission-scanning electron microscopy (FESEM) analyses. Results showed the tetragonal rutile structure of the synthesized TiO2 NRs. Optical properties were further examined by photoluminescence spectroscopy, and a high-intensity UV peak centered at around 392 nm compared with visible defect peaks centered at 527 and 707 nm was observed. Upon exposure to 395 nm light (2.3 mW/cm) at five-bias voltage, the device showed 2.9 × 102 sensitivity. In addition, the internal gain of the photodiode was 3.92, and the photoresponse peak was 106 mA/W. Furthermore, the photocurrent was 3.06 × 10-4 A. The response and the recovery times were calculated to be 10.4 and 11 ms, respectively, upon illumination to a pulse UV light (405 nm, 0.22 mW/cm2) at five-bias voltage. All of these results demonstrate that this high-quality photodiode can be a promising candidate as a low-cost UV photodetector for commercially integrated photoelectronic applications.

Selman, Abbas M.; Hassan, Z.; Husham, M.; Ahmed, Naser M.

2014-06-01

415

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

NASA Technical Reports Server (NTRS)

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.

Timothy, J. G.

1986-01-01

416

Study of a New Design of P-N Semiconductor Detector Array for Nuclear Medicine Imaging by Monte Carlo Simulation Codes  

PubMed Central

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 Tc99_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 semiconductor P-N detectors such as P-NiO:Li, N-SnO2 :F for gamma detection could be possibly applicable for design of a one dimension array configuration with suitable spatial resolution of 2.7 mm for nuclear medicine imaging. PMID:25298932

Hajizadeh-Safar, M.; Ghorbani, M.; Khoshkharam, S.; Ashrafi, Z.

2014-01-01

417

Study of a new design of p-N semiconductor detector array for nuclear medicine imaging by monte carlo simulation codes.  

PubMed

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 h