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1

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

2

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

SciTech Connect

We present initial performance results for a new multi-layer PET detector module consisting of an array of 3 mm square by 30 mm deep BGO crystals coupled on one end to a single photomultiplier tube and on the opposite end to an array of 3 mm square silicon photodiodes. The photomultiplier tube provides an accurate timing pulse and energy discrimination for the all the crystals in the module, while the silicon photodiodes identify the crystal of interaction. When a single BGO crystal at +25[degree]C is excited with 511 key photons, we measure a photodiode signal centered at 700 electrons (e[sup [minus

Moses, W.W.; Derenzo, S.E. (Lawrence Berkeley Lab., CA (United States)); Nutt, R.; Digby, W.M.; Williams, C.W.; Andreaco, M. (CTI, Inc., Knoxville, TN (United States))

1992-11-01

3

A fast X-ray detector using silicon avalanche photodiodes of 64-pixel linear array  

NASA Astrophysics Data System (ADS)

We have developed a silicon avalanche-photodiode (Si-APD) array detector operated in the linear mode for time-resolved measurements using pulsed synchrotron X-rays. The Si-APD detector had 64 pixels of a linear array, where the pixel size was 100 ?m by 200 ?m with a 50-?m gap between pixels and a depleted thickness was 10 ?m. A nanosecond response of the array detector is extremely valuable for time-resolved X-ray diffraction measurements in the multi-bunch mode operation of a 500M-Hz synchrotron ring. In order to apply the APD detector for the time-resolved diffraction measurements with 2-ns pulse-pair resolving time and a count rate of more than 10 s-1, an ultra fast ASIC has newly been developed for processing a nanosecond-width pulse from each pixel of the Si-APD array. A prototype system had a 10-ns time resolution and a high count-rate of more than 107 s-1/pixel in the first test measurement using synchrotron X-ray beam.

Kishimoto, S.; Yonemura, H.; Adachi, S.; Shimazaki, S.; Ikeno, M.; Saito, M.; Taniguchi, T.; Tanaka, M.

2013-03-01

4

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

PubMed

Avalanche photodiodes (APDs) have proven to be useful as light detectors for high resolution positron emission tomography (PET). Their compactness makes these devices excellent candidates for replacing bulky photomultiplier tubes (PMTs) in PET systems where space limitations are an issue. The readout of densely packed, 10 x 10 lutetium oxyorthosilicate (LSO) block detectors (crystal size 2.0 x 2.0 x 12 mm3) with custom-built monolithic 3 x 3 APD arrays was investigated. The APDs had a 5 x 5 mm2 active surface and were arranged on a 6.25 mm pitch. The dead space on the edges of the array was 1.25 mm. The APDs were operated at a bias voltage of approximately 380 V for a gain of 100 and a dark current of 10 nA per APD. The standard deviation in gain between the APDs in the array ranged from 1.8 to 6.5% as the gain was varied from 50 to 108. A fast, low-noise, multi-channel charge sensitive preamplifier application-specific integrated circuit (ASIC) was developed for the APD readout. The amplifier had a rise time of 8 ns, a noise floor of 515 e- rms and a 9 e- pF(-1) noise slope. An acquired flood image showed that all 100 crystals from the block detector could be resolved. Timing measurements with single-channel LSO-APD detectors, as well as with the array, against a plastic scintillator and PMT assembly showed a time resolution of 1.2 ns and 2.5 ns, respectively. The energy resolution measured with a single 4.0 x 4.0 x 10 mm3 LSO crystal, wrapped in four-layer polytetrafluoroethylene (PTFE) tape and coupled with optical grease on a single APD of the array, yielded 15% (full width at half maximum, FWHM) at 511 keV. Stability tests over 9 months of operation showed that the APD arrays do not degrade appreciably. These results demonstrate the ability to decode densely packed LSO scintillation blocks with compact APD arrays. The good timing and energy resolution makes these detectors suitable for high resolution PET. PMID:15509067

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

2004-09-21

5

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

NASA Astrophysics Data System (ADS)

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

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

2004-09-01

6

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

SciTech Connect

We present initial performance results for a new multi-layer PET detector module consisting of an array of 3 mm square by 30 mm deep BGO crystals coupled on one end to a single photomultiplier tube and on the opposite end to an array of 3 mm square silicon photodiodes. The photomultiplier tube provides an accurate timing pulse and energy discrimination for the all the crystals in the module, while the silicon photodiodes identify the crystal of interaction. When a single BGO crystal at +25{degree}C is excited with 511 key photons, we measure a photodiode signal centered at 700 electrons (e{sup {minus}}) with noise of 375 e{sup {minus}} fwhm. When a four crystal / photodiode module is excited with a collimated line source of 511 key photons, the crystal of interaction is correctly identified 82% of the time. The misidentification rate can be greatly reduced and an 8{times}8 crystal / photodiode module constructed by using thicker depletion layer photodiodes or cooling to 0{degrees}C.

Moses, W.W.; Derenzo, S.E. [Lawrence Berkeley Lab., CA (United States); Nutt, R.; Digby, W.M.; Williams, C.W.; Andreaco, M. [CTI, Inc., Knoxville, TN (United States)

1992-11-01

7

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

Microsoft Academic Search

Avalanche photodiodes (APDs) have proven to be useful as light detectors for high resolution positron emission tomography (PET). Their compactness makes these devices excellent candidates for replacing bulky photomultiplier tubes (PMTs) in PET systems where space limitations are an issue. The readout of densely packed, 10 × 10 lutetium oxyorthosilicate (LSO) block detectors (crystal size 2.0 × 2.0 × 12

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

2004-01-01

8

Scintillation detectors for operation in high magnetic fields: Recent developments based on arrays of avalanche microchannel photodiodes  

NASA Astrophysics Data System (ADS)

The development of scintillation detectors to be used in a high-magnetic-field environment requires novel photodetectors to substitute photomultiplier tubes (PMTs). Avalanche microchannel photodiodes (AMPDs) are competitive to PMTs in terms of gain and photon detection efficiency, and they are insensitive to magnetic fields. But the small active area of an AMPD (typically from 1 to 10mm) could restrict the field of applications for such a photosensor. In this work we demonstrate that the above restriction can be, to a certain extent, overcome by using AMPD arrays: based on an array of four (1×1mm) AMPDs we built scintillation detectors with promising characteristics.

Scheuermann, R.; Stoykov, A.; Renker, D.; Sadygov, Z.; Mehtieva, R.; Dovlatov, A.; Zhuk, V.

2007-10-01

9

Simultaneous determination of catechins, caffeine and gallic acids in green, Oolong, black and pu-erh teas using HPLC with a photodiode array detector  

Microsoft Academic Search

A simple and fast HPLC method using a photodiode array detector was developed for simultaneous determination of four major catechins, gallic acid and caffeine. After multiple extractions with aqueous methanol and acidic methanol solutions, tea extract was separated within 20 min using a methanol–acetate–water buffer gradient elution system on a C18 column. The sample extraction data demonstrated that the single

Yuegang Zuo; Hao Chen; Yiwei Deng

2002-01-01

10

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

11

Identification of components in Zhi-Zi-Da-Huang decoction by HPLC coupled with electrospray ionization tandem mass spectrometry, photodiode array and fluorescence detectors  

Microsoft Academic Search

High-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) in positive and negative ion mode and photodiode array (PDA) and fluorescence detectors (FD) was applied to simultaneously characterise thirty active components in Zhi-Zi-Da-Huang decoction (ZZDHD). The analysis was preformed on a Lichrospher C18 column (4.6mm×250mm, 5?m) using a binary eluent (0.1% aqueous acetic acid (A) and

Hang Wang; Fang Feng

2009-01-01

12

Instrumentation: Photodiode Array Detectors in UV-VIS Spectroscopy. Part II.  

ERIC Educational Resources Information Center

|A previous part (Analytical Chemistry; v57 n9 p1057A) discussed the theoretical aspects of diode ultraviolet-visual (UV-VIS) spectroscopy. This part describes the applications of diode arrays in analytical chemistry, also considering spectroelectrochemistry, high performance liquid chromatography (HPLC), HPLC data processing, stopped flow, and…

Jones, Dianna G.

1985-01-01

13

Photon detection with high gain avalanche photodiode arrays  

SciTech Connect

The detection of light emitted in fast scintillating fibers and Cerenkov radiators used for fiber calorimetry and tracking applications in high energy colliders, requires fast detector arrays with high sensitivity to short wavelength photons. Photomultiplier tubes, the traditional imaging detectors for short wavelength optical radiation, have limited spatial resolution and require expensive anti-magnetic shielding. The authors report on short wavelength sensitivity improvement and detection efficiency performance for a novel p-n junction planar structure silicon avalanche photodiode (APD) array, operated in Geiger mode. The APD array provides a high sensitivity detector for applications requiring the detection of light spatial distributions with single photon sensitivity.

Vasile, S.; Gothoskar, P.; Farrell, R. [Radiation Monitoring Devices, Inc., Watertown, MA (United States); Sdrulla, D. [Advanced Power Technology, Bend, OR (United States)

1998-06-01

14

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.

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

2012-01-01

15

Characterization of germanium photodiodes and trap detector  

Microsoft Academic Search

We have developed and characterized new detectors based on germanium (Ge) photodiodes to be used in the wavelength region between 900 and 1650 nm. The effects of spatial uniformity, temperature and low shunt resistance on the spectral responsivity measurements are studied. Our results for the spatial uniformities show improvements as compared with earlier studies. The spectral reflectances of a Ge

A. Lamminpää; M. Noorma; T. Hyyppä; F. Manoocheri; P. Kärhä; E. Ikonen

2006-01-01

16

Fingerprint analysis of Hibiscus mutabilis L. leaves based on ultra performance liquid chromatography with photodiode array detector combined with similarity analysis and hierarchical clustering analysis methods  

PubMed Central

Background: A method for chemical fingerprint analysis of Hibiscus mutabilis L. leaves was developed based on ultra performance liquid chromatography with photodiode array detector (UPLC-PAD) combined with similarity analysis (SA) and hierarchical clustering analysis (HCA). Materials and Methods: 10 batches of Hibiscus mutabilis L. leaves samples were collected from different regions of China. UPLC-PAD was employed to collect chemical fingerprints of Hibiscus mutabilis L. leaves. Results: The relative standard deviations (RSDs) of the relative retention times (RRT) and relative peak areas (RPA) of 10 characteristic peaks (one of them was identified as rutin) in precision, repeatability and stability test were less than 3%, and the method of fingerprint analysis was validated to be suitable for the Hibiscus mutabilis L. leaves. Conclusions: The chromatographic fingerprints showed abundant diversity of chemical constituents qualitatively in the 10 batches of Hibiscus mutabilis L. leaves samples from different locations by similarity analysis on basis of calculating the correlation coefficients between each two fingerprints. Moreover, the HCA method clustered the samples into four classes, and the HCA dendrogram showed the close or distant relations among the 10 samples, which was consistent to the SA result to some extent.

Liang, Xianrui; Ma, Meiling; Su, Weike

2013-01-01

17

Polychromatic flow cytometry with an avalanche photodiode array  

NASA Astrophysics Data System (ADS)

Multi parameter flow cytometry enables detailed identification of cell type and function based on fluorescence of antibody conjugated dye labels. Current instruments use photomultiplier tube detectors to measure up to eight fluorescent labels from a single excitation source. We demonstrate polychromatic flow cytometry using a 14-element avalanche photodiode (APD) array coupled with a dispersive optical grating. Forward scatter, side scatter, and 14 fluorescence channels over the 530 to 800 nm spectral range are recorded using a 16 channel electronics console for simultaneous event capture. The APD detector elements have a working spectral range from 400 nm to 1050 nm. Results are presented for flow cytometry measurements of Spherotech UltraRainbow test beads, quantum dot labeled polystyrene spheres, and cells with antibody conjugated dye labels. The flow cytometry test bead measurements illustrate the sensitivity and spectral resolution of the APD detector array. The application of the instrument is demonstrated by identifying CD4 positive lymphocyte populations in normal human whole blood samples.

Lawrence, William G.; Varadi, Gyula; Entine, Gerald; Podniesinski, Edward; Wallace, Paul K.

2008-03-01

18

Evaluation of reflective separators for arrays of small crystals used with avalanche photodiodes  

Microsoft Academic Search

Thin, highly reflective, opaque separators are required for compact arrays of small discrete scintillation crystals used in conjunction with pixellated photodiode readouts in high-resolution imaging applications. Mechanical stability, individual detector performance, and cost are the main factors to be considered in the choice of a suitable separator. Five different types of reflective separators were tested with 4×4 arrays of BGO,

C. M. Pepin; R. Lecomte; D. Krus; L. Perna; W. Novak

2000-01-01

19

A polychromator-type near-infrared spectrometer with a high-sensitivity and high-resolution photodiode array detector for pharmaceutical process monitoring on the millisecond time scale  

NASA Astrophysics Data System (ADS)

In the fine chemicals industry, particularly in the pharmaceutical industry, advanced sensing technologies have recently begun being incorporated into the process line in order to improve safety and quality in accordance with process analytical technology. For estimating the quality of powders without preparation during drug formulation, near-infrared (NIR) spectroscopy has been considered the most promising sensing approach. In this study, we have developed a compact polychromator-type NIR spectrometer equipped with a photodiode (PD) array detector. This detector is consisting of 640 InGaAs-PD elements with 20-?m pitch. Some high-specification spectrometers, which use InGaAs-PD with 512 elements, have a wavelength resolution of about 1.56 nm when covering 900-1700 nm range. On the other hand, the newly developed detector, having the PD with one of the world's highest density, enables wavelength resolution of below 1.25 nm. Moreover, thanks to the combination with a highly integrated charge amplifier array circuit, measurement speed of the detector is higher by two orders than that of existing PD array detectors. The developed spectrometer is small (120 mm × 220 mm × 200 mm) and light (6 kg), and it contains various key devices including the high-density and high-sensitivity PD array detector, NIR technology, and spectroscopy technology for a spectroscopic analyzer that has the required detection mechanism and high sensitivity for powder measurement, as well as a high-speed measuring function for blenders. Moreover, we have evaluated the characteristics of the developed NIR spectrometer, and the measurement of powder samples confirmed that it has high functionality.

Murayama, Kodai; Genkawa, Takuma; Ishikawa, Daitaro; Komiyama, Makoto; Ozaki, Yukihiro

2013-02-01

20

Depth of interaction resolution measurements for a high resolution PET detector using position sensitive avalanche photodiodes  

Microsoft Academic Search

We explore dual-ended read out of LSO arrays with two position sensitive avalanche photodiodes (PSAPDs) as a high resolution, high efficiency depth-encoding detector for PET applications. Flood histograms, energy resolution and depth of interaction (DOI) resolution were measured for unpolished LSO arrays with individual crystal sizes of 1.0, 1.3 and 1.5 mm, and for a polished LSO array with 1.3

Yongfeng Yang; Purushottam A. Dokhale; Robert W. Silverman; Kanai S. Shah; Mickel A. McClish; Richard Farrell; Gerald Entine; Simon R. Cherry

2006-01-01

21

SiC avalanche photodiode array with microlenses.  

PubMed

A simple technique to incorporate microlenes with small photodiode arrays is demonstrated and analyzed. Using this method, the fill factor was increased from 2.6% to 22.4% for a two by two array. Simulation results are also shown. The photocurrent with microlens was approximately 8.6 times larger than without the microlens, which is consistent with simulation results. PMID:20589031

Li, Kejia; Liu, Han-Din; Zhou, Qiugui; McIntosh, Dion; Campbell, Joe C

2010-05-24

22

Characterization of InGaAs avalanche photodiode arrays with varying geometries for free-space optical communication  

NASA Astrophysics Data System (ADS)

Photodiode arrays are instrumental in providing pointing and tracking information for free space optical communication systems. Recent advances in the fabrication and development of low noise, high bandwidth avalanche photodiode (APD) arrays have enabled these devices to be used not only as position sensitive detectors (PSD) for tracking but also as communications receivers. In a collaborative effort with Optogration, Inc., the U.S. Naval Research Laboratory has developed avalanche photodiode arrays with three different geometries: a 3x3 square pixel array, a centered hexagonal pixel array, and a 5 pixel concentric array configuration with a center pixel and four periphery pixels. The characterization and performance of each array geometry will be described along with associated front-end and digital electronics. Design tradeoffs for maximizing the performance of a given array geometry will also be discussed.

Ferraro, Mike S.; Burris, Harris R.; Mahon, Rita; Rabinovich, William S.; Freeman, Wade T.; Murphy, James L.; Goetz, Peter G.; Moore, Christopher I.; Thomas, Linda M.; Clark, William R.; Waters, William D.; Vaccaro, Kenneth; Krejca, Brian D.

2012-05-01

23

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

24

Room temperature SWIR sensing from colloidal quantum dot photodiode arrays  

NASA Astrophysics Data System (ADS)

While InGaAs-based focal plane arrays (FPAs) provide excellent detectivity and low noise for SWIR imaging applications, wider scale adoption of systems capable of working in this spectral range is limited by high costs, limited spectral response, and costly integration with Si ROIC devices. RTI has demonstrated a novel photodiode technology based on IR-absorbing solution-processed PbS colloidal quantum dots (CQD) that can overcome these limitations of InGaAs FPAs. The most significant advantage of the CQD technology is ease of fabrication. The devices can be fabricated directly onto the ROIC substrate at low temperatures compatible with CMOS, and arrays can be fabricated at wafer scale. Further, device performance is not expected to degrade significantly with reduced pixel size. We present results for upward-looking detectors fabricated on Si substrates with sensitivity from the UV to ~1.7 µm. We further show devices fabricated with larger size CQDs that exhibit spectral sensitivity that extends from UV to 2 µm.

Klem, Ethan; Lewis, Jay; Gregory, Chris; Cunningham, Garry; Temple, Dorota; D'Souza, Arvind; Robinson, Ernest; Wijewarnasuriya, P. S.; Dhar, Nibir

2013-06-01

25

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

26

Synchronous high-performance liquid chromatography with a photodiode array detector and mass spectrometry for the determination of citrinin, monascin, ankaflavin, and the lactone and acid forms of monacolin K in red mold rice.  

PubMed

The Monascus fermentation product red mold rice (RMR) has been found to contain the cholesterol-lowering agent monacolin K (MK) in both its lactone (MKL) and acid (MKA) forms and the mycotoxin citrinin (CT). The yellow pigments in RMR, namely, monascin (MS) and ankaflavin (AK), have been reported to exhibit antimetastatic and antiangiogenic activities. Currently, MK and these yellow pigments are usually detected in RMR by different analytical methods that are inconvenient, expensive, and time-consuming. The goal of this study was to establish a rapid, synchronous analytical method for determination of the MKA, MKL, MS, AK, and CT levels in RMR. MKA, MKL, MS, AK, and CT were extracted by the same extraction method, then separated by RP-HPLC with a C18 column. The effluent from the column was passed through a photodiode array detector and then introduced directly into a fluorescence detector. The results showed that high recovery rates of MKA, MKL, MS, AK, and CT are possible if RMR powder is extracted with 75% ethanol (10 mL) at 80 degrees C for 30 min. With regard to the optimal conditions of the HPLC, the peaks of MKA, MKL, MS, AK, and CT can be clearly separated from any noise peaks by isocratic elution with a mobile phase comprising 0.05% trifluoroacetic acid in acetonitrile-water (62.5 + 37.5, v/v). PMID:21391495

Wu, Cheng-Lun; Kuo, Yao-Haur; Lee, Chun-Lin; Hsu, Ya-Wen; Pan, Tzu-Ming

27

Pyroelectric Detector Arrays.  

National Technical Information Service (NTIS)

A pyroelectric detector array and the method for making it is described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching...

A. L. Fripp

1980-01-01

28

Determination of phenols in wines by liquid chromatography with photodiode array and fluorescence detection  

Microsoft Academic Search

A reversed-phase LC method, optimised for the separation of trans- and cis-resveratrol, catechin, epicatechin, quercetin and rutin, is reported. Analyses were performed on a reversed-phase column by gradient elution. Detection was carried out by photodiode array, although the use of a fluorimetric detector considerably lowered the detection limits for catechin, epicatechin and both resveratrol isomers. Identification by the two different

Pilar Vinas; Carmen Lopez-Erroz; Juan Jose Marin-Hernandez; Manuel Hernandez-Cordoba

29

[Study on UV-visible DOAS system based on photodiode array (PDA)].  

PubMed

A long-path differential optical absorption spectroscopy (DOAS) system is introduced. A photodiode array is employed as the detector to replace the complicated SD detector which consists of a PMT and a slotted disk. The properties of the detector and the spectrometer unit such as offset, dark current, noise, linearity, resolution, and wavelength range were measured. This system was also tested to measure SO2 and NO2 in the atmosphere. The detection limits of this system for SO2, and NO2 over a 713 m light path were determined. PMID:16379291

Qin, Min; Xie, Pin-hua; Liu, Jian-guo; Liu, Wen-qing; Fang, Wu; Lu, Fan; Li, Ang; Lu, Yi-huai; Wei, Qing-nong; Dou, Ke

2005-09-01

30

Integrated organic optical sensor arrays based on ring-shaped organic photodiodes  

NASA Astrophysics Data System (ADS)

We present an integrated optical sensor platform suitable for the parallel detection of multiple parameters in an array format. This sensor technology combines fluorescent sensor layers with ring-shaped thin-film organic photodiodes (OPDs), serving as integrated fluorescence detectors. The sensing layers are deposited by screen-printing on the upper side of a PET substrate, which is exposed to an analyte, whereas the ring-shaped photodiodes are monolithically integrated, by vapour phase deposition, on the backside of the transparent substrate, in correct alignment to the sensing layers. The monolithic integration of sensor layers and detectors on one common substrate as well as the special ring shaped form of the photodiodes guarantees that a maximum of the fluorescent light emitted from the sensor layers is collected. A key advantage of the above described sensor geometry is the straightforward potential to realise sensor arrays for the parallel detection of multiple parameters: different sensor spots are illuminated by commercial LEDs or alternatively with one large area OLED, and are read-out by individual integrated organic photodiodes, surrounding the respective sensor layers. Three different sensing principles including absorption, fluorescence and surface plasmon resonance can be applied in the same basic sensor platform. The functionality of the concept is demonstrated by an integrated oxygen sensor. Sensor schemes for the analytical parameters carbon dioxide, temperature and ammonia, are proposed. Efficient front end electronics enabling intensity and time domain detection of sensor signals for the testing and characterisation of the integrated sensor devices have been developed.

Sagmeister, Martin; Lamprecht, Bernhard; Kraker, Elke; Haase, Anja; Jakopic, Georg; Köstler, Stefan; Ditlbacher, Harald; Galler, Nicole; Abel, Tobias; Mayr, Torsten

2011-09-01

31

Rapid characterisation and comparison of saponin profiles in the seeds of Korean Leguminous species using ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass spectrometry (UPLC-PDA-ESI/MS) analysis.  

PubMed

The present work was reported on investigation of saponin profiles in nine different legume seeds, including soybean, adzuki bean, cowpea, common bean, scarlet runner bean, lentil, chick pea, hyacinth bean, and broad bean using ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass spectrometry (UPLC-PDA-ESI/MS) technique. A total of twenty saponins were characterised under rapid and simple conditions within 15min by the 80% methanol extracts of all species. Their chemical structures were elucidated as soyasaponin Ab (1), soyasaponin Ba (2), soyasaponin Bb (3), soyasaponin Bc (4), soyasaponin Bd (5), soyasaponin ?g (6), soyasaponin ?g (7), soyasaponin ?a (8), soyasaponin ?g (9), soyasaponin ?a (10), azukisaponin VI (11), azukisaponin IV (12), azukisaponin II (13), AzII (14), AzIV (15), lablaboside E (16), lablaboside F (17), lablaboside D (18), chikusetusaponin IVa (19), and lablab saponin I (20). The individual and total saponin compositions exhibited remarkable differences in all legume seeds. In particular, soyasaponin ?a (8) was detected the predominant composition in soybean, cowpea, and lentil with various concentrations. Interestingly, soybean, adzuki bean, common bean, and scarlet runner bean had high saponin contents, while chick pea and broad bean showed low contents. PMID:24176342

Ha, Tae Joung; Lee, Byong Won; Park, Ki Hun; Jeong, Seong Hun; Kim, Hyun-Tae; Ko, Jong-Min; Baek, In-Youl; Lee, Jin Hwan

2013-09-18

32

A photon-counting avalanche photodiode array with fully integrated active quenching and recharging circuit  

Microsoft Academic Search

The design of a 4 × 1 photon-counting avalanche photodiode array with fully integrated active bias controlling circuit is presented in this paper. The array uses highly sensitive Geiger mode avalanche photodiodes and is capable of detecting four single-photon-level optical signals simultaneously. The photodiode pixels can work either in parallel mode or independently because of the separate gate configuration. The

F. Lin; M. Mac Sweeney; M. M. Sheehan; A. Mathewson

2005-01-01

33

Ultraviolet Array Detector Research.  

National Technical Information Service (NTIS)

Under this contract multiple tasks were performed in support of the development of Ultraviolet Array Detector Research. The Horizon Ultraviolet Program instrumentation was supported through a second Space shuttle launch. An Ebert-Fastie spectrometer was m...

M. Gangl M. Bullinger R. Cundiff J. McKay J. Middlestadt

1995-01-01

34

Wide Dynamic Range Array Detector for Absorbance and Rotation Spectrometry.  

National Technical Information Service (NTIS)

Photodiode detectors have a limited dynamic range relative to a photomultiplier tube. Sensitivity (in terms of intensity) can be adjusted by changing the integration time, but the integration time for all diodes in array detector is the same for any given...

P. J. Aiello C. G. Enke

1983-01-01

35

A room temperature LSO/PIN photodiode PET detector module that measures depth of interaction  

SciTech Connect

The authors present measurements of a 4 element PET detector module that uses a 2 x 2 array of 3 mm square PIN photodiodes to both measure the depth of interaction (DOI) and identify the crystal of interaction. Each photodiode is coupled to one end of a 3 x 3 x 25 mm LSO crystal, with the opposite ends of all 4 crystals attached to a single PMT that provides a timing signal and initial energy discrimination. Each LSO crystal is coated with a ``lossy`` reflector, so the ratio of light detected in the photodiode and PMT depends on the position of interaction in the crystal, and is used to determine this position on an event by event basis. This module is operated at +25 C with a photodiode amplifier peaking time of 2 {micro}s. When excited by a collimated beam of 511 keV photons at the photodiode end of the module (i.e. closest to the patient), the DOI resolution is 4 mm fwhm and the crystal of interaction is identified correctly 95% of the time. When excited at the opposite end of the module, the DOI resolution is 13 mm fwhm and the crystal of interaction is identified correctly 73% of the time. The channel to channel variations in performance are minimal.

Moses, W.W.; Derenzo, S.E. [Lawrence Berkeley Lab., CA (United States); Melcher, C.L.; Manente, R.A. [Schlumberger-Doll Research, Ridgefield, CT (United States)

1995-08-01

36

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 8x1013 Jones with a differential resistance-area product greater than 3x107 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 SiO2 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.

2008-05-01

37

CMOS Geiger-mode avalanche photodiode detectors for time and intensity resolved measurements  

NASA Astrophysics Data System (ADS)

Geiger-mode avalanche photodiode detectors are produced using standard CMOS fabrication methods. We have produced integrated circuits that include the Geiger-mode photodetector and digital signal processing circuits. Our current design includes sixteen photon counting detector elements, with bias control, active quenching circuits, and integrated counters at each pixel. The detectors are used to measure chemiluminescence from horseradish peroxidase conjugated antibodies in sub-microliter samples using an optical waveguide. The detector array has been coupled with an external field programmable gate array (FPGA) to perform multi-channel, all digital, time resolved fluorescence measurements of quantum dot nanoparticles and the pH dependence of the fluorescence lifetime of fluorescein dye.

Lawrence, William G.; Tozian, Tani; Stapels, Christopher; Christian, James F.; Derderian, Gregory D.; Derderian, Jeffrey P.; Varadi, Gyula

2010-02-01

38

Coincident observations of lightning by the FORTE photodiode detector, the New Mexico Tech Lightning Mapping Array and the NLDN during STEPS  

Microsoft Academic Search

Opportunities for observation of lightning simultaneously from space and ground are relatively rare. One such opportunity for “ground truth” occurred during the STEPS field program. On 25 June, 2000 the FORTE Satellite passed over a storm that was also observed by a VHF Lightning Mapping Array (LMA). Of the 190 flashes mapped during the 2 minute 45 second pass, 26

Cynthia M. M. Noble; William H. Beasley; Susan E. Postawko; T. E. L. Light

2004-01-01

39

Coincident observations of lightning by the FORTE photodiode detector, the New Mexico Tech Lightning Mapping Array and the NLDN during STEPS  

Microsoft Academic Search

Opportunities for observation of lightning simultaneously from space and ground are relatively rare. One such opportunity for ``ground truth'' occurred during the STEPS field program. On 25 June, 2000 the FORTE Satellite passed over a storm that was also observed by a VHF Lightning Mapping Array (LMA). Of the 190 flashes mapped during the 2 minute 45 second pass, 26

Cynthia M. M. Noble; William H. Beasley; Susan E. Postawko; T. E. L. Light

2004-01-01

40

Detector array design  

SciTech Connect

Neutron scattering facility at Oak-Ridge National is used to measure residual stresses in many different materials. Neutron beam from the reactor can be used to penetrate the inner atomic distances of metals which then can be diffracted to a detector to measure the strain. The strain data later can be converted to stresses. The facility currently uses only one detector to carry the measurement. By designing an array of detectors data can be obtained at a much faster rate and or having a much better and improved resolution. The purpose of this report is to show design of such array of detectors and their movements (rotation) for possible maximum data collection at a faster rate.

Lari, S.

1996-02-01

41

High-performance SWIR sensing from colloidal quantum dot photodiode arrays  

NASA Astrophysics Data System (ADS)

RTI has demonstrated a novel photodiode technology based on IR-absorbing solution-processed PbS colloidal quantum dots (CQD) that can overcome the high cost, limited spectral response, and challenges in the reduction in pixel size associated with InGaAs focal plane arrays. The most significant advantage of the CQD technology is ease of fabrication. The devices can be fabricated directly onto the ROIC substrate at low temperatures compatible with CMOS, and arrays can be fabricated at wafer scale. Further, device performance is not expected to degrade significantly with reduced pixel size. We present results for upward-looking detectors fabricated on Si substrates with sensitivity from the UV to ~1.7 ?m, compare these results to InGaAs detectors, and present measurements of the CQD detectors temperature dependent dark current.

Klem, Ethan; Lewis, Jay; Gregory, Chris; Cunningham, Garry; Temple, Dorota; D'Souza, Arvind; Robinson, Ernest; Wijewarnasuriya, P. S.; Dhar, Nibir

2013-09-01

42

Development of scintillation detectors based on avalanche microchannel photodiodes  

NASA Astrophysics Data System (ADS)

Avalanche Microchannel PhotoDiodes (AMPDs) are solid state photodetectors with high internal gain and a density of independent channels up to 104/mm2. They are potential substitutes for photomultiplier tubes in a wide variety of applications in nuclear physics and nuclear medicine, especially when fine segmentation of the detectors and their operation in high magnetic fields is required. In this work, we study the performance of a detector based on a LYSO (2×2×10 mm3) scintillation crystal and AMPD at detection of 511 keV ?-quanta. The detector shows linear energy response, an energy resolution of ˜12%, and sub-nanosecond time resolution. These characteristics are encouraging for using AMPDs in detector systems of positron emission tomographs (PET) of the next generation.

Britvitch, I.; Lorenz, E.; Olshevski, A.; Renker, D.; Sadygov, Z.; Scheuermann, R.; Stoykov, A.; Werner, A.; Zheleznykh, I.

2007-02-01

43

Photon detection with high gain avalanche photodiode arrays  

Microsoft Academic Search

The detection of light emitted in fast scintillating fiber bundles and Cerenkov radiators used for fiber calorimetry and tracking applications requires fast detector arrays with high sensitivity to short-wavelength photons. Photomultiplier tube arrays, the traditional imaging detectors for short-wavelength optical radiation, have limited spatial resolution and require expensive anti-magnetic shielding. We report on short-wavelength sensitivity improvement and detection efficiency performance

S. Vasile; P. Gothoskar; D. Sdrulla; R. Farrell

1997-01-01

44

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

45

Photodetectors Based on Back-Illuminated Silicon Photodiode Arrays for X-ray Imaging Systems  

Microsoft Academic Search

The properties of ultra-thin, pin photodiode arrays designed for CT and other scintillator-based applications are discussed. The photodiode arrays were built on 75-mum thick single Si dies. The element size varied from over 1.5 mm to 200-mum with the gaps (dead spaces) between adjacent elements as small as 25 mum. The most pronounced features of the arrays described here include

I. Goushcha; B. Tabbert; A. Popp; A. O. Goushcha

2007-01-01

46

Germanium detector array — GERDA  

NASA Astrophysics Data System (ADS)

GERDA will be a new experiment at the Laboratori Nazionali del Gran Sasso (LNGS) to study neutrinoless double beta decay of 76Ge at background levels <10-3 cts/(keV kg y) at Q=2039keV, two orders of magnitude lower than in the previous experiments. Bare Ge-diodes, enriched to 86% in 76Ge, are operated in liquid argon complemented by a water shield to reduce the external backgrounds. Intrinsic backgrounds will be suppressed by the pulse shape analysis and segmented electrodes. In GERDAs first phase, the detector array will consist of the existing and refurbished detectors of the previous Heidelberg-Moscow and IGEX experiments. After one year of measurement, the setup should allow us to scrutinize the claimed observation of 0??? decay in 76Ge. In its second phase, GERDA will use an additional set of new enriched 76Ge crystals, as segmented or point contact detectors. After 100 kg y the sensitivity will be T>1.5?1026y; this corresponds to an effective Majorana mass range from 0.1 eV to 0.2 eV.

Jochum, J.

2010-04-01

47

A cesium iodide (thallium)-photodiode array for remote geochemical analysis  

NASA Astrophysics Data System (ADS)

To improve our understanding of the mechanism of the formation of the Solar System, information is needed on the global chemical composition of the planets outside of the Earth-Moon system. Thus, the measurement of the chemical composition of Mars and Mercury is a high priority for both the ESA and NASA space programmes. Remote geochemical analysis (RGA), by neutron activation gamma-ray spectroscopy, is a proven technique for remotely mapping the chemical composition of a planet with a thin or no atmosphere and as a result future missions to other terrestrial planets will probably include a gamma-ray spectrometer. The spectrometer must have sufficient sensitivity to resolve the most important emission fines radiating from the planet, whilst remaining within the mass, power and budget limitations of the mission specification. Therefore, there is a requirement for a spectrometer that will provide sufficient sensitivity, to determine the ratio's of elements such as Fe, O, Si and the naturally occurring radionucides K, U and Th, without incurring the high costs of a cooled HPGe detector. This work considers the factors that will determine the sensitivity of a scintillator gamma-ray spectrometer for RGA and demonstrates that a 61 element, pixelated, CsI(Tl)-phtodiode array will have a greater sensitivity than an, equivalent mass, NaI(Tl)-PMT or BGO-PMT detector. This is a result of the high mass ratio of sensitive material in the CsI(Tl)-photodiode array and the improved energy resolution, when compared to a NaI(Tl)-PMT detector, at energies above 2MeV. A prototype 7-element array has been designed, constructed and, tested at energies up to 4.44MeV, to demonstrate the potential performance of a larger 61-element array. The energy resolution of the 7 element array was found to be 2.93% FWHM at 4.44MeV, when operating in simple summation mode, which compares to 3.5% FWHM for a 2' NaI(Tl)-PMT detector. Consideration is also given to the different methods of spectral analysis that may be utilised when using a pixelated CsI(Tl) array and the benefits that may be gained when applying a spectral deconvolution algorithm to the recorded spectra. The process has been used to deconvolve spectra recorded by a small 1cc CsI(Tl)- photodiode detector and the 7-element array. The deconvolution resulted in a pseudo energy resolution for the 1cc detector of 2.3% FWHM at 662keV and a pseudo energy resolution, for the 7 element array, of <2% FWHM at 4.44MeV. Finally, a large CsI(Tl) array may have the potential to be used for terrestrial applications such as the remote inspection of cargo containers by neutron activation analysis. The design of a potential detector is presented and the performance calculated using Monte-Carlo simulations.

Evans, Robert James

48

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

SciTech Connect

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 the cross-path wind speed. Close agreement was found between these two measures of the wind.

Porch, W.M.; Green, T.J.

1980-04-01

49

The GERmanium detector array, GERDA  

Microsoft Academic Search

The GERmanium Detector Array, GERDA, is a new experiment which is currently being built at the INFN LNGS Laboratory in Italy with the aim to search for neutrinoless double beta-decay of 76Ge. Unique features of the experiment are (1) to operate germanium detectors directly inside a bath of liquid argon, and (2) to use segmented germanium detectors. The background level

K. Kröninger

2008-01-01

50

Bunch-purity measurements of synchrotron X-ray beams with an avalanche photodiode detector  

Microsoft Academic Search

The bunch purity of synchrotron X-ray beams has been measured with an avalanche photodiode (APD) detector. The APD detector has several advantages for measurements of the bunch structure in a storage ring: the detector has a good time resolution of 100 ps (FWHM) and very low noise level. Moreover, the peak profile by the present APD device has only a

Shunji Kishimoto

1994-01-01

51

Bright Spots: UV Measurements Using a Vacuum Photodiode Array  

NASA Astrophysics Data System (ADS)

Solar coronal loops typically erupt abruptly after long quiescent periods. Such eruptions might be initiated by interactions between adjacent loops; this possibility was explored in a laboratory experiment where two plasma-filled flux tubes merge in either a co-or counter-helicity arrangement (J.F. Hansen, S.K.P. Tripathi, and P.M. Bellan, Phys. Plasma 2, 3177(2004)). The latter arrangement produces a bright region with enhanced soft x-ray emission. We investigate such mergings with a new array of EUV photo-detectors (based on S.J. Zweben, R.J. Taylor, Plasma Physics, Vol. 23, No. 4(1981)) that provides spatially and temporally resolved measurements of radiation between 10 and 120 nm. The detector boasts a sub-microsecond rise-time and provides a large signal without amplification. The detector is shielded from the charged particle background by permanent magnets. A novel two-step scheme diverts RF ground loop currents and greatly improves the signal-to-noise ratio.

Perkins, Rory; Bellan, Paul

2010-11-01

52

Massively parallel MRI detector arrays.  

PubMed

Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas via reception, 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

2013-02-07

53

Massively parallel MRI detector arrays  

NASA Astrophysics Data System (ADS)

Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas via reception, 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.

Keil, Boris; Wald, Lawrence L.

2013-04-01

54

Using Photodiodes in the Laboratory.  

ERIC Educational Resources Information Center

|Describes the most popular optical detector in the design of photodiode detector circuits. Discusses how a photodiode works, points to consider in the design of a photodiode, and photodiode hybrids. (AIM)|

Jenkins, T. E.

1995-01-01

55

A bench-top megavoltage fan-beam CT using CdWO{sub 4}-photodiode detectors. I. System description and detector characterization  

SciTech Connect

We describe the components of a bench-top megavoltage computed tomography (MVCT) scanner that uses an 80-element detector array consisting of CdWO{sub 4} scintillators coupled to photodiodes. Each CdWO{sub 4} crystal is 2.75x8x10 mm{sup 3}. The detailed design of the detector array, timing control, and multiplexer are presented. The detectors show a linear response to dose (dose rate was varied by changing the source to detector distance) with a correlation coefficient (R{sup 2}) nearly unity with the standard deviation of signal at each dose being less than 0.25%. The attenuation of a 6 MV beam by solid water measured by this detector array indicates a small, yet significant spectral hardening that needs to be corrected before image reconstruction. The presampled modulation transfer function is strongly affected by the detector's large pitch and a large improvement can be obtained by reducing the detector pitch. The measured detective quantum efficiency at zero spatial frequency is 18.8% for 6 MV photons which will reduce the dose to the patient in MVCT applications. The detector shows a less than a 2% reduction in response for a dose of 24.5 Gy accumulated in 2 h; however, the lost response is recovered on the following day. A complete recovery can be assumed within the experimental uncertainty (standard deviation <0.5%); however, any smaller permanent damage could not be assessed.

Rathee, S.; Tu, D.; Monajemi, T.T.; Rickey, D.W.; Fallone, B.G. [Department of Medical Physics, Cross Cancer Institute, Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, Departments of Oncology and Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, Departments of Oncology and Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, CancerCare Manitoba, 675 McDermot Ave, Winnipeg, Manitoba, R3E 0V9 (Canada); Departments of Radiology and Physics, University of Manitoba (Canada); Department of Medical Physics, Cross Cancer Institute, Departments of Oncology and Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

2006-04-15

56

AlGaN p-i-n Photodiode Arrays for Solar-Blind Applications  

Microsoft Academic Search

This paper presents UV imaging results for a 256×256 AlGaN Focal Plane Array that uses a back-illuminated AlGaN heterostructure p-i-n photodiode array, with 30×30 µm² unit cells, operating at zero bias voltage, with a narrow-band UV response between 310 and 325 nm. The 256×256 array was fabricated from a multilayer AlGaN film grown by MOCVD on a sapphire substrate. The

P. Lamarre; A. Hairston; S. Tobin; K. K. Wong; M. F. Taylor; A. K. Sood; M. B. Reine; M. J. Schurman; I. T. Ferguson; R. Singh

2001-01-01

57

The HELIOS silicon detector array  

NASA Astrophysics Data System (ADS)

A prototype detector array has been constructed for use in the Helical Orbit Spectrometer (HELIOS) at the ATLAS facility at Argonne National Laboratory. HELIOS is a high-resolution spectrometer for use in studying reactions in inverse kinematics on hydrogen or helium targets. HELIOS consists of a large bore, 3T superconducting solenoid oriented with the magnetic and beam axes aligned. The detector array is comprised of four modules each with six 1.2 x 5.6cm position sensitive silicon detectors. On each module, the detectors were affixed with conductive epoxy and wire bonded to custom made multi-layer printed circuit boards. To keep the radial extent of the detectors to a minimum, the modules were assembled on a hollow 1.6 x 1.6 x 68.8 cm aluminum rail centered on the beam axis located upstream from the target. To characterize the timing, position, and energy resolutions, the detectors were evaluated at the Western Michigan University Accelerator Laboratory using elastic proton-proton scattering. The construction, assembly and preliminary testing of the array will be discussed.

Marley, S. T.

2008-10-01

58

Rapid identification of teleocidins in fermentation broth using HPLC photodiode array and LC\\/MS methodology  

Microsoft Academic Search

Summary During the course of screening for inhibitors of phorbol ester binding to protein kinase C, several actinomycete cultures were discovered that produce active metabolites. HPLC coupled to photodiode array and LC\\/MS techniques were applied to broth extracts to identify the presence of indolactams belonging to the teleocidin family. Various members of this family were rapidly identified from crude broth

David M. Sedlock; Howard H. Sun; William F. Smith; Kenji Kawaoka; Amanda M. Gillum; Ray Cooper

1992-01-01

59

Potential of high-performance liquid chromatography with photodiode array detection in forensic toxicology  

Microsoft Academic Search

The potentials and limitations of high-performance liquid chromatography-photodiode array detection are highlighted in respect to its use in the analysis of different biological matrices followed by the identification of unknowns. The logical analytical approach used in clinical and forensic toxicology, vital for the identification of one or more toxic substances as a cause of intoxication, is largely based on both

Willy E. Lambert; Jan F. Van Bocxlaer; André P. De Leenheer

1997-01-01

60

High resolution interrogation technique based on linear photodiode array spectrometer for fiber Bragg grating sensors  

Microsoft Academic Search

A linear photodiode array spectrometer based, high resolution interrogation technique for fiber Bragg grating sensors is demonstrated. Spline interpolation and Polynomial Approximation Algorithm (PAA) are applied to the data points acquired by the spectrometer to improve the original PAA based interrogation method. Thereby fewer pixels are required to achieve the same resolution as original. Theoretical analysis indicates that if the

Songwei Zhang; Yuliang Liu; Fang Li

2007-01-01

61

High-Current Backside-Illuminated Photodiode Array Module for Optical Analog Links  

Microsoft Academic Search

We have developed a high-current photodiode (PD) array module that consists of a beam splitter, which splits a light beam from a single-mode fiber into four beams with identical powers, a backside-illuminated InGaAs p-i-n PD array, and a two-stage Wilkinson RF power combiner. To obtain a linear PD response, the PD is equipped with a partially depleted absorber, which reduces

Shigetaka Itakura; Kiyohide Sakai; Tsutomu Nagatsuka; Eitaro Ishimura; Masaharu Nakaji; Hiroshi Otsuka; Kazutomi Mori; Yoshihito Hirano

2010-01-01

62

Development of 50 x 50 fiber-array photodiode camera  

NASA Astrophysics Data System (ADS)

Optical imaging of neural network activity using voltage sensitive dyes is expected to be easier than the current electrode method to get multiple point information simultaneously. A high- speed camera is needed to capture a change of a fluorescence image caused by a potential change accompanying neuronal activity. The electrical excitation of a neuron lasts for a few milliseconds and the concomitant fluorescence change is reported to be a few percent or less of its total intensity. A 50 X 50 photodiode camera is specifically designed for this purpose. This camera can take pictures with a 12 bit accuracy every 256 microsecond(s) for about 1 sec(4096 pictures). The epi-illuminated fluorescence image through an objective lens is focused on the end-plate of a 50 X 50 plastic optical fiber bundle. Individual photodiodes and ac-coupled amplifiers are connected to each optical fiber. The time-dependent portion of each signal is transferred to one of the ten 12-bit AD converters through a three-stage multiplexer, and digitally stored in a 20 MBytes RAM. We demonstrated the ability of the camera by capturing membrane potential images of sea urchin eggs induced by an external electric field.

Takahashi, Mutsuji; Tsuchiya, H.; Hosoi, Shigeru; Hayakawa, Tsuyoshi

1993-01-01

63

Simultaneous determination of five aluminum lake dyes in chewing gum by HPLC with photodiode array detection.  

PubMed

A simple and rapid method has been developed and validated for the determination of five food aluminum lake dyes (Tartrazine Al lake, Sunset Yellow Al lake, Ponceau 4R Al lake, Allura Red Al lake and Brilliant Blue Al lake) in chewing gum. The dye portions of the target aluminum lakes were simultaneous extracted with 0.25 M NaOH and cleaned up by liquid-liquid extraction with dichloromethane, followed by further purification using Oasis WAX solid-phase extraction (SPE) cartridges. Analytes were separated by HPLC using an Inertsil ® ODS-3 column coupled to a photodiode array detector. The amounts of the aluminum lake dyes were finally quantified and indicated as their dye portions using corresponding calibration curves over ranges of 0.5 to 50 µg ml(-1), with correlation coefficients >0.9999. Recoveries of the dye parts in aluminum lake dyes (spiked at levels of 1, 5, 25 µg g(-1)) ranged from 72.5 to 116.4%, with relative standard deviations between 0.9 and 6.5%. Limits of detection and limits of quantification for all analytes were 0.15 and 0.50 µg g(-1), respectively. This method was successfully applied in real samples of chewing gum. PMID:21707267

Yang, Yi; Yin, Jie; Shao, Bing

2011-06-27

64

Optical observations of terrestrial lightning by the FORTE satellite photodiode detector  

Microsoft Academic Search

We review data from observations of terrestrial lightning obtained by the FORTE satellite between September 1997 and January 2000. A silicon photodiode detector (PDD) records the intensity-time history of transient optical events occurring within its 80 circular field of view. This field of view corresponds to a circle on the Earth's surface having an approximate diameter of 1200 km. We

M. W. Kirkland; D. M. Suszcynsky; J. L. L. Guillen; J. L. Green

2001-01-01

65

Optical observations of terrestrial lightning by the FORTE satellite photodiode detector  

Microsoft Academic Search

We review data from observations of terrestrial lightning obtained by the FORTE satellite between September 1997 and January 2000. A silicon photodiode detector (PDD) records the intensity-time history of transient optical events occurring within its 80° circular field of view. This field of view corresponds to a circle on the Earth's surface having an approximate diameter of 1200 km. We

M. W. Kirkland; D. M. Suszcynsky; J. L. L. Guillen; J. L. Green

2001-01-01

66

High time resolution x-ray measurements with an avalanche photodiode detector  

Microsoft Academic Search

An avalanche photodiode (APD) detector has been developed for x-ray timing measurements with a subnanosecond time resolution. The performance of the APD detector was investigated with synchrotron x-ray beams in multi- and single-bunch runs at the Photon Factory (PF) ring. A time resolution of 0.28 ns (FWHM) and a peak-to-background ratio of more than 107 were obtained from the main

Shunji Kishimoto; Photon Factory

1992-01-01

67

Reliability of InGaAs detectors and arrays  

NASA Astrophysics Data System (ADS)

The mean time to failure (MTTF) for InGaAs planar photodiodes was predicted to be 10 exp 14 hours at room temperature, based on life tests at temperatures of 200, 230, and 250 C (and -12 V reverse bias). This improved value is thought to be due to reductions in leakage current which lead to higher reliability. Significant reduction in background doping of the InGaAs absorption layer and mild doping (about 2 x 10 exp 16/cu cm) of the InP cap layer led to lower leakage currents. The typical room temperature leakage current of a 300 micron diameter photodiode is 300 pA at -5 V, and a 25 percent increase in this value constitutes a failure. For InGaAs photodiode arrays, an additional criterion of failure, 'popcorn noise' is introduced. Popcorn noise exhibits random charge (current) fluctuations in a p-n junction. The predicted MTTF for a 256-element In(0.53)Ga(0.47)As array is 100 hrs for one diode failure and 3 x 10 exp 9 hrs for five diode failures. Undegraded operation was observed with a group of In(0.8)Ga(0.2)As detectors (which absorb light out to 2.6 microns) after 8000 hrs at 125 C.

Joshi, A. M.; Olsen, G. H.; Patil, S. R.

1992-02-01

68

The GERmanium detector array, GERDA  

NASA Astrophysics Data System (ADS)

The GERmanium Detector Array, GERDA, is a new experiment which is currently being built at the INFN LNGS Laboratory in Italy with the aim to search for neutrinoless double beta-decay of 76Ge. Unique features of the experiment are (1) to operate germanium detectors directly inside a bath of liquid argon, and (2) to use segmented germanium detectors. The background level is expected to be two orders of magnitude below that of recent experiments. This results in an estimated sensitivity to the half-life of T1/2 > 13.5 · 1025 y for the envisioned exposure of 100 kg·y, corresponding to an effective Majorana neutrino mass of approximately 130 meV.

Kröninger, K.

2008-05-01

69

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

70

Integrating Pixel Array Detector Development  

NASA Astrophysics Data System (ADS)

X-ray experiments are very frequently detector limited at storage ring synchrotron radiation sources, and will be even more so at future x-ray free electron laser and energy recovery linac sources. Limitations most frequently arise from the inability of detectors to efficiently collect and process data at the rates at which the data can be generated. Two bump-bonded silicon pixel array detectors (PADs) are being developed at Cornell University that will greatly enhance data collection capabilities. In these PADs x-rays are converted to electrical signals in a pixelated layer of high resistivity silicon, each pixel of which is connected by a metal solder ``bump'' to a corresponding pixel in a CMOS silicon integrated circuit. Each CMOS pixel contains its own data handling and processing electronics. Since all pixels operate in parallel, the PAD is capable of handling extremely high data throughput. The PAD pixels feature integrating analog front-end electronics which allow extremely high instantaneous count-rates, yet sufficiently high signal-to-noise to be able to detect single x-ray photons. The first PAD is designed for coherent x-ray imaging experiments at the Linac Coherent Light Source (LCLS) at SLAC. This detector frames continuously at the LCLS rate of 120 Hz, where the data for each frame can arrive in femtoseconds. The second detector, a result of a collaboration with the Area Detector Systems Corporation, is designed for high throughput protein crystallography experiments. Both detectors are described, and test data is provided. The capabilities of the detectors suggest a variety of new applications, some of which will be discussed.

Gruner, Sol

2009-03-01

71

Filter-free integrated sensor array based on luminescence and absorbance measurements using ring-shaped organic photodiodes.  

PubMed

An optical waveguiding sensor array featuring monolithically integrated organic photodiodes as integrated photo-detector, which simplifies the readout system by minimizing the required parts, is presented. The necessity of any optical filters becomes redundant due to the proposed platform geometry, which discriminates between excitation light and sensing signal. The sensor array is capable of measuring luminescence or absorption, and both sensing geometries are based on the identical substrate. It is demonstrated that background light is virtually non-existent. All sensing and waveguide layers, as well as in- and out-coupling elements are assembled by conventional screen-printing techniques. Organic photodiodes are integrated by layer-by-layer vacuum deposition onto glass or common polymer foils. The universal and simple applicability of this sensor chip is demonstrated by sensing schemes for four different analytes. Relative humidity, oxygen, and carbon dioxide are measured in gas phase using luminescence-based sensor schemes; the latter two analytes are also measured by absorbance-based sensor schemes. Furthermore, oxygen and pH in aqueous media were enabled. The consistency of calibration characteristics extending over different sensor chips is verified. PMID:22706404

Abel, Tobias; Sagmeister, Martin; Lamprecht, Bernhard; Kraker, Elke; Köstler, Stefan; Ungerböck, Birgit; Mayr, Torsten

2012-06-17

72

A current mode detector array for ?-ray asymmetry measurements  

NASA Astrophysics Data System (ADS)

We have built a CsI(Tl) ?-ray detector array for the NPDGamma experiment to search for a small parity-violating directional asymmetry in the angular distribution of 2.2 MeV ?-rays from the capture of polarized cold neutrons by protons with a sensitivity of several ppb. The weak pion nucleon coupling constant can be determined from this asymmetry. The small size of the asymmetry requires a high cold neutron flux, control of systematic errors at the ppb level, and the use of current mode ?-ray detection with vacuum photodiodes and low-noise solid-state preamplifiers. The average detector photoelectron yield was determined to be 1300 photoelectrons per MeV. The RMS width seen in the measurement is therefore dominated by the fluctuations in the number of ?-rays absorbed in the detector (counting statistics) rather than the intrinsic detector noise. The detectors were tested for noise performance, sensitivity to magnetic fields, pedestal stability and cosmic background. False asymmetries due to gain changes and electronic pickup in the detector system were measured to be consistent with zero to an accuracy of 10 in a few hours. We report on the design, operating criteria, and the results of measurements performed to test the detector array.

Gericke, M. T.; Blessinger, C.; Bowman, J. D.; Gillis, R. C.; Hartfield, J.; Ino, T.; Leuschner, M.; Masuda, Y.; Mitchell, G. S.; Muto, S.; Nann, H.; Page, S. A.; Penttilä, S. I.; Ramsay, W. D.; Seo, P.-N.; Snow, W. M.; Tasson, J.; Wilburn, W. S.

2005-03-01

73

Silicon carbide photodiodes: future solar-blind EUV/soft x-ray detectors  

NASA Astrophysics Data System (ADS)

The responsivity of a SiC photodiode was measured with synchrotron radiation in the deep UV and for the first time in the EUV and soft x-ray wavelength regions. A peak responsivity was 200 mA/W at 270 nm wavelength and 60 mA/w at 13 nm in the EUV. Extended measurements at shorter wavelengths demonstrated a responsivity up to 80 mA/W for wavelengths as short as 1.5 nm. The responsivity was calculated by an optical model that accounted for the reflection and absorption of the incident electromagnetic wave, the pair creation energy in the 6H-SiC device, and the variation of the charge collection efficiency (CCE) with depth into the device. The calculated responsivity was in excellent agreement with the measured responsivity and with the structure of the p-n junction photodiode. The measured visible light sensitivity was a factor of 100 lower than that of a silicon photodiode. These new results open up several possible applications for SiC photodiodes, including the selective detection of EUV and soft x-ray radiation without contamination by visible and IR wavelengths. SiC photodiodes have also been proven to withstand prolonged UV exposure and extreme temperatures, thus making them nearly ideal detectors for fiiture solar and space missions where absolutely calibrated EUV and soft x-ray intensities must be accurately measured.

Seely, J. F.; Kjornrattanawanich, Benjawan; Korde, Raj

2005-08-01

74

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

75

Study of dynamical light scattering in phase separating /sup 3/He--/sup 4/He mixtures using linear photodiode arrays  

SciTech Connect

Experimental techniques to study dynamical light scattering phenomena in phase separating /sup 3/He--/sup 4/He liquid mixtures are described. Commercially available self-scanning 512-element linear photodiode arrays are used to record ''snapshots'' of small-angle light scattering patterns with high angular resolution at time intervals as short as 2 ms. Logic circuitry developed for interfacing the photodiode arrays with a digital oscilloscope recorder is described in detail.

Sinha, D.N.; Hoffer, J.K.

1984-06-01

76

High-throughput screening of xanthine oxidase inhibitory properties of drug analogs using photodiode array microchip  

Microsoft Academic Search

We have developed a high-throughput chip-based assay that uses a photodiode array (PDA) microchip system to explore the inhibitory effects of drug analogs on Xanthine oxidase (XO). Inhibitory effects of dithranol (anthracene derivative), aminoglutethimide (anti-steroid), cyclosporine A (immunosuppressant) and naringenin (flavonoid) on XO were elucidated using the chip-based assay in the presence or absence of a free radical scavenging enzyme

Jae Hyung Lee; Jae Ah Kim; Joon Myong Song

2010-01-01

77

First in-beam PET imaging with LSO\\/APD array detectors  

Microsoft Academic Search

The performance and in-beam imaging capabilities of two position-sensitive ?-ray detectors consisting of Hamamatsu avalanche photodiode arrays (S8550) individually coupled to crystals of cerium-doped lutetium oxyorthosilicate (LSO) are presented. The two detectors were operated in coincidence at the medical beam line of the Gesellschaft für Schwerionenforschung, in Darmstadt, Germany. In a first set of experiments, their imaging performance was tested

Paulo Crespo; Maciej Kapusta; Jörg Pawelke; Marek Moszynski; Wolfgang Enghardt

2004-01-01

78

Absolyutnaya spektral'naya chuvstvitel'nost' fotodiodnykh lineek v rentgenovskom diapazone 7-20 kehV. (Absolute spectral sensitivity of photodiode arrays in the X-ray energy range 7-20 keV).  

National Technical Information Service (NTIS)

The results of the investigation of absolute spectral sensitivity of linear photodiode arrays (the kind LF1024-25/2) as X-ray one-coordinate detectors in the energy range from 7 to 20 keV are presented. The measurements have been carried out with the use ...

I. P. Dolbnya S. G. Kurylo

1991-01-01

79

The FPGA Pixel Array Detector  

NASA Astrophysics Data System (ADS)

A proposed design for a reconfigurable x-ray Pixel Array Detector (PAD) is described. It operates by integrating a high-end commercial field programmable gate array (FPGA) into a 3-layer device along with a high-resistivity diode detection layer and a custom, application-specific integrated circuit (ASIC) layer. The ASIC layer contains an energy-discriminating photon-counting front end with photon hits streamed directly to the FPGA via a massively parallel, high-speed data connection. FPGA resources can be allocated to perform user defined tasks on the pixel data streams, including the implementation of a direct time autocorrelation function (ACF) with time resolution down to 100 ns. Using the FPGA at the front end to calculate the ACF reduces the required data transfer rate by several orders of magnitude when compared to a fast framing detector. The FPGA-ASIC high-speed interface, as well as the in-FPGA implementation of a real-time ACF for x-ray photon correlation spectroscopy experiments has been designed and simulated. A 16×16 pixel prototype of the ASIC has been fabricated and is being tested.

Hromalik, Marianne S.; Green, Katherine S.; Philipp, Hugh T.; Tate, Mark W.; Gruner, Sol M.

2013-02-01

80

Vacuum photodiode detectors for soft x-ray ITER plasma tomography  

NASA Astrophysics Data System (ADS)

A special type of vacuum photodiode detector (VPD) for x-ray tomography of (ITER) plasma is described. Laboratory experiments demonstrate that VPD has high sensitivity to thermal x-rays and low sensitivity to hard gamma rays and neutrons. It was shown that in ITER environment the signal due to thermal x-rays will surpass the background signal by more than a factor of 100.

Gott, Yu. V.; Stepanenko, M. M.

2005-07-01

81

Recent developments in the avalanche photodiode x-ray detector for timing and fast counting measurements  

Microsoft Academic Search

An avalanche photodiode (APD) detector using a new silicon device has been developed for x-ray timing measurements. The device, Model No. S5343 (Hamamatsu Photonics), has an excellent time resolution of 0.10 ns and has only a short tail, or a full width of 1.41 ns at 10?5 maximum, in the response function for the time spectrum. Measurements of the purity

Shunji Kishimoto

1995-01-01

82

Gamma-ray imaging detectors based on silicon drift detectors arrays coupled to a single scintillator  

NASA Astrophysics Data System (ADS)

Arrays of Silicon Drift Detectors (SDDs) coupled to a single scintillator, according to the Anger Camera scheme, can be successfully employed in gamma-ray imaging. The low value of output capacitance of a SDD allows to reach a lower electronics noise with respect to conventional silicon photodiodes used in scintillation detection. A small prototype of gamma camera with sub-millimeter resolution has been realized by using a monolithic array of small SDDs (5mm2 each unit) with on-chip JFET. For the realization of gamma cameras of larger areas based on single units assembled in array, SDDs of 30mm2 of area with external JFET have been also experimented.

Fiorini, C.; Longoni, A.

2003-01-01

83

The surface detector array of the Telescope Array experiment  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA) experiment, located in the western desert of Utah, USA, is designed for the observation of extensive air showers from extremely high energy cosmic rays. The experiment has a surface detector array surrounded by three fluorescence detectors to enable simultaneous detection of shower particles at ground level and fluorescence photons along the shower track. The TA surface detectors and fluorescence detectors started full hybrid observation in March, 2008. In this article we describe the design and technical features of the TA surface detector.

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Gorbunov, D.; 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.; 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.; Myers, I.; Minamino, M.; Miyata, K.; Miyauchi, H.; Murano, Y.; 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.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Wood, M.; Yamakawa, Y.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2012-10-01

84

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

85

Determination of bixin and norbixin in meat using liquid chromatography and photodiode array detection.  

PubMed

The development of an analytical method that enables routine analysis of annatto dye, specifically bixin and norbixin, in meat tissue is described. Liquid-solid extraction was carried out using acetonitrile. Analysis was by HPLC with photodiode array detection using two fixed wavelengths (458 and 486 nm). The possibilities of ion trap mass spectrometry (MS) were also assessed. Method performance characteristics, according to Commission Decision 2002/657/EC, were determined, with recoveries between 99 and 102% and calibration curves being linear in the 0.5-10 mg kg(-1) range. The limit of quantification was 0.5 mg kg(-1). PMID:19680866

Noppe, H; Abuin Martinez, S; Verheyden, K; Van Loco, J; Companyo Beltran, R; De Brabander, H F

2009-01-01

86

Analysis of phenolic compounds in spruce needle extracts using an UV-VIS-diode array detector  

Microsoft Academic Search

High-performance liquid chromatography (HPLC) coupled with ultraviolet-visible spectroscopy, using a photodiode-array detector, was applied to the investigation of plant extracts for polyphenolic compounds. Simultaneous detection at different wavelengths and measurement of the UV spectrum of each separated compound during the elution allows an easy and rapid identification of the derivatives of benzoic acid, o-coumaric acid, p-hydroxyacetophenone, stilbenes and flavonoide compounds

H. G. Kicinski; A. Kettrup

1987-01-01

87

Development of the YSU miniball detector array  

NASA Astrophysics Data System (ADS)

At present, studies of x-ray driven gamma emission are constrained by the extremely small size of available targets. Typical targets of ^178Hf^m2 contain only 10^13 - 10^15 isomers with various amounts of contaminant radioisotopes. In order to apply a more sensitive experimental approach to the search for driven gamma emission from such targets, the YSU miniball detector array has been constructed. This array utilizes similar principles to those employed at large many-detector arrays to capture multiple gamma-ray cascades emitted in spontaneous and driven events. The experimental approach, design and testing of the miniball array will be discussed.

Propri, Ron; Burnett, Jason; Drummond, Tom; Lepak, Joel; Smith, David; Carroll, James; Karamian, Sarkis; Adam, Jindrich; Stedile, Frank; Agee, F. J.

2002-04-01

88

Low-Cost, Precision, Self-Alignment Technique for Coupling Laser and Photodiode Arrays to Polymer Waveguide Arrays on Multilayer PCBs  

Microsoft Academic Search

The first, to our knowledge, passive, precision, self-alignment technique for direct coupling of vertical cavity surface emitting laser (VCSEL) and photodiode (PD) arrays to an array of polymer buried channel waveguides on a rigid printed circuit board (PCB) is reported. It gives insertion losses as good as the best achieved previously, to within experimental measurement accuracy, but without the need

Ioannis Papakonstantinou; David R. Selviah; Richard C. A. Pitwon; Dave Milward

2008-01-01

89

Modeling an array of encapsulated germanium detectors  

NASA Astrophysics Data System (ADS)

A probability model has been presented for understanding the operation of an array of encapsulated germanium detectors generally known as composite detector. The addback mode of operation of a composite detector has been described considering the absorption and scattering of ?-rays. Considering up to triple detector hit events, we have obtained expressions for peak-to-total and peak-to-background ratios of the cluster detector, which consists of seven hexagonal closely packed encapsulated HPGe detectors. Results have been obtained for the miniball detectors comprising of three and four seven hexagonal closely packed encapsulated HPGe detectors. The formalism has been extended to the SPI spectrometer which is a telescope of the INTEGRAL satellite and consists of nineteen hexagonal closely packed encapsulated HPGe detectors. This spectrometer comprises of twelve detector modules surrounding the cluster detector. For comparison, we have considered a spectrometer comprising of nine detector modules surrounding the three detector configuration of miniball detector. In the present formalism, the operation of these sophisticated detectors could be described in terms of six probability amplitudes only. Using experimental data on relative efficiency and fold distribution of cluster detector as input, the fold distribution and the peak-to-total, peak-to-background ratios have been calculated for the SPI spectrometer and other composite detectors at 1332 keV. Remarkable agreement between experimental data and results from the present formalism has been observed for the SPI spectrometer.

Kshetri, R.

2012-04-01

90

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

91

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

92

Type-II InAs/GaSb photodiodes and focal plane arrays aimed at high operating temperatures  

NASA Astrophysics Data System (ADS)

Recent efforts to improve the performance of type II InAs/GaSb superlattice photodiodes and focal plane arrays (FPA) have been reviewed. The theoretical bandstructure models have been discussed first. A review of recent developments in growth and characterization techniques is given. The efforts to improve the performance of MWIR photodiodes and focal plane arrays (FPAs) have been reviewed and the latest results have been reported. It is shown that these improvements has resulted in background limited performance (BLIP) of single element photodiodes up to 180 K. FPA shows a constant noise equivalent temperature difference (NEDT) of 11 mK up to 120 K and it shows human body imaging up to 170 K.

Razeghi, M.; Abdollahi Pour, S.; Huang, E. K.; Chen, G.; Haddadi, A.; Nguyen, B. M.

2011-09-01

93

Astronomical polarimeter with 2-D detector arrays  

Microsoft Academic Search

It is shown how fast (50-100 kHz) piezoelastic modulation of the full Stokes vector can be used in combination with large CCD-type detector arrays with long integration times. The technique is to use an optical demodulation system (replacing the lockin amplifiers in corresponding single-channel detector systems). This allows the CCD detectors to be used with integration times and readout rates

J. O. Stenflo; Hanspeter Povel

1985-01-01

94

Quantum state tomography with array detectors.  

PubMed

I propose a method for measuring the quantum state of an optical field that occupies a mode having a complicated spatial structure. The technique uses array detectors and a single, plane-wave local oscillator beam. The advantage of using array detectors is that the local oscillator is not mode matched to the field being measured, yet the deleterious effects of this mismatch on the effective detection efficiency are greatly reduced compared to using single detectors. Indeed, when the spatial mode of the signal field is describable by a real function, the effective mode-matching efficiency is unity. PMID:10991045

Beck, M

2000-06-19

95

Adaptive calibration of imaging array detectors.  

PubMed

We present two methods for nonuniformity correlation of imaging array detectors based on neural networks; both exploit image properties to supply lack of calibrations and maximize the entropy of the output. The first method uses a self-organizing net that produces a linear correction of the raw data with coefficients that adapt continuously. The second method employs a kind of contrast equalization curve to match pixel distributions. Our work originates from silicon detectors, but the treatment is general enough to be applicable to many kinds of array detectors like those used in infrared imaging or in high-energy physics. PMID:10423496

Budinich, M; Frison, R

1999-08-15

96

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

SciTech Connect

Two large-area, low-noise, high-speed fluorescence detectors have been built. One detector consists of a photodiode with an area of 28 mmx28 mm and a low-noise transimpedance amplifier. This detector has a input light-equivalent spectral noise density of less than 3 pW/{radical}(Hz), can recover from a large scattered light pulse within 10 {mu}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 0.08 pW/{radical}(Hz), also can recover from a large scattered light pulse within 10 {mu}s, and has a bandwidth of 1 MHz.

Bickman, S.; DeMille, D. [Physics Department, Yale University, P.O. Box 208120, SPL 23, New Haven, Connecticut 06520 (United States)

2005-11-15

97

The LSO\\/APD array as a possible detector for in-beam PET in hadron therapy  

Microsoft Academic Search

We have studied the performance of finger-like LSO:Ce (LSO) crystals coupled one by one to pixels of avalanche photodiode detector (APD) arrays during their operation in coincidence at 12C ion beams of parameters being typical for tumor irradiations. In a first step of these experiments the parameters of the detectors and the signal processing setup have been characterized off-beam, i.e.,

M. Kapusta; P. Crespo; D. Wolski; K. Heidel; L. Heinrich; J. Hutsch; J. Pawelke; M. Sobiella; A. Trzcinska; M. Moszynski; W. Enghardt

2004-01-01

98

Application of tomographic imaging to photodiode arrays in large helical device  

SciTech Connect

Two 20-channel absolute x-ray ultraviolet photodiode (AXUVD) cameras are being used on the large helical device for measuring the two-dimensional radiation distribution. The local radiation emissivity is obtained by inverting the measured brightnesses with linear (Tikhonov-Phillips) or nonlinear (maximum entropy) regularization methods. The most important features of these improved methods are the capability of reconstructing radiation distributions without any symmetry assumptions, built-in smoothing, and useful reconstructions with relatively few detector channels. Together with improvements in the analysis method, the current AXUVD system makes it possible to obtain radiation emissivity images of various localized radiative phenomena, such as radiation collapse or transport of impurities injected into the plasma.

Liu, Y.; Tamura, N.; Peterson, B. J.; Iwama, N.; LHD Experimental Group [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Daido Institute of Technology, Nagkoya 457-8530 (Japan); National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

2006-10-15

99

Prospects of CsI(Tl)-photodiode detectors for low-level spectroscopy  

NASA Astrophysics Data System (ADS)

A detailed study of the potential of CsI(Tl)-photodiode detectors for applications in low-level spectroscopy was carried out. The energy resolution of small crystals (few cm3) for ?-rays in the MeV range can be parametrized as ?E(FWHM)/E = 5% × E[MeV]-0.69. In kg size detectors, where resolution is limited by electronic noise, the use of new large-area low-capacitance pin Si photodiodes led to a significantly improved energy precision of ?E (FWHM) = 150 keV, nearly independent of energy. Unfavourable light collection geometries, like in large-acceptance well detectors, do not substantially degrade the energy measurement. Scintillation light yields vary slowly with temperature and time so excellent long-term stability can be expected. For the first time a systematic investigation of inherent crystal radioactivity was possible due to the improved energy resolution obtained with large crystals. Six ?-active radionuclides of the Th-decay-chain were identified. The isotopes are in equilibrium with each other but not in secular equilibrium with 232Th. The total ?-activity varies from crystal to crystal between 2.4 and 5.5 decays/h cm3) corresponding to 228Th concentrations of 1.1-2.5×10-18 g/g. Activity from 238U-chain isotopes is not sent at a level two orders of magnitude below the Th-activity. Prospects are discussed for further improved energy resolution and for applications in low-level spectroscopy, specifically for a search for 100Mo double beta decay.

Kilgus, U.; Kotthaus, R.; Lange, E.

1990-12-01

100

Method for the quantification of the blue-green pigment “marennine” synthesized by the marine diatom Haslea ostrearia (Gaillon\\/Bory) Simonsen using HPLC gel-filtration and photodiode-array detection  

Microsoft Academic Search

This paper describes a new approach for quantifying marennine, a blue-green pigment synthesized by the marine diatom Haslea ostrearia, which is known to be responsible for the greening of cultured oysters in French coastal areas. The method uses gel-filtration\\u000a HPLC interfaced with a photodiode-array detector (PDA). Under the chromatographic conditions applied, the peak of marennine\\u000a is identified on the dextran

Jean-Bernard Pouvreau; Michèle Morançais; Joël Fleurence; Pierre Pondaven

2007-01-01

101

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

102

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

SciTech Connect

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 {gamma}-rays from a {sup 137}Cs source was obtained with a 9 mm in diameter by 9 mm high CsI(Tl) scintillator coupled to an LAAPD. Measuring the number of primary electron-hole pairs produced in the LAAPD and photoelectrons in the photomultiplier, as well as the noise contribution of the LAAPD, allowed a quantitative discussion of the results. The energy resolutions measured with LAAPDs are comparable to, or significantly better (at certain emission wavelengths) than, those obtained with the photomultiplier. At energies above 100 keV the energy resolution measured with the majority of crystals and the LAAPD was weakly affected by the photodiode noise contribution. The advantages and limitations of LAAPDs in energy spectrometry with scintillation detectors are also discussed.

Moszynski, M.; Wolski, D. [Soltan Inst. for Nuclear Studies, Swierk-Otwock (Poland); Kapusta, M. [Soltan Inst. for Nuclear Studies, Swierk-Otwock (Poland)]|[Univ. of Warsaw (Poland). Inst. of Experimental Physics; Szawlowski, M. [Advanced Photonix, Inc., Camarillo, CA (United States); Klamra, W. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Physics

1998-06-01

103

Megapixel detector arrays: visible to 28 ?m  

NASA Astrophysics Data System (ADS)

Large infrared detector arrays are now available that meet the demanding requirements of the astronomy and civil space communities. This paper describes arrays with more than one million detector elements developed by Raytheon Vision Systems for these low-background applications. These detector arrays have 1024 x 1024 and 2048 x 2048 formats with element spacing ranging from 20 to 27 ?m. Arrays of this size have been demonstrated with a variety of deteector materials: Si PIN, HgCdTe, InSb, and Si:As IBC. The performance of each of these materials on arrays with more than one million detector elements is discussed. All of these detector materials have demonstrated low noise and dark current, high quantum efficiency, and excellent uniformity. All can meet the high performance requirements for low-background within the limits of their respective spectral and operating temperature ranges. Features of the readout integrated circuits that mate to these detector arrays are also discussed. Companion papers in these SPIE proceedings that discuss several of these arrays in more detail are: 1. "Large-format 0.85 and 2.5 ?m HgCdTe detctor arrays for low-background applications", P.J. Love, A. W. Hoffman, D. L. Gulbransen, K. J. Ando, M. P. Murray, N. J. Therrien 2. "James Webb Space Telescope characaterization of flight candidate NIR InSb array", C. W. McMurtry, W. J. Forrest, J. L. Pipher, A. C. Moore 3. "Orion II: the second-generation readout multiplexer for largest infrared hybrid focal plane", K. M. Merrill, A. M. Fowler, W. Ball, A. Henden, F. J. Vrba, C. McCreight 4. "Interpixel capacitance in nondestructive focal plane arrays" A. C. Moore 5. "Radiation environment performance of JWST prototype FPAs", M. E. McKelvey, K. A. Enico, R. E. McMurray Jr., R. A. Reed, C. R. McCreight 6. "Independent testing of JWST detector prototypes," D. F. Figer, B. Rauscher, M. W. Regan, J. Balleza, L. Bergeron, E. Morse, H. S. Stockman.

Hoffman, Alan W.; Love, Peter J.; Rosbeck, Joseph P.

2004-01-01

104

Measurement of ²²²Rn diffusion through sandy soil with solar cells photodiodes as the detector.  

PubMed

An experimental system was developed to study the diffusion rate of radon (²²²Rn) gas through porous media as a function of soil porosity/grain size and soil water content. Columns with different grain sizes, soil water content and soil depths were used. The system used solar cells photodiodes as alpha (?) detectors. This new detector is highly efficient and low cost compared to other known detectors. Soil water content was found to be the most dominant factor affecting the ²²²Rn diffusion rate. A maximum diffusion rate value of (6.5 ± 0.07) × 10?? m²/s was found in dry conditions. The minimum diffusion value of less than (3.9 ± 0.14) × 10?? m²/s was found in 2% soil water content. The experimental results were compared with theoretical calculations done with the "GREEN equation". Two discrepancies were observed: the time to equilibrium state in the measurements was longer compare to the calculated values and the ? count rates were lower in the experiment compared with the theoretical calculations. These results can be explained by the differences in the system geometry. PMID:22230015

Shitrit, Y; Dody, A; Alfassi, Z B; Berant, Z

2011-11-10

105

Initial characterization of a BGO-photodiode detector for high resolution positron emission tomography  

SciTech Connect

Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon photodiodes (SPDs) for crystal identification, and coupled in groups to phototubes (PMTs) for coincidence timing. A 3 mm x 3 mm x 3 mm BGO crystal coupled only to an SPD can achieve a 511 keV photopeak resolution of 8.7% FWHM at -150/sup 0/C, using a pulse peaking time of 10 ..mu..s. When two 3 mm x 3 mm x 15 mm BGO crystals are coupled individually to SPDs and also coupled to a common 14 mm diam PMT, the SPDs detect the 511 keV photopeak with a resolution of 30% FWHM at -76/sup 0/C. In coincidence with an opposing 3 mm wide BGO crystal, the SPDs are able to identify the crystal of interaction with good signal-to-noise ratio, and the detector pair resolution is 2 mm FWHM. 32 references, 7 figures, 3 tables.

Derenzo, S.E.

1983-11-01

106

A comparison of avalanche photodiode and photomultiplier tube detectors for flow cytometry  

NASA Astrophysics Data System (ADS)

Commercial flow cytometers use photomultiplier tubes (PMTs) for fluorescence detection. These detectors have high linear gain and broad dynamic range, but have limited sensitivity in the red and near infrared spectral regions. We present a comparison of avalanche photodiodes (APDs) and PMTs as detectors in flow cytometry instruments, and demonstrate improved sensitivity and resolution in the red and near infrared spectral regions using the APD. The relative performance of the PMT and APD were evaluated by simultaneously measuring the mean fluorescence intensity and coefficient of variation for emission from light emitting diode pulses, flow cytometry test beads, and fluorescently labeled cells. The relative signal to noise performance of the APD and PMT was evaluated over the 500 nm to 1050 nm wavelength range using pulsed light emitting diode light sources. While APDs have higher quantum efficiency but lower internal gain than PMTs, with appropriate external amplification the APD has signal to noise response that is comparable to PMTs in the 500 nm to 650 nm range and improved response in the 650 nm to 850 nm range The data demonstrates that the APD had performance comparable to the PMT in the spectral region between 500 to 650 nm and improved performance in the range of 650 to 1000 nm, where the PMT performance is quite poor. CD4 positive lymphocyte populations were easily identified in normal human blood both by APD and PMT using phycoerythrin labeled antibodies. In contrast, only the APD detector could resolve CD4 positive populations using 800 nm Quantum dot labeled antibodies.

Lawrence, William G.; Varadi, Gyula; Entine, Gerald; Podniesinski, Edward; Wallace, Paul K.

2008-03-01

107

Classification performance of carbon black-polymer composite vapor detector arrays as a function of array size and detector composition  

Microsoft Academic Search

The vapor classification performance of arrays of conducting polymer composite vapor detectors has been evaluated as a function of the number and type of detectors in an array. Quantitative performance comparisons were facilitated by challenging a collection of detector arrays with vapor discrimination tasks that were sufficiently difficult that at least some of the arrays did not exhibit perfect classification

Michael C Burl; Brian C Sisk; Thomas P Vaid; Nathan S Lewis

2002-01-01

108

Faraday Cup Detector Array with Electronic Interface  

NASA Astrophysics Data System (ADS)

A position sensitive Faraday cup detector array [FCDA] for ion beam detection has been developed. The FCDA is combined with an electronic multiplexing unit that allows collecting and integrating the charge deposited in the array and simultaneously reading out the same. The interface allows a duty cycle of > 98% for the position sensitive read-out, thus monitoring the entire array simultaneously. The multiplexing is achieved by collecting the charge with large number of small, and electronically de-coupled Faraday cups. The device measures absolute ion currents, has a wide dynamic range from 0.2 picoA to 2 microA, and a cross talk of less than 750:1. Read-out speeds ranging from 37 Hz to 117 kHz have been demonstrated. The low cross talk of the FCDA originates from an effective electronic de-coupling of the cups and a gray-code driven MUX-cascade as interface. The integration of the interface with the detector array on a printed circuit board allows further, reducing the number of feedthroughs that are necessary to monitor the array to six. Detector pitch sizes from 150 mm to 2.1mm haven been realized. A linear system composed of 256 elements and a square arrangement with 64 elements will be discussed.

Scheidemann, Adi A.; Schumacher, Frank. J.; Darling, Robert B.; Isakharov, Arthur; Jones, Patrick

2000-03-01

109

Centroid tracking with area array detectors  

NASA Astrophysics Data System (ADS)

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.

1986-06-01

110

Signal processing for an infrared array detector  

SciTech Connect

A broadband detection scheme for a time-resolved infrared absorption spectrometer, based on a multielement mercury-cadmium-telluride (MCT) array, has been successfully implemented. The spectrometer achieves a resolution on the 10-ns time scale despite the much larger time constant characteristic of the MCT elements. Our signal-collection circuitry takes advantage of the slow decay by integrating the detector response to pulsed IR radiation. The dynamic range is 100--1 and the resultant noise level is near the detector limit. Data acquisition for the 120 elements is fast enough to allow scan rates of 30--40 Hz. The completed electronics are sufficiently compact to be situated local to the array detector, and the design is relatively inexpensive to construct using commonly found electronic components.

Young, M.A.; Smith, G.E.; Pimentel, G.C. (Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (US))

1989-09-01

111

Characterization of the principal colouring components of annatto using high performance liquid chromatography with photodiode-array detection.  

PubMed

The principal colouring components of the natural food colouring material annatto, the 9'-cis- and all-trans- isomers of bixin and norbixin, have been prepared in pure form. A reverse-phase HPLC method utilizing photodiode-array detection has been developed to enable their chromatographic and spectroscopic characterization. One minor component, a di-cis-isomer of norbixin has also been identified and characterized. PMID:7926164

Scotter, M J; Thorpe, S A; Reynolds, S L; Wilson, L A; Strutt, P R

112

Terahertz detectors and focal plane arrays  

NASA Astrophysics Data System (ADS)

Terahertz (THz) technology is one of emerging technologies that will change our life. A lot of attractive applications in security, medicine, biology, astronomy, and non-destructive materials testing have been demonstrated already. However, the realization of THz emitters and receivers is a challenge because the frequencies are too high for conventional electronics and the photon energies are too small for classical optics. As a result, THz radiation is resistant to the techniques commonly employed in these well established neighbouring bands. In the paper, issues associated with the development and exploitation of THz radiation detectors and focal plane arrays are discussed. Historical impressive progress in THz detector sensitivity in a period of more than half century is analyzed. More attention is put on the basic physical phenomena and the recent progress in both direct and heterodyne detectors. After short description of general classification of THz detectors, more details concern Schottky barrier diodes, pair braking detectors, hot electron mixers and field-effect transistor detectors, where links between THz devices and modern technologies such as micromachining are underlined. Also, the operational conditions of THz detectors and their upper performance limits are reviewed. Finally, recent advances in novel nanoelectronic materials and technologies are described. It is expected that applications of nanoscale materials and devices will open the door for further performance improvement in THz detectors.

Rogalski, A.; Sizov, F.

2011-09-01

113

Bonded wafer substrates for integrated detector arrays  

SciTech Connect

Bonded wafer substrates have been made which are optimized for integrating high energy particle detector arrays with their readout electronics. The detectors are processed in the handle wafer, which is a 300 [mu]m thick, high resistivity, <111> crystal orientation silicon wafer. This wafer is bonded to a primary wafer using a low temperature process that does not affect the detector material. The support electronics are processed in the remnant of the primary wafer, which is a submicron thick <100> crystal orientation silicon film formed by a bond-and-etchback procedure. These two device materials are isolated from each other by a radiation hardened dielectric film. The integrated process is based on a low temperature, radiation hardened VLSI CMOS process which is also shown not to seriously affect the detector material.

Wang, J.J.; King, E.E.; Leonov, P.; Huang, D.H. (Advanced Research and Applications Corp., Sunnyvale, CA (United States)); Thompson, P.; Godbey, D. (Naval Research Lab., Washington, DC (United States))

1993-10-01

114

Thick, segmented CdWO{sub 4}-photodiode detector for cone beam megavoltage CT: A Monte Carlo study of system design parameters  

SciTech Connect

Megavoltage (MV) imaging detectors have been the focus of research by many groups in recent years. We have been working with segmented CdWO{sub 4} crystals in contact with photodiodes in our lab. The present study uses both x-ray and optical photon transport Monte Carlo simulations to analyze the effects of scintillation crystal height, septa material, beam divergence, and beam spectrum on the modulation transfer function, MTF(f) and zero frequency detective quantum efficiency, DQE(0), of a theoretical area detector. The theoretical detector is comprised of tall, segmented CdWO{sub 4} crystals and two dimensional photodiode arrays with a pitch of 1 mm and a fill factor of 72%. Increasing the crystal height above 10 mm does not result in an improvement in the DQE(0) if the reflection coefficient of the septa is less than 0.8. For a reflection coefficient of 0.975 for the septa, there is a continual gain in the DQE(0) up to 30 mm tall crystals. Similar calculations show that employing a 3.5 MV beam without a flattening filter increases the DQE(0) for 20 mm tall crystals by 9% compared to a typical 6 MV beam with a flattening filter. The severe degradations due to beam divergence on MTF(f) are quantified and suggest the use of focused detectors in MV imaging. It is found that when the effect of optical photons is considered, the presence of divergence can appear as a shift in the location of the input signal as well as loss of spatial resolution.

Monajemi, T. T.; Fallone, B. G.; Rathee, S. [Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Departments of Oncology and Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

2006-12-15

115

Why compton-suppressed germanium detector arrays?  

SciTech Connect

Nuclear spectroscopic studies have provided a strong incentive to obtain {gamma}-ray detectors with increasingly better energy resolution, higher full-energy peak efficiencies, and greater sensitivity or resolving power. A major step was the introduction of Ge detectors in the early 60`s. But because of the low atomic number of Ge they have a poor response function; a majority of interacting gamma rays of moderate energy Compton scatter out of the detector leaving a large low-energy background. The remedy was to add a Compton-suppression shield made of NaI around the Ge crystal, and if interactions occurred simultaneously in the NaI scintillator and in the Ge detector to veto that event. Efficiencies also increased greatly when an English-Danish collaboration assembled five Ge detectors, each with a NaI suppressor, into the first array at the end of 1980. Obviously, a system of five such detectors gave much better statistics than the usual two bare detectors used for obtaining coincidence data (by a factor of 10). A few years later, another major improvement came with replacement of the NaI suppressors with shields made of the much denser bismuth germanate (BGO) as scintillator, as these could be thinner leading to arrays with of order 20 detectors. Use of such a large number of detectors led to the realization that for cascades of coincident gamma rays, as in going down a band, the improvement in the peak/background ratio observed and already appreciated in going from singles spectra to gated (double-) coincidence spectra continued when doubly-gated triple-coincidence data were compared for the first time to singly-gated double-coincidence ones. The higher-gated spectra were much cleaner and more selective, though with poorer statistics, and the advantages of higher folds and efficiencies led to the proposals for the larger 4{pi} arrays of today, Eurogam and GASP in Europe and Gammasphere in the U.S.

Diamond, R.M. [Lawrence Berkeley Laboratory, CA (United States)

1993-10-01

116

The SORDS trimodal imager detector arrays  

NASA Astrophysics Data System (ADS)

The Raytheon Trimodal Imager (TMI) uses coded aperture and Compton imaging technologies as well as the nonimaging shadow technology to locate an SNM or radiological threat in the presence of background. The heart of the TMI is two arrays of NaI crystals. The front array serves as both a coded aperture and the first scatterer for Compton imaging. It is made of 35 5x5x2" crystals with specially designed low profile PMTs. The back array is made of 30 2.5x3x24" position-sensitive crystals which are read out at both ends. These crystals are specially treated to provide the required position resolution at the best possible energy resolution. Both arrays of detectors are supported by aluminum superstructures. These have been efficiently designed to allow a wide field of view and to provide adequate support to the crystals to permit use of the TMI as a vehicle-mounted, field-deployable system. Each PMT has a locally mounted high-voltage supply that is remotely controlled. Each detector is connected to a dedicated FPGA which performs automated gain alignment and energy calibration, event timing and diagnostic health checking. Data are streamed, eventby- event, from each of the 65 detector FPGAs to one master FPGA. The master FPGA acts both as a synchronization clock, and as an event sorting unit. Event sorting involves stamping events as singles or as coincidences, based on the approximately instantaneous detector hit pattern. Coincidence determination by the master FPGA provides a pre-sorting for the events that will ultimately be used in the Compton imaging and coded aperture imaging algorithms. All data acquisition electronics have been custom designed for the TMI.

Wakeford, Daniel; Andrews, H. R.; Clifford, E. T. H.; Li, Liqian; Bray, Nick; Locklin, Darren; Hynes, Michael V.; Toolin, Maurice; Harris, Bernard; McElroy, John; Wallace, Mark; Lanza, Richard

2009-05-01

117

Large Area Avalanche Photodiode Detectors for a Small Etendue Thomson Scattering Diagnostic  

NASA Astrophysics Data System (ADS)

The RFP requires a close conducting shell and small field errors. For this reason diagnostic ports are kept small, leading to a small etendue (0.19 mm^2-str) for TS light collection optics. In addition, the MST RFP operates at a low plasma density of ~ 10^13cm-3. Thomson scattered light levels are therefore lower than those found typically in tokamaks. Recently the MST TS system was upgraded to overcome the low signal level associated with its operational environment and to produce accurate single shot temperature measurements. Signal to noise enhancement was accomplished primarily through the use of 11 large area avalanche photodiode detectors with high quantum efficiency (90%) and low noise. Spectral coverage was increased from 50 nm to 100 nm. Single channel signal to noise improvement of 5X is expected, reducing the uncertainty in the electron temperature measurements from ~ 40% to ~ 10%. Preliminary results are reported. This work was supported by the U.S. D.O.E.

Biewer, T. M.; Stoneking, M. R.; den Hartog, D. J.

1996-11-01

118

Construction of a fast, inexpensive rapid-scanning diode-array detector and spectrometer.  

PubMed

A 512-element diode-array spectroscopic detection system capable of acquiring multiple spectra at a rate of 5 ms per spectrum with an effective scan rate of 102.9 kHz has been constructed. Spectra with fewer diode elements can also be acquired at scan rates up to 128 kHz. The detector utilizes a Hamamatsu silicon photodiode-array sensor that is interfaced to Hamamatsu driver/amplifier and clock generator boards and a DRA laboratories 12-bit 160-kHz analog-to-digital converter. These are standard, commercially available devices which cost approximately $3500. The system is interfaced to and controlled by an IBM XT microcomputer. Detailed descriptions of the home-built detector housing and control/interface circuitry are presented and its application to the study of the reaction of horseradish peroxidase with hydrogen peroxide is demonstrated. PMID:2285140

Carter, T P; Baek, H K; Bonninghausen, L; Morris, R J; van Wart, H E

1990-10-01

119

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

120

Absorbance measurements with light-emitting diodes as sources: Silicon photodiodes or light-emitting diodes as detectors?  

PubMed

Light-emitting diodes may also serve as light detectors, and the combination of two of these devices, one serving as light source, the other for detection, has been reported repeatedly for use in analytical photometry. A comparative study of the performance of light-emitting diodes in this role and that of a standard photodiode is reported herein. The spectral sensitivities of the light-emitting diodes were found to be as narrow as their emission bands, but shifted to shorter wavelengths, so that the spectral overlaps between emission and sensitivity of the same devices are very limited. The photocurrents of the light-emitting diodes were found to be about ten times lower than those of the photodiode. In the discharge mode (the time for discharge of the p/n-junction by the photocurrent is measured) as well as the photovoltaic mode, both of which had previously been reported for light-emitting diodes used as detectors in photometric devices, the performance of a light-emitting diode was on a level that is adequate for many analytical purposes, but the photodiode generally gave better precision and the signals showed faster settling times. PMID:24148518

Anh Bui, Duy; Hauser, Peter C

2013-08-23

121

Microphone array based novel infant deafness detector.  

PubMed

This work focuses on an infant deafness detector unit, using the concept of microphone array. This instrument is based on the principle of evoked acoustic emissions (OAEs). The key feature of the microphone array is its ability to increase signal-to-noise ratio (SNR) and reproducibility of the OAE responses. These further significantly contribute to improve the sensitivity and specificity of the overall system. Low level sound pressure values are recorded by the sensitive microphones in microphone array unit and processed using TI's DSP6416. The sound stimulus transmitted to human ear is generated and controlled by the 6416 DSP (Digital signal processor). Hardware circuit details and the algorithm used in signal processing are discussed in this paper. Standard averaging technique is used in the implemented algorithm. The final result speaks about the hearing capacity of a patient. The proof that the usage of microphone arrays leads to better SNR values than using a single microphone in an OAE probe, is successfully carried out in this work. PMID:21097204

Agnihotri, Chinmayee; Thiyagarajan, S; Kalyansundar, Archana

2010-01-01

122

Optical observations of terrestrial lightning by the FORTE satellite photodiode detector  

NASA Astrophysics Data System (ADS)

We review data from observations of terrestrial lightning obtained by the FORTE satellite between September 1997 and January 2000. A silicon photodiode detector (PDD) records the intensity-time history of transient optical events occurring within its 80° circular field of view. This field of view corresponds to a circle on the Earth's surface having an approximate diameter of 1200 km. We describe the instrument, present examples of the data, explain how the data are screened for false triggers, and review, within the context of previous measurements, the general statistics of peak irradiance, pulse width, and energy associated with the data. We compare the FORTE data with National Lightning Detection Network (NLDN) reported cloud-to-ground (CG) strokes and find that the PDD detection efficiency for these CG strokes is ˜6%. Moreover, we infer that FORTE preferentially detects the in-cloud portion of optical lightning signals. Events having inferred peak powers between 108 and 1012 W and optical energy outputs between 103 and 109 J are observed. From a population of nearly 700,000 events we find that the median peak power and median detected optical energy at the source are estimated to be ˜1×109 W and 4.5×105 J, respectively. These values of source peak power and energy are comparable to previous space-based measurements and consistent with aircraft-based and ground-based measurements. The observed median effective pulse width is about 590 microseconds. Further, the pulse widths for CG strokes, reported by NLDN, are inversely proportional to pulse peak power.

Kirkland, M. W.; Suszcynsky, D. M.; Guillen, J. L. L.; Green, J. L.

2001-12-01

123

A large-area monolithic array of silicon drift detectors for medical imaging  

NASA Astrophysics Data System (ADS)

Monolithic arrays of silicon drift detectors (SDDs) have been recently proposed to be used with scintillators for high-position-resolution ?-ray imaging applications. Thanks to the low electronics noise due to the small value of the output capacitance, the SDD offers better noise performances with respect to conventional photodiodes of the same geometry. Small monolithic arrays of SDDs have been used as photodetector of the scintillation light in a first prototype of Anger Camera for ?-ray imaging characterized by an intrinsic resolution better than 0.3 mm. In this work, we present a new large-area monolithic array of SDDs. It consists of a single chip composed of 77 single hexagonal units, each one with an active area of 8.7 mm2, for a total active area of the device of 6.7 cm2. It represents the largest monolithic array of SDDs with on-chip JFETs produced up to now for X-ray and ?-ray detection. The results achieved in the experimental characterization of a first prototype of the detector array are presented, both with X and visible photons. The energy resolution measured at 6 keV with the single unit of the array is of 142 eV at -10 °C, while a QE>90% was measured at ?=550 nm.

Fiorini, C.; Gola, A.; Longoni, A.; Zanchi, M.; Restelli, A.; Perotti, F.; Lechner, P.; Soltau, H.; Strüder, L.

2006-11-01

124

Test and evaluation of infrared detectors and arrays; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989  

NASA Astrophysics Data System (ADS)

Papers on the testing and evaluation of IR detectors and arrays are presented, covering topics such as a short wavelength IR test system, pulse height analysis, the use of an expert system for IR detector testing, low-background IR focal plane testing, electron beam testing, high performance silicide Schottky photodiodes, the SDI organization focal plane test program, the absorption cross section of arsenic in silicon, and long wavelength IR hybrids. Other topics include low background radiometric detector measurements, an ultralow background dewar for IR detector characterization studies, a computer assisted mosaic array test station, a configurable detector array test station, automated detector material characterization capabilities, and a test system for mercury cadmium telluride photoconductor arrays. Additional topics include ionization dosimetry measurements inside a dewar for linac electron and californium-252 neutron environments, a radiation test facility using a variable-flux electron beam source, automated visual inspection of IR focal plane arrays, a titanium cryostat for low temperature radiation effects studies, a low dose rate gamma test facility, and the test and evaluation of stability in IR staring focal plane arrays after nonuniformity correction.

Hoke, Forney M.

125

Detector array for measurement of high-frequency fluctuations in visible and near-UV emission from tokamaks  

SciTech Connect

We developed an imaging detector to measure high-frequency fluctuations in visible and near-UV emission from tokamaks. The detector is intended for the study of plasma turbulence, mhd phenomena, and edge-localized modes. Particularly in the first two applications, it will complement existing techniques by providing higher spatial resolution as well as measurement capability in otherwise inaccessible regions of the plasma. The device consists of an optical system, a linear array of 32 photodiodes, and an amplifier for each photodiode. The amplifiers have a transimpedance gain of 10{sup 5}--10{sup 6} and the frequency response is flat to 100 kHz. Experience with this device has shown that optical imaging systems can be easily designed and tailored to a specific measurement because of the small size and close spacing of the individual light-sensitive elements. The device has been successfully tested on TEXT-U in measurements of H{sub {alpha}} fluctuations.

Hurwitz, P.D.; Hall, B.F.; Rowan, W.L. (Fusion Research Center, The University of Texas at Austin, Austin, Texas 78712 (United States))

1992-10-01

126

Detector Arrays for Low-Background Space Infrared Astronomy.  

National Technical Information Service (NTIS)

The status of development and characterization tests of integrated infrared detector array technology for astronomy applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, with hybr...

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

1986-01-01

127

Submicrometre bridge electrode arrays for light emitting polymer diodes and photodiodes  

Microsoft Academic Search

We have used a method of soft lithography, soft imprinting, to fabricate submicrometre structures to be used as light emitting polymer diodes and photodiodes. Using a silicone rubber replica (stamp) of an optical diffraction grating we transferred the grating pattern to an organic resist layer by placing the stamp in conformal contact with the resist. The transferred pattern was subsequently

Tobias Nyberg; Fengling Zhang; Olle Inganäs

2002-01-01

128

Simultaneous determination of seven main alkaloids of Chelidonium majus L. by ultra-performance LC with photodiode-array detection.  

PubMed

A simple and rapid method for the simultaneous determination of seven isoquinoline alkaloids, protopine, chelidonine, coptisine, stylopine, sanguinarine, berberine, and chelerythrine, in Chelidonium majus L. (Ch. majus) samples by ultra-performance LC method with photodiode array detection is described. The baseline separation of these compounds was performed with (A) acetonitrile-(B) ammonium acetate (10 mM, adjusted to pH 3.0 with acetic acid) as the mobile phase using a C18 RP column (2.1x100 mm, 1.7 microm). Optimized conditions resulted in excellent peak shapes. The seven alkaloids were completely separated within 20 min. Good linear behaviors (r > or = 0.9992) over the investigated concentration ranges were observed for all the analytes. Validation proved the repeatability of the method was good and recovery was satisfactory. The validated method was successfully applied for 20 batches of Ch. majus. These results demonstrated that the ultra-performance LC photodiode array method proposed was very useful in the analysis and quality control of Ch. majus. PMID:20183823

Gu, Yue; Qian, Dawei; Duan, Jin-ao; Wang, Zhenzhong; Guo, Jianming; Tang, Yuping; Guo, Sheng

2010-04-01

129

Classification performance of carbon black-polymer composite vapor detector arrays as a function of array size and detector composition  

NASA Astrophysics Data System (ADS)

The vapor classification performance of arrays of conducting polymer composite vapor detectors has been evaluated as a function of the number and type of detectors in an array. Quantitative performance comparisons were facilitated by challenging a collection of detector arrays with vapor discrimination tasks that were sufficiently difficult that at least some of the arrays did not exhibit perfect classification ability for all of the tasks of interest. For nearly all of the discrimination tasks investigated in this work, classification performance either increased or did not significantly decrease as the number of chemically different detectors in the array increased. Any given subset of the full array of detectors, selected because it yielded the best classification performance at a given array size for one particular task, was invariably outperformed by a different subset of detectors, and by the entire array, when used in at least one other vapor discrimination task. Arrays of detectors were nevertheless identified that yielded robust discrimination performance between compositionally close mixtures of 1-propanol and 2-propanol, n-hexane and n-heptane, and meta-xylene and para-xylene, attesting to the excellent analyte classification performance that can be obtained through the use of such semi-selective vapor detector arrays.

Burl, Michael C.; Sisk, Brian C.; Vaid, Thomas P.; Lewis, Nathan S.

2002-08-01

130

Indium antimonide large-format detector arrays  

NASA Astrophysics Data System (ADS)

Large format infrared imaging sensors are required to achieve simultaneously high resolution and wide field of view image data. Infrared sensors are generally required to be cooled from room temperature to cryogenic temperatures in less than 10 min thousands of times during their lifetime. The challenge is to remove mechanical stress, which is due to different materials with different coefficients of expansion, over a very wide temperature range and at the same time, provide a high sensitivity and high resolution image data. These challenges are met by developing a hybrid where the indium antimonide detector elements (pixels) are unconnected islands that essentially float on a silicon substrate and form a near perfect match to the silicon read-out circuit. Since the pixels are unconnected and isolated from each other, the array is reticulated. This paper shows that the front side illuminated and reticulated element indium antimonide focal plane developed at L-3 Cincinnati Electronics are robust, approach background limited sensitivity limit, and provide the resolution expected of the reticulated pixel array.

Davis, Mike; Greiner, Mark

2011-06-01

131

Beam profile shaping for laser radars that use detector arrays  

Microsoft Academic Search

The beam shaper developed shapes the transmit beam of a CO2 laser radar that uses a linear detector array. It consists of a diffraction grating and an anamorphic prism beam compressor, and produces a stretched profile that efficiently and uniformly illuminates the far-field footprint of the detector array. The diffraction grating phase modulates the near field of the laser beam

W. B. Veldkamp; C. J. Kastner

1982-01-01

132

The Impact of Array Detectors on Raman Spectroscopy  

ERIC Educational Resources Information Center

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

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

2007-01-01

133

The Impact of Array Detectors on Raman Spectroscopy  

ERIC Educational Resources Information Center

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

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

2007-01-01

134

A bench-top megavoltage fan-beam CT using CdWO{sub 4}-photodiode detectors. II. Image performance evaluation  

SciTech Connect

Megavoltage computed tomography (MVCT) is a potential imaging tool for positioning and dose delivery verification during image guided radiotherapy. The problem with many MVCT detectors, however, is their low detective quantum efficiency (DQE) which leads to poor low contrast resolution (LCR) and high image noise. This makes separating the tumors from the soft tissue background difficult. This manuscript describes the imaging performance of our bench-top MVCT scanner that uses an 80-element detector array consisting of CdWO{sub 4}-photodiode elements with a DQE of 19% in 6 MV and 26% in Co{sup 60} beams [T. T. Monajemi, S. Steciw, B. G. Fallone, and S. Rathee, 'Modelling scintillator-photodiodes as detectors for megavoltage CT', Med. Phys. 31, 1225-1234 (2004)] at zero frequency. The imaging experiments presented were carried out mainly in a Co{sup 60} teletherapy unit, while the beam hardening characteristics of the system were also presented for a 6 MV beam. During image evaluation, persistent ring artifacts, caused by air gaps at the ends of the eight-element detector blocks, were removed by using a calibration procedure. The measured contrast of a low contrast target with a 20 mm diameter was determined to be independent of dose, between 2.1 and 17 cGy. The measured LCR of a target with a nominal contrast of 2.8% was reduced from 2.3% to 1.2% when the contrast target diameter was reduced from 15 to 5 mm, using 17 cGy for imaging. The signal to noise ratio of this system is shown to be proportional to the square root of dose. Most importantly, a low contrast target with a diameter of 6 mm and a nominal contrast level of 1.5% is resolved with a radiation dose of 2.1 cGy in the Co{sup 60} beam. The spatial resolution in the Co{sup 60} beam is limited to one line pair per centimeter mainly due to the size of the Co{sup 60} source.

Monajemi, T.T.; Tu, D.; Fallone, B.G.; Rathee, S. [Department of Medical Physics, Cross Cancer Institute and Departments of Oncology and Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute and Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

2006-04-15

135

Popcorn noise in linear In0.53Ga0.47As detector arrays  

NASA Astrophysics Data System (ADS)

Popcorn noise, also called burst noise, manifests itself as a random charge fluctuation in linear In(subscript 0.53)Ga(subscript 0.47)As detector arrays. The noise is not present in all the devices; it may affect only 1 or 2% of the photodiodes at a moderately high reverse bias (5 V) but represents a potential performance limitation for the InGaAs photodetector arrays. The random charge fluctuations can be of the order of a few hundred to a million electrons at room temperature and can also be observed at temperatures as low as 200 K. Our studies suggest that dislocations which originate in the InP substrate are the major cause of popcorn noise. This noise can be significantly reduced or completely eliminated by reducing the reverse bias of the photodiodes from 5 V to 2 V or less. Crystal defects seem to cause the popcorn noise when the diode is substantially depleted. A lower reverse bias prevents the depletion width from reaching these defects and thereby prevents the possible generation of popcorn noise.

Joshi, Abhay M.; Olsen, Gregory H.; Ban, Vladimir S.; Mykietyn, E.; Mohr, D. R.

1992-08-01

136

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

Microsoft Academic Search

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

Berthold Büchele; Thomas Simmet

2003-01-01

137

SOLID PHASE EXTRACTION AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHY WITH PHOTODIODE ARRAY DETECTION OF CHEMICAL INDICATORS OF HUMAN FECAL CONTAMINATION IN WATER  

Microsoft Academic Search

Faster and more sensitive analysis of water that is contaminated by human fecal matter is very important for public health. The current microbiological methods to assess water quality do not meet this need. Alternate non-microbial human fecal indicators have been proposed by various researchers. The high performance liquid chromatography (HPLC) analysis with photodiode array detection (PDA) of three human fecal

E. A. Piocos; A. A. de la Cruz

2000-01-01

138

Empirical approach to the description of spectral performance degradation of silicon photodiodes used as particle detectors  

Microsoft Academic Search

The spectral deterioration of Hamamatsu S5821 silicon photodiodes for ion types and energies frequently used in Ion Beam Analysis was investigated. Focused proton beams with energies 430keV and 2MeV were applied to generate radiation damage via an area selective ion implantation in unbiased diodes at room temperature. The variations of spectroscopic features were measured “in situ” by Ion Beam Induced

G. Kalinka; M. Novák; A. Simon; Ž. Pastuovi?; M. Jaksic; Á. Z. Kiss

2009-01-01

139

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

Microsoft Academic Search

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

John Moore Boudry

1996-01-01

140

Radiance temperature scales of KRISS realized by two radiation thermometers using pyroelectric detector and silicon photodiode from 273 K to 2900 K  

NASA Astrophysics Data System (ADS)

The radiance temperature scale of KRISS has been realized from 273 K to 2900 K using two commercially available radiation thermometers. Above 873 K, we calibrate a silicon photodiode-based thermometer (LP4) with 4 spectral bands (650 nm, 750 nm, 850 nm and 900 nm) according to the definition of ITS-90 relying on the copper and silver point blackbodies and relative spectral responsivity measurements of LP4. The linearity of LP4 is measured by the flux-addition method using two LED arrays over the whole temperature range. The uncertainties of LP4 are confirmed by comparing the temperature difference between the silver and the copper point and by comparing the temperature scales for the 4 spectral bands. For the range from 273 K to 1234K, we calibrate a pyroelectric detector-based thermometer (TRT2) using Ice, Ga, In and Sn point blackbodies for the low range and using Sn, Zn, Al and Ag point blackbodies for the medium range. The uncertainties of the realized scale is 0.1 K to 1.3 K (k=2) from 273 K to 2900 K. The scales are confirmed by comparisons between them at the overlapped ranges and comparisons with an SPRT in a water bath blackbody.

Yoo, Y. S.; Park, C. W.; Kim, B. H.; Park, S. N.

2013-09-01

141

Initial Characterization of a BGO-Photodiode Detector for High Resolution Positron Emission Tomography.  

National Technical Information Service (NTIS)

Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon p...

S. E. Derenzo

1983-01-01

142

Investigation of depth-of-interaction by pulse shape discrimination in multicrystal detectors read out by avalanche photodiodes  

SciTech Connect

The measurement of depth of interaction (DOI) within detectors is necessary to improve resolution uniformity across the FOV of small diameter PET scanners. DOI encoding by pulse shape discrimination (PSD) has definite advantages as it requires only one readout per pixel and it allows DOI measurement of photoelectric and Compton events. The PSD time characteristics of various scintillators were studied with avalanche photodiodes (APD) and the identification capability was tested in multi-crystal assemblies with up to four scintillators. In the PSD time spectrum of an APD-GSO/LSO/BGO/CsI(Tl) assembly, four distinct time peaks at 45, 26, 88 and 150 ns relative to a fast test pulse, having resolution of 10.6, 5.2, 20 and 27 ns, can be easily separated. Whereas the number and position of scintillators in the multi-crystal assemblies affect detector performance, the ability to identify crystals is not compromised. Compton events have a significant effect on PSD accuracy, suggesting that photopeak energy gating should be used for better crystal identification. However, more sophisticated PSD techniques using parametric time-energy histograms can also improve crystal identification in cases where PSD time or energy discrimination alone is inadequate. These results confirm the feasibility of PSD DOI encoding with APD-based detectors for PET.

Saoudi, A.; Pepin, C.M.; Dion, F.; Bentourkia, M.; Lecomte, R. [ Univ. de Sherbrooke, Quebec (Canada). Dept. of Nuclear Medicine and Radiobiology; Andreaco, M.; Casey, M.; Nutt, R. [CTI PET Systems Inc., Knoxville, TN (United States); Dautet, H. [EG and G Optoelectronics, Vaudreuil, Quebec (Canada)

1999-06-01

143

The Indiana silicon sphere 4? charged-particle detector array  

Microsoft Academic Search

A low threshold charged particle detector array for the study of fragmentation processes in light-ion-induced reactions has been constructed and successfully implemented at the IUCF and Saturne II accelerators. The array consists of 162-triple-element detector telescopes mounted in a spherical geometry and covering 74% of 4? in solid angle. Telescope elements are composed of (1) an axial-field gas ionization chamber

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

1995-01-01

144

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

145

Monolithic arrays of silicon drift detectors for medical imaging applications and related CMOS readout electronics  

NASA Astrophysics Data System (ADS)

Monolithic arrays of Silicon Drift Detectors (SDDs) have been recently proposed to be used with scintillators for high-position-resolution ?-ray imaging applications. Thanks to the low electronics noise due to the small value of the output capacitance, the SDD offers better performances with respect to conventional photodiodes of the same geometry. We show the results achieved with a small monolithic array of SDDs, each one with a front-end JFET integrated at its center, used as photodetector in a first prototype of Anger Camera. An intrinsic resolution better than 200 ?m has been achieved with this prototype. Moreover, we describe a new monolithic array of SDDs composed of 77 single hexagonal units, each one with an active area of 8.7 mm2, for a total active area of the device of 6.7 cm2. Finally, the basic principles and the first results of the CMOS readout chip specifically designed for the readout of the signals from SDDs arrays are presented.

Fiorini, C.; Longoni, A.; Porro, M.; Perotti, F.; Lechner, P.; Strüder, L.

2006-05-01

146

A new type UV-visible DOAS system based on photodiode array (PDA)  

Microsoft Academic Search

DOAS technique provides a more representative picture of air quality and typical urban exposures over traditional point monitoring equipments it has been widely used for urban air quality monitoring in China. Most commercial DOAS instruments presently used for air quality monitoring adopt photomultiplier and scanning slit as detector which is called slotted disk (SD) detector. In contrast with the SD

Min Qin; Pinhua Xie; Jianguo Liu; Wenqing Liu; Wu Fang; Fan Lu; Ang Li; Ke Dou; Shisheng Liu; Qingnong Wei

2005-01-01

147

Gamma-spectrometry with Compton suppressed detectors arrays  

Microsoft Academic Search

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

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

1985-01-01

148

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

149

Gamma-spectrometry with Compton suppressed detectors arrays  

SciTech Connect

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

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

1985-01-01

150

Measuring the Energy Spectrum with Telescope Array Surface Detector  

Microsoft Academic Search

The Telescope Array experiment (TA) is the largest cosmic ray experiment in the northern hemisphere. It consists of a surface detector (SD) of 507 scintillation counters and three fluorescence detector stations overlooking the SD. We are analyzing the SD data using a new technique, which consists of generating a Monte Carlo (MC) simulation of the SD that has all the

Dmitri Ivanov; Benjamin Stokes; Gordon Thomson

2010-01-01

151

Energy Spectrum Measured with Telescope Array Surface Detector  

Microsoft Academic Search

The Telescope Array experiment (TA) is the largest cosmic ray experiment in the northern hemisphere. It consists of a surface detector (SD) of 507 scintillation counters and three fluorescence detector stations overlooking the SD. We are analyzing the data collected by TA SD using a new technique which consists of generating a Monte Carlo (MC) simulation with all characteristics of

Dmitri Ivanov; Benjamin Stokes; Gordon Thomson

2011-01-01

152

Optimisation on the two-layer stack gamma detectors of CsI(Tl) coupled with a pin photodiode for non-destructive testing.  

PubMed

This paper proposed the two-layer stack scintillator-coupled photodiode detector to improve the measurement accuracy of the gamma-ray scanning. Both MCNPX and DETECT97 code were used to design the detector. The two manufactured two-layer stack gamma detectors were used to measure the density profile of the distillation column of the radiographic non-intrusive process diagnostic area. To compare the measurement accuracy of the density profile through the non-destructive transmission test, the relative error of the four fluids used for the process diagnostics was analysed. To summarise the measurement results with regard to the relative error of the NaI(Tl) detector and the manufactured detector by material as well as the total relative error, the total relative error of the NaI(Tl) detector was about 15.7 %, whereas that of the two-layer stack CsI(Tl) with photodiode detectors were about 5 %. This paper confirmed that the measurement accuracy of the detector proposed was improved by about three times as compared with the NaI(Tl) detector mostly used for non-destructive testing. PMID:21561939

Bai, Jin Hyoung; Whang, Joo Ho

2011-05-11

153

The Versatile Array of Neutron Detectors at Low Energy (VANDLE)  

SciTech Connect

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new array of plastic scintillator bars under development for measurements at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The array is highly modular allowing the configuration of the individual elements to be optimized for particular experimental requirements. Proposed experiments include (d,n) reactions and beta-delayed neutron emission studies relevant to nuclear astrophysics.

Matei, Catalin [Oak Ridge Associated Universities (ORAU); Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Cizewski, J. A. [Rutgers University; Grzywacz, R. K. [University of Tennessee; Liddick, Sean [University of Tennessee, Knoxville (UTK); Peters, W. A. [Rutgers University; Sarazin, F. [Colorado School of Mines, Golden

2009-01-01

154

Design of micro-sensor-array detector for toxic gas  

Microsoft Academic Search

To quickly measure the trace concentration of the single component toxic gas (e.g. sarin), a micro-array toxic gas detector is designed. A 3 x 3 gas sensor array with metalloporphyrins as sensitive materials is introduced. A micro-capsule that can be easy to be loaded and unloaded is designed for the gas reaction. A fiber-array optical path is designed, which is

Hai-Yang Liao; Peng Tian

2010-01-01

155

Superconducting-nanowire single-photon-detector linear array  

NASA Astrophysics Data System (ADS)

We designed, fabricated, and tested a one-dimensional array of superconducting-nanowire single-photon detectors, integrated with on-chip inductors and resistors. The architecture is suitable for monolithic integration on a single chip operated in a cryogenic environment, and inherits the characteristics of individual superconducting-nanowire single-photon detectors. We demonstrated a working array with four pixels showing position discrimination and a timing jitter of 124 ps. The electronic crosstalk between the pixels in the array was negligible.

Zhao, Qingyuan; McCaughan, Adam; Bellei, Francesco; Najafi, Faraz; De Fazio, Domenico; Dane, Andrew; Ivry, Yachin; Berggren, Karl K.

2013-09-01

156

Towards large scale HTS Josephson detector arrays for THz imaging  

NASA Astrophysics Data System (ADS)

We present the design and implementation of a high-temperature superconducting (HTS) Josephson junction detector array for terahertz (THz) imaging. The array device is made of ten YBa2Cu3Ox?7 (YBCO) step-edge junctions coupled to gold thin-film ring-slot antennas on a MgO substrate. The design and characterization of the detector array in response to a 0.6 THz signal are presented. The development of multi-channel biasing and read-out electronics and the system integration with a commercial cryocooler are also described.

Du, J.; Hellicar, A. D.; Leslie, K. E.; Nikolic, N.; Hanham, S. M.; Macfarlane, J. C.; Foley, C. P.

2013-11-01

157

Silicon photodiode characterization from 1 eV to 10 keV  

SciTech Connect

Silicon photodiodes offer a number of advantages over conventional photocathode type soft x-ray detectors in pulsed power experiments. These include a nominally flat response, insensitivity to surface contamination, low voltage biasing requirements, sensitivity to low energy photons, excellent detector to detector response reproducibility, and ability to operate in poor vacuum or gas backfilled experiments. Silicon photodiodes available from International Radiation Detectors (IRD), Torrance, California have been characterized for absolute photon response from 1 eV to 10 keV photon energy, time response, and signal saturation levels. The authors have assembled individually filtered photodiodes into an array designated the XUV-7. The XUV-7 provides seven photodiodes in a vacuum leak tight, electrically isolated, low noise, high bandwidth, x-ray filtered assembly in a compact package with a 3.7 cm outside diameter. In addition they have assembled the diodes in other custom configurations as detectors for spectrometers. Their calibration measurements show factor of ten deviations from the silicon photodiode theoretical flat response due to diode sensitivity outside the center `sensitive area`. Detector response reproducibility between diodes appears to be better than 5%. Time response measurements show a 10-90% rise time of about 0.1 nanoseconds and a fall time of about 0.5 nanoseconds. Silicon photodiodes have proven to be a versatile and useful complement to the standard photocathode detectors for soft x-ray measurement and are very competitive with diamond for a number of applications.

Idzorek, G.C.; Bartlett, R.J.

1997-10-01

158

Development of Molecular Beam Epitaxially Grown Hg1-x Cd x Te for High-Density Vertically-Integrated Photodiode-Based Focal Plane Arrays  

NASA Astrophysics Data System (ADS)

Hg1-x Cd x Te samples of x ~ 0.3 (in the midwave infrared, or MWIR, spectral band) were prepared by molecular beam epitaxy (MBE) for fabrication into 30-?m-pitch, 256 × 256, front-side-illuminated, high-density vertically-integrated photodiode (HDVIP) focal plane arrays (FPAs). These MBE Hg1-x Cd x Te samples were grown on CdZnTe(211) substrates prepared in this laboratory; they were ~10-?m thick and were doped with indium to ~5 × 1014 cm-3. Standard HDVIP process flow was employed for array fabrication. Excellent array performance data were obtained from these MWIR arrays with MBE HgCdTe material. The noise-equivalent differential flux (NE??) operability of the best array is 99.76%, comparable to the best array obtained from liquid-phase epitaxy (LPE) material prepared in this laboratory.

Aqariden, F.; Dreiske, P. D.; Kinch, M. A.; Liao, P. K.; Murphy, T.; Schaake, H. F.; Shafer, T. A.; Shih, H. D.; Teherani, T. H.

2007-08-01

159

Determination and identification of isoflavonoids in Radix astragali by matrix solid-phase dispersion extraction and high-performance liquid chromatography with photodiode array and mass spectrometric detection  

Microsoft Academic Search

The isoflavonoids in Radix astragali were determined and identified by HPLC–photodiode array detection–MS after extraction employing matrix solid-phase dispersion (MSPD). As a new sample preparation method for R. astragali, the MSPD procedure was optimized, validated and compared with conventional methods including ultrasonic and Soxhlet extraction. The amounts of two major components in this herb, formononetin (6) and ononin (2), were

H. B. Xiao; M. Krucker; K. Albert; X. M. Liang

2004-01-01

160

Determination of nitrofuran residues in avian eggs by liquid chromatography–UV photodiode array detection and confirmation by liquid chromatography–ionspray mass spectrometry  

Microsoft Academic Search

A high-performance liquid chromatographic–UV–Vis photodiode-array detection (HPLC–DAD) method for the determination of nitrofuran residues, nitrofurazone, furazolidone and furaltadone, in chicken eggs is described. Confirmation of the identity of nitrofurazone, furazolidone and furaltadone was performed by high-performance liquid chromatography–mass spectrometry (HPLC–MS) using an atmospheric pressure ionization (API) source and an ionspray interface. The nitrofuran residues were extracted from eggs with acetonitrile

Rosa Draisci; Luigi Giannetti; Luca Lucentini; Luca Palleschi; Gianfranco Brambilla; Luigi Serpe; Pasquale Gallo

1997-01-01

161

Simultaneous determination of 12 chemical constituents in the traditional Chinese Medicinal Prescription Xiao-Yao-San-Jia-Wei by HPLC coupled with photodiode array detection  

Microsoft Academic Search

An HPLC-photodiode array (PDA) detection method was established for the simultaneous determination of 12 components in Xiao-Yao-San-Jia-Wei (XYSJW): geniposide, puerarin, paeoniflorin, ferulic acid, liquiritin, hesperidin, naringin, paeonol, daidzein, glycyrrhizic acid, honokiol, and magnolol. These were separated in less than 70min using a Waters Symmetry Shield RP 18 column with gradient elution using (A) acetonitrile, (B) water, and (C) acetic acid

Hongmin Zhang; Shiwei Chen; Feng Qin; Xi Huang; Ping Ren; Xinqi Gu

2008-01-01

162

Quantitative Determination of 14 Major Constituents in the Herbal Preparation Luan-Pao-Prescription Using HPLC Coupled with Photodiode Array Detection  

Microsoft Academic Search

High performance liquid chromatography coupled with photodiode array detection (HPLC–DAD) was employed for the determination\\u000a of 14 major constituents in traditional Chinese herbal formula ‘Luan-Pao-Prescription’. Two different chromatographic determinations\\u000a for the 14 constituents were carried out to control the quality of this herbal formula. The sample was extracted under ultrasonic\\u000a extraction with 75% methanol at the frequency of 42 kHz for

Jin-qiang Zhang; Xiao-ming Wang; Zhi-qiang Lu; Hui-lian Huang; Guang-tong Chen; Rong-xia Liu; Kai-shun Bi; De-an Guo

2007-01-01

163

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

164

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

165

Design Considerations for Large Format FIR Array Detectors  

NASA Astrophysics Data System (ADS)

Efficient long wavelength broadband and spectral imaging on SOFIA and in future FIR/sub-mm missions will require large two-dimensional detector arrays. While monolithic near infrared arrays of up to 2048 x 2048 pixels are available, observations at wavelengths beyond 40 microns are still limited to mosaics of 32 x 32 or less pixels. We describe how to combine state-of-the-art FIR/sub-mm photoconductor technology and the elaborate industrial production techniques of the near and mid-infrared to produce larger, more reliable and eventually easier to make long wavelength arrays. This approach includes monolithic photoconductor array configurations optimized for quantum efficiency and dark current. For electrical connection to a two-dimensional readout chip indium bump bonds similar to those in shorter wavelengths large-format arrays are used. The readout is based on the successful cryo-CMOS technology developed for SIRTF and SOFIA/AIRES. Differences in thermal contraction between detector and readout materials are addressed using techniques developed for large HgCdTe arrays. Initially, we plan on extrinsic Germanium photoconductor arrays of up to 128 x 128 pixels for wavelengths out to 130 microns. Longer wavelengths can be covered as blocked-impurity band Germanium, GaAs or other new detectors become available. Larger arrays may become feasible once the design concepts have been proven.

Wolf, Juergen; Hoffman, Alan W.; Beeman, Jeffrey W.; Farhoomand, Jam

166

Signal detectability in diffusive media using phased arrays in conjunction with detector arrays.  

PubMed

We investigate Hotelling observer performance (i.e., signal detectability) of a phased array system for tasks of detecting small inhomogeneities and distinguishing adjacent abnormalities in uniform diffusive media. Unlike conventional phased array systems where a single detector is located on the interface between two sources, we consider a detector array, such as a CCD, on a phantom exit surface for calculating the Hotelling observer detectability. The signal detectability for adjacent small abnormalities (2 mm displacement) for the CCD-based phased array is related to the resolution of reconstructed images. Simulations show that acquiring high-dimensional data from a detector array in a phased array system dramatically improves the detectability for both tasks when compared to conventional single detector measurements, especially at low modulation frequencies. It is also observed in all studied cases that there exists the modulation frequency optimizing CCD-based phased array systems, where detectability for both tasks is consistently high. These results imply that the CCD-based phased array has the potential to achieve high resolution and signal detectability in tomographic diffusive imaging while operating at a very low modulation frequency. The effect of other configuration parameters, such as a detector pixel size, on the observer performance is also discussed. PMID:21716463

Kang, Dongyel; Kupinski, Matthew A

2011-06-20

167

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

168

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

169

Feasibility study to determine correct focus by analyzing photon distributions on Geiger-mode avalanche photodiode focal plane array  

NASA Astrophysics Data System (ADS)

A method to determine correct focus in direct detection laser radar system using Geiger-mode avalanche photodiode focal plane array (GmAPD-FPA) is proposed. It is implemented by laser pulses with controlled beam diameter and energy on a distant target. And the time-of-flight (TOF) of laser pulses are obtained for each pixel in GmAPD-FPA. With multiple laser pulses, time correlated single photon counting (TCSPC) is carried out to obtain target detection probability. Using target detection probabilities of each pixel, the photon distribution on GmAPD-FPA is acquired. The condition to determine correct focus is the minimum photon distribution in GmAPD-FPA. In theory part, the range of laser pulse energy is decided. The experiments are carried out with commercial 1x8 pixel GmAPD-FPA. The experimental results show that the focus position is founded using this method and a spatial resolution of a laser radar system is improved where the 1x8 pixel GmAPD-FPA is located in focus position.

Kim, Tae Hoon; Kong, Hong Jin; Jo, Sung Eun; Oh, Min Seok

2011-05-01

170

Analysis of six benzodiazepines in vitreous humor by high-performance liquid chromatography-photodiode-array detection.  

PubMed

The purpose of this study was to validate a high-performance liquid chromatography-photodiode-array detetion method for the determination of six benzodiazepines in vitreous humor. The sample preparation was carried out using solid-phase extraction with Oasis HLB cartridges and 10% acetic acid/MeOH as elution solvent. The vitreous humor is less affected by postmortem changes and is a very useful sample when blood or urine specimens are not available. Linear curves for bromazepam, alprazolam, lorazepam, lormetazepam, diazepam, and tetrazepam were obtained within the range 0.03-3 ?g/mL, with coefficients of correlation lower than 0.999. The limit of detection was 3 ng/mL, and the lower limit of quantification was 30 ng/mL for each benzodiazepine. Intra- and interassay for precision and accuracy provided results less than 16.81% and 16.78%, respectively. Recoveries were higher than 68.51% in all cases. Finally, the method was applied to determine benzodiazepines in vitreous humor from intoxicated patients. PMID:21073805

Cabarcos, P; Tabernero, M J; Álvarez, I; López, P; Fernández, P; Bermejo, A M

2010-11-01

171

Determination of HT-2 and T-2 toxins in oats and wheat by ultra-performance liquid chromatography with photodiode array detection.  

PubMed

European intake estimates indicate that the presence of HT-2 and T-2 toxins in cereals, mainly in oats, can be of concern for human health. Therefore, the development of sensitive, rapid and reliable methods for determining these mycotoxins in cereals, in particular oats, has high priority. A rapid ultra-performance liquid chromatographic (UPLC) method has been developed for the simultaneous determination of HT-2 and T-2 toxins in oats and wheat at ?g kg(-1) level. Ground samples were extracted with methanol/water (90:10, v/v) and the diluted extracts were cleaned up through immunoaffinity columns. HT-2 and T-2 toxins were separated and quantified by UPLC with photodiode array (PDA) detector (?=202 nm) in less than 5 min. Mean recoveries from blank oats samples spiked with HT-2 and T-2 toxins at levels of 50-1000 ?g kg(-1) ranged from 87 to 96%, with relative standard deviations (RSDs) lower than 7%; mean recoveries from wheat spiked with HT-2 and T-2 toxins at levels of 25-100 ?g kg(-1) ranged from 91 to 103%, with RSDs lower than 5%. The limit of detection of the method was 8 ?g kg(-1) for both toxins (signal-to-noise ratio 3:1). The method was successfully applied to the analysis of HT-2 and T-2 toxins in naturally contaminated oats and wheat samples. A good correlation was found by comparative analysis of naturally contaminated samples of oats (r=0.9985) and wheat (r=0.9058) using the proposed method or a reliable HPLC method with fluorescence detection after pre-column derivatization with 1-anthroylnitrile. PMID:22284485

Pascale, Michelangelo; Panzarini, Giuseppe; Visconti, Angelo

2011-12-09

172

Beam profile shaping for laser radars that use detector arrays.  

PubMed

The beam shaper we developed shapes the transmit beam of a CO(2) laser radar that uses a linear detector array. It consists of a diffraction grating and an anamorphic prism beam compressor and produces a stretched profile that efficiently and uniformly illuminates the far-field footprint of the detector array. The diffraction grating phase modulates the near field or the laser beam to generate a far-field flattop intensity profile, whereas the compressor produces the necessary profile eccentricity. We have achieved conversion efficiencies in the 70-90% range. PMID:20372453

Veldkamp, W B; Kastner, C J

1982-01-15

173

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

174

Influence of temperature and bias voltage on the performance of a high resolution PET detector built with position sensitive avalanche photodiodes  

NASA Astrophysics Data System (ADS)

We evaluate the performance of an 8 × 8 array of 0.9 × 0.9 × 1 mm3 cerium doped lutetium oxyothosilicate (LSO) crystals coupled to a position sensitive avalanche photodiode (PSAPD) as a function of bias voltage and temperature. We use this detector to develop a general methodology to optimize bias voltage, temperature, and gain for PET detectors using semiconductor photodetectors. This detector module will be used in a novel high resolution positron emission tomography (PET) camera dedicated to breast imaging under construction in our lab. Due to the tight packing of many PSAPDs in the system a thermal gradient is expected across the imaging heads. Data were collected for 11 PSAPD temperatures between 5°C and 40°C using a thermo-electric (Peltier) device. At each temperature the bias voltage was varied in steps of 5 V over a 50 V range. We present three methods to predict the optimal bias voltage at every temperature: one based on optimizing the coincidence time resolution, the others based on the relative change in PSAPD gain and leakage current due to the onset of hole multiplication. Optimal gain could also be predicted based on the quality of the flood histogram. At optimal bias voltage, the energy resolution degrades as (10.5±0.1)+((0.038±0.006)/ °C·T)%. Time resolution stays constant at 2.37±0.02 ns below 15°C. Above this temperature, time resolution deteriorates as (1.67±0.06)+((0.042±0.002)/°C·T)ns. Even at high temperatures, all 64 crystal position peaks in the flood histogram are still clearly visible. The width of the peaks in the flood histogram show a quadratic degradation with temperature: (2.6±0.1)·10-2+(1.6±0.2)·10-5/(°C)2·T2. We conclude that both the quality of the flood histogram as well as the coincidence time resolution are better parameters to estimate the optimal bias voltage, than energy resolution. Optimal bias voltage is found to be dependent on the value of k, the ratio between hole and electron multiplication. We achieve optimal bias at a similar gain at all temperatures. The optimal bias voltage changes linearly across the observed range.

Vandenbroucke, A.; McLaughlin, T. J.; Levin, C. S.

2012-08-01

175

Microlens arrays with integrated thin film power monitors  

Microsoft Academic Search

VCSEL 1D or 2D arrays for parallel optical interconnect links require monitor photodiodes, but conventional discrete detectors as used in single lasers are not feasible for arrays. Aegis Semiconductor is developing 1D and 2D `smart' microlens arrays with integrated power monitor sensors in the form of semi-transparent thin film silicon and silicon-germanium based photodiodes direct deposited by PECVD. The developmental

Eugene Ma; Adam Payne; Nikolay Nemchuk; Lawrence Domash

2001-01-01

176

The Fluorescence Detectors of the Telescope Array Experiment  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA), the first dedicated Northern Hemisphere ``hybrid'' ultrahigh energy cosmic ray (UHECR) detector, is online in Millard Country, Utah. The three Fluorescence Detector sites (FD) located at Black Rock Mesa, Long Ridge and Middle Drum have been taking data since November 2007. By measuring the characteristics of UHECR-induced extensive air showers using the FD, we can measure the energies, composition and arrival directions of the highest-energy cosmic rays. We will show preliminary data from the experiment and comparisons with simulated data from our full detector Monte Carlo simulation program.

Scott, Lauren

2009-05-01

177

An Event Reconstruction Method for the Telescope Array Fluorescence Detectors  

SciTech Connect

We measure arrival directions, energies and mass composition of ultra-high energy cosmic rays with air fluorescence detector telescopes. The longitudinal profile of the cosmic ray induced extensive air shower cascade is imaged on focal plane of the telescope camera. Here, we show an event reconstruction method to obtain the primary information from data collected by the Telescope Array Fluorescence Detectors. In particular, we report on an ''Inverse Monte Carlo (IMC)'' method in which the reconstruction process searches for an optimum solution via repeated Monte Carlo simulations including characteristics of all detectors, atmospheric conditions, photon emission and scattering processes.

Fujii, T.; Ogio, S.; Yamazaki, K. [Graduate Schiool of Science, Osaka City University, Sumiyoshi, Osaka 558-8585 (Japan); Fukushima, M.; Ikeda, D.; Sagawa, H.; Takahashi, Y.; Tameda, Y. [Institute of Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Hayashi, K.; Ishimori, R.; Kobayashi, Y.; Tokuno, H.; Tsunesada, Y. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Honda, K.; Tomida, T. [Graduate School of Medicine and Engineering, University of Yamanashi, Kofu, Yamanashi 400-8511 (Japan); Udo, S. [Faculty of Engineering, Kanagawa University, Yokohama, Kanagawa 221-8686 (Japan)

2011-09-22

178

Reflectance colorimetry measurement system using scanning spectrometer with array detector  

NASA Astrophysics Data System (ADS)

A reflectance colorimetry measurement system is constructed using scanning spectrometer with array detector, and the color measurement can be achieved under 45:0 and 0:45 geometry conditions. Typically, there are two types of spectrometer for colorimetry measurement: the scanning spectrometer with single-channel detector requires point-by-point spectral reading, and the measurement is time consuming; array sensor spectrometer (multichannel spectrometer) can completes the measurement in a few milliseconds, but its spectral resolution and range are limited by the array sensor and the optical elements. This colorimetry measurement system is designed for color calibration service, it using a scanning spectrometer with array detector, which divides the board spectral measurement range into sections, and uses the array detector to measure each section respectively, thus achieving the rapid measurement of spectral data with high resolution and wide wavelength range, so as to realized fast color measurement with high precision. The array sensor of the system using a photo diode array (PDA) with 1024 pixel, having a larger dynamic range and better linearity compared to CCD. The grating is rotated with a precision rotation stage, and the rotation angle is calculated basing the parameters of grating and collimator lens, so as to stitch the spectral data of each measurement section., the measurement signal is mutated at the junction point between measurement sections, due to the rotation angle and the shape of grating efficiency curve. The theoretical analysis and experiment shows that the signal mutation at the junction point can be eliminated by comparison measurement of reflectance.

Sun, Ruoduan; Ma, Yu; Dai, Caihong; Chen, Xiaju

2013-08-01

179

Technologies for superconducting nanowire single-photon detector array system  

NASA Astrophysics Data System (ADS)

We present the development of key technologies for realization of superconducting nanowire single photon detector array system, which enables high counting rates, and allow spatial and pseudo photon number resolution. Toward the realization of practical large-scale SSPD array system, primary issue is how to avoid heat flow into cryocooler system. One of the challenging tasks is the development of their readout electronics. In the conventional readout technique used for single pixel devices, the number of high-frequency coaxial cables increases proportionally with the number of arrays. This causes a significant increase in the heat load from room temperature, which makes the implementation of the SSPD arrays in a compact refrigerator difficult. To overcome this problem, we proposed applying readout electronics with superconducting single-flux-quantum (SFQ) logic circuitsWe show the implementation and successful operation of four pixels SSPD array connected to SFQ readout electronics with parallel bias scheme in a 0.1W GM cryocooler system.

Miki, Shigehito; Yamashita, Taro; Terai, Hirotaka; Makise, Kazumasa; Wang, Zhen

2013-06-01

180

Analysis Techniques used for Telescope Array Surface Detector Data  

Microsoft Academic Search

The Telescope Array experiment is the largest cosmic ray experiment in the northern hemisphere. It consists of a surface detector (SD) of 507 scintillation counters and three fluorescence stations overlooking the SD. We are analyzing the SD data using a new technique, which consists of generating a Monte Carlo (MC) simulation of the SD that has all the characteristics of

Dmitri Ivanov; Benjamin Stokes; Gordon Thomson

2009-01-01

181

MUST: A silicon strip detector array for radioactive beam experiments  

Microsoft Academic Search

A new and innovative array, MUST, based on silicon strip technology and dedicated to the study of reactions induced by radioactive beams on light particles is described. The detector consists of 8 silicon strip – Si(Li) telescopes used to identify recoiling light charged particles through time of flight, energy loss and energy measurements and to determine precisely their scattering angle

Y. Blumenfeld; F. Auger; J. E. Sauvestre; F. Maréchal; S. Ottini; N. Alamanos; A. Barbier; D. Beaumel; B. Bonnereau; D. Charlet; J. F Clavelin; P. Courtat; P. Delbourgo-Salvador; R. Douet; M. Engrand; T. Ethvignot; A. Gillibert; E. Khan; V. Lapoux; A. Lagoyannis; L. Lavergne; S. Lebon; P. Lelong; A. Lesage; V. Le Ven; I. Lhenry; J. M Martin; A. Musumarra; S. Pita; L. Petizon; E. Pollacco; J. Pouthas; A. Richard; D. Rougier; D. Santonocito; J. A Scarpaci; J. L Sida; C. Soulet; J. S Stutzmann; T. Suomijärvi; M. Szmigiel; P. Volkov; G. Voltolini

1999-01-01

182

Performance characterization of a MVCT scanner using multislice thick, segmented cadmium tungstate-photodiode detectors  

SciTech Connect

Purpose: Megavoltage computed tomography (MVCT) and megavoltage cone beam computed tomography (MVCBCT) can be used for visualizing anatomical structures prior to radiation therapy treatments to assist in patient setup and target localization. These systems are less susceptible to metal artifacts and provide better CT number linearity than conventional CT scanners. However, their contrast is limited by the properties of the megavoltage photons and the low detective quantum efficiency (DQE) of flat panel detector systems currently available. By using higher DQE, thick, segmented cadmium tungstate detectors, the authors can improve the low contrast detectability of a MVCT system. This in turn would permit greater soft tissue visualization for a given radiation dose, allowing MVCT to be used in more clinical situations. Methods: This article describes the evaluation of our prototype system that uses thick, segmented detectors. In order to create images using a dose that would be acceptable for day to day patient imaging, the authors evaluated their system using the low intensity bremsstrahlung component of a 6 MeV electron beam. The system was evaluated for its uniformity, high contrast resolution, low contrast detectability, signal to noise ratio, contrast to noise ratio, and CT number linearity. Results: The prototype system was found to have a high contrast spatial resolution of about 5 line pairs per cm, and to be able to visualize a 15 mm 1.5% contrast target with 2 cGy of radiation dose delivered. SNR{sup 2} vs radiation dose and mean pixel value vs electron density curves were linear. Conclusions: This prototype system shows a large improvement in low contrast detectability over current MVCBCT systems.

Kirvan, P. F.; Monajemi, T. T.; Fallone, B. G.; Rathee, S. [Department of Physics, University of Alberta, Edmonton, Alberta T6E 2E1 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Physics, University of Alberta, Edmonton, Alberta T6E 2E1 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

2010-01-15

183

Experimental realization of a metamaterial detector focal plane array.  

PubMed

We present a metamaterial absorber detector array that enables room-temperature, narrow-band detection of gigahertz (GHz) radiation in the S band (2-4 GHz). The system is implemented in a commercial printed circuit board process and we characterize the detector sensitivity and angular dependence. A modified metamaterial absorber geometry allows for each unit cell to act as an isolated detector pixel and to collectively form a focal plane array . Each pixel can have a dedicated microwave receiver chain and functions together as a hybrid device tuned to maximize the efficiency of detected power. The demonstrated subwavelength pixel shows detected sensitivity of -77 dBm, corresponding to a radiation power density of 27 nW/m(2), with pixel to pixel coupling interference below -14 dB at 2.5 GHz. PMID:23215222

Shrekenhamer, David; Xu, Wangren; Venkatesh, Suresh; Schurig, David; Sonkusale, Sameer; Padilla, Willie J

2012-10-24

184

Experimental Realization of a Metamaterial Detector Focal Plane Array  

NASA Astrophysics Data System (ADS)

We present a metamaterial absorber detector array that enables room-temperature, narrow-band detection of gigahertz (GHz) radiation in the S band (2-4 GHz). The system is implemented in a commercial printed circuit board process and we characterize the detector sensitivity and angular dependence. A modified metamaterial absorber geometry allows for each unit cell to act as an isolated detector pixel and to collectively form a focal plane array . Each pixel can have a dedicated microwave receiver chain and functions together as a hybrid device tuned to maximize the efficiency of detected power. The demonstrated subwavelength pixel shows detected sensitivity of -77dBm, corresponding to a radiation power density of 27nW/m2, with pixel to pixel coupling interference below -14dB at 2.5 GHz.

Shrekenhamer, David; Xu, Wangren; Venkatesh, Suresh; Schurig, David; Sonkusale, Sameer; Padilla, Willie J.

2012-10-01

185

A readout for large arrays of microwave kinetic inductance detectors  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

186

In-orbit performance of avalanche photodiode as radiation detector on board the picosatellite Cute-1.7+APD II  

NASA Astrophysics Data System (ADS)

The Cute-1.7+APD II, 10 × 15 × 20 cm3 in size and 5 kg in mass, is the third picosatellite developed by students at the Tokyo Institute of Technology. One of the primary goals of the Cute-1.7+APD II mission is to validate the use of avalanche photodiodes (APDs) as a radiation detector for the first time in a space experiment. While the mission itself is immature compared to the forefront satellites of space plasma physics, use of APDs offers various possibilities regarding a brand-new electron energy analyzer for medium-energy electrons and ions (1-100 keV), as well as a high-performance light sensor for the future X-ray astronomy missions. The satellite was successfully launched by ISRO PSLV-C9 rocket on 28 April 2008 and has since been in operation for more than a year. The Cute-1.7+APD II carries two reverse-type APDs to monitor the distribution of low-energy particles (mainly electrons and protons) down to 9.2 keV trapped in a low Earth orbit (LEO), including the South Atlantic Anomaly (SAA) as well as aurora bands. We present the design parameters and various preflight tests of the APDs prior to launch, particularly, the high counting response and active gain control system for the Cute-1.7+APD II mission. Examples of electron/proton distribution, obtained in continuous 12 h observations, will be presented to demonstrate the initial flight performance of the APDs in orbit.

Kataoka, J.; Toizumi, T.; Nakamori, T.; Yatsu, Y.; Tsubuku, Y.; Kuramoto, Y.; Enomoto, T.; Usui, R.; Kawai, N.; Ashida, H.; Omagari, K.; Fujihashi, K.; Inagawa, S.; Miura, Y.; Konda, Y.; Miyashita, N.; Matsunaga, S.; Ishikawa, Y.; Matsunaga, Y.; Kawabata, N.

2010-05-01

187

An automatic gas-phase molecular absorption spectrometric system using a UV-LED photodiode based detector for determination of nitrite and total nitrate.  

PubMed

An automatic gas-phase molecular absorption spectrometric (GPMAS) system was developed and applied to determine nitrite and total nitrate in water samples. The GPMAS system was coupled with a UV-light emitting diode photodiode (UV-LED-PD) based photometric detector, including a 255 nm UV-LED as the light source, a polyvinyl chloride (PVC) tube of 14 cm as the gas flow cell, and an integrated photodiode amplifier to measure the transmitted light intensity. The UV-LED-PD detector was compact, robust, simple and of low heat production, comparing with detectors used in other GPMAS works. For nitrite measurement, citric acid was used to acidify the sample, and ethanol to catalyze the quantitative formation of NO(2). The produced NO(2) was purged with air flow into the UV-LED-PD detector, and the gaseous absorbance value was measured. The total nitrate could be determined after being reduced to nitrite with a cadmium column. Limits of detection for nitrite and nitrate were 7 ?mol/L and 12 ?mol/L, respectively; and linear ranges of 0.021-5 mmol/L for nitrite and 0.036-4 mmol/L for nitrate were obtained. Related standard deviations were 1.81% and 1.08% for nitrite and nitrate, respectively, both at 2 mmol/L. The proposed method has been applied to determine nitrite and total nitrate in some environmental water samples. PMID:21376971

Zhang, Min; Zhang, Zhen; Yuan, Dongxing; Feng, Sichao; Liu, Baomin

2011-01-26

188

A /?-ray detector array for joint spectroscopy experiments at the JAERI tandem-booster facility  

NASA Astrophysics Data System (ADS)

A compact array for /?-ray spectroscopy developed for the joint experiment at the Japan Atomic Energy Research Institute is described. It consists of an array of 11 Compton suppressed Ge detectors, a 4/? silicon detector array for charged particle measurements, a position-sensitive silicon detector for experiments on Coulomb excitation and a conversion-electron spectrometer. The details of the detectors and new experimental results obtained with the compact array are also described.

Furuno, K.; Oshima, M.; Komatsubara, T.; Furutaka, K.; Hayakawa, T.; Kidera, M.; Hatsukawa, Y.; Matsuda, M.; Mitarai, S.; Shizuma, T.; Saitoh, T.; Hashimoto, N.; Kusakari, H.; Sugawara, M.; Morikawa, T.

1999-01-01

189

A variable dispersion array detector for a tandem mass spectrometer  

NASA Astrophysics Data System (ADS)

Incorporation of a pair of quadrupole lenses and one octapole lens after the second magnetic field of a JEOL HX110/HX110 tandem mass spectrometer permits varying the dispersion and therefore the mass range that can be focused on a 2 in array detector. This range can be adjusted from a value of 1: 1.04 to 1: 1.3 for the ratio of low m/z to high m/z falling at the extremes of the detector. The ratio is governed by the d.c. potentials on the lenses which also changes the angle of the resulting focal plane and thus requires that the position of the array detector must be changed accordingly. In the system described, all these variables are under computer control and can be adjusted within 1 s, thus allowing for a change even during the recording of a spectrum if one wishes to minimize the number of segments to be recorded to cover the entire spectrum while still maintaining unit mass resolution. The variable range array detector is useful for the recording of normal mass spectra as well as those generated upon collision induced decomposition (CID) of precursor ions. In the latter case, the refocusing of the ion beams through the quadrupole lens system is more complex but the software controls the lens potentials accordingly. The system has been used to record the normal or CID spectra of peptides, either from a static sample or eluting from a high performance liquid chromatograph.

Hill, James A.; Biller, James E.; Biemann, Klaus

1991-12-01

190

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

191

New approach to detector array receiver performance analysis for laser satellite communication  

Microsoft Academic Search

Laser satellite communication is one of the most promising methods of communication outside the earth's atmosphere. In the continuing quest to optimize atmospheric optical wireless communication, arrays of photodetectors are replacing solitary photodetectors in receivers, affording the advantages of the small fast photodiode while effectively increasing the receiver aperture. Thus, power dispersed by atmospheric turbulence and scattering may be collected

Eyal Kayton; Daniel M. Marom; Shlomi Arnon

2002-01-01

192

Radiation Detectors Scintillator-Photodiode on the Base of A2B6 Crystals for Application in Homeland Security and Medical Equipment  

Microsoft Academic Search

We have studied comparative parameters of different scintillators: CsI(Tl), CdWO4, ZnSe(Te), ZnSe(Te,O) for dual-energy radiography applications. Detectors of the scintillator-photodiode type were obtained on the basis of CsI(Tl), CdWO4 and ZnSe(Te) crystals, and their comparative study was carried out, aiming at their use in X-ray multi-energy tomography. Because of their low afterglow level (10 ppm after 10 ms), CWO and

B. V. Grinyov; V. D. Ryzhikov; S. V. Naydenov; C. F. Smith; A. D. Opolonin; E. K. Lisetskaya; N. A. Shumeiko; N. L. Kurna; G. M. Onischenko; S. E. Tretyak; S. N. Galkin; E. F. Voronkin

2006-01-01

193

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

194

Pyroelectric linear array IR detectors with CCD multiplexer  

NASA Astrophysics Data System (ADS)

Responsive pyroelectric linear arrays are described. After a short representation of the principal detector function, the pyroelectric materials L-alanine doped triglycine sulfate (DTGS:L-A) and lithium niobate (LiNbO3) are characterized, and the system parts pyroelectric chip, CCD-multiplexer, and hybrid arrangement are described in detail. Finally, the measured properties responsivity, noise equivalent power, and modulation transfer function are summarized.

Norkus, Volkmar; Neumann, Norbert; Walther, Ludwig; Hofmann, Guenter; Schieferdecker, Jorg; Krauss, Matthias G.; Budzier, Helmut; Hess, Norbert

1991-08-01

195

A current mode detector array for ? -ray asymmetry measurements  

Microsoft Academic Search

We have built a CsI(Tl) ?-ray detector array for the NPDGamma experiment to search for a small parity-violating directional asymmetry in the angular distribution of 2.2MeV ?-rays from the capture of polarized cold neutrons by protons with a sensitivity of several ppb. The weak pion–nucleon coupling constant can be determined from this asymmetry. The small size of the asymmetry requires

M. T. Gericke; C. Blessinger; J. D. Bowman; R. C. Gillis; J. Hartfield; T. Ino; M. Leuschner; Y. Masuda; G. S. Mitchell; S. Muto; H. Nann; S. A. Page; S. I. Penttilä; W. D. Ramsay; P.-N. Seo; W. M. Snow; J. Tasson; W. S. Wilburn

2005-01-01

196

Testing and characterization of the CYCLOPS HgCdTe focal plane detector array  

NASA Astrophysics Data System (ADS)

Optoelectronics Division has developed an advanced technology demonstrator utilizing an infrared focal plane detector array to assess the feasibility of using passive infrared sensors for ADF applications. To model the performance of the sensor the characteristics of the focal plane detector array have been measured. The measurement of the characteristics of large scale detector arrays and the testing of these arrays present problems which are not encountered with single element infrared detectors. Optoelectronics Division has gained considerable experience in these processes during the development of the 'Cyclops' technology demonstrator. The procedures used in characterizing the HgCdTe focal plane detector array and the results obtained are described.

Poropat, G. V.

1993-08-01

197

CMOS arrays as chemiluminescence detectors on microfluidic devices.  

PubMed

A simple, low-cost process to integrate complementary metal oxide semiconductor array detectors (CMOSAD) for chemiluminescence is presented, evaluated, and applied to the determination of nitrite in ground water samples. CMOS arrays of different brands (obtained from commercial image sensors) were adapted as chemiluminescence detectors on microfluidic devices. The performance of the CMOSADs was evaluated in the visible zone of the spectrum using a tungsten halogen lamp as light source. Intrinsic parameters assessed included signal stability, spectral response, dark current, and signal-to-noise ratio. Thereafter, the CMOSADs were integrated on microfluidic devices and their performances in quantitative analysis were assessed with the chemiluminometric reaction of hydrogen peroxide with luminol, catalyzed with hexacyanoferrate (III). The parameters assessed were sensitivity, linear range, detection limit, reproducibility, correlation coefficient of the calibration curves, and baseline drift during measurements. The CMOSAD with the best performance was selected to assess the applicability of the developed microfluidic devices with the integrated detector. The microfluidic system permitted the determination of nitrite with both good precision and good recovery values in the analysis of ground water samples. Integration was easily achieved and enabled the development of a simple, low-cost, and feasible alternative to conventional detectors. PMID:20177663

Rodrigues, Eunice R G O; Lapa, Rui A S

2010-02-23

198

READOUT SYSTEM FOR ARRAYS OF FRISCH-RING CDZNTE DETECTORS.  

SciTech Connect

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

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

2006-10-29

199

Digital readouts for large microwave low-temperature detector arrays  

NASA Astrophysics Data System (ADS)

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

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

2006-04-01

200

Submillimeter resolution in one-dimensional position measurements of ?-ray photons by using a CsI(Tl) scintillator coupled to a linear array of silicon drift detectors  

NASA Astrophysics Data System (ADS)

We present the one-dimensional (1D) position and energy resolution results obtained by a ?-ray detector based on a single CsI(Tl) scintillator coupled to a linear array of silicon drift detectors (SDDs). The present prototype has been realized in order to investigate the basic performances of this new architecture in view of the realization of Anger cameras for 2D imaging in nuclear medicine, based on the use of SDDs instead of photomultiplier tubes. The SDD provides a high value of quantum efficiency to the scintillation light, typical of a silicon photodetector, and is moreover characterized by a lower value of electronics noise with respect to conventional silicon photodiodes, thanks to the low value of output capacitance. At 122 keV the present detector shows a position resolution better than 0.5 mm FWHM, and an energy resolution of about 13% FWHM. The experimental setup is described and the most significant experimental results are presented.

Fiorini, C.; Labanti, C.; Perotti, F.

2000-08-01

201

X ray and charged particle detection with CsI(Tl) layer coupled to a-Si:H photodiode layers  

NASA Astrophysics Data System (ADS)

A compact real-time X ray and charged particle imager with digitized position output can built either by coupling a fast scintillator to a photodiode array or by forming one on a photodiode array directly. CsI(Tl) layers 100 to 1000 microns thick were evaporated on glass substrates from a crystal CsI(Tl). When coupled to a crystalline Si or amorphous silicon (a-Si:H) photodiode and exposed to calibrated X ray pulses, their light yields and speed were found to be comparable to those of a crystal CsI(Tl). Single beta particle detection was demonstrated with this combination. The light spread inside evaporated CsI(Tl) was suppressed by its columnar structure. Scintillation detection gives much larger signals than direct X ray detection due to the increased energy deposition in the detector material. Fabrication of monolithic type X-ray sensors consisting of CsI + a-Si:H photodiodes is discussed.

Fujieda, I.; Cho, G.; Drewery, J.; Gee, T.; Jing, T.; Kaplan, S. N.; Perez-Mendez, V.; Wildermuth, D.; Street, R. A.

1990-10-01

202

Design of micro-sensor-array detector for toxic gas  

NASA Astrophysics Data System (ADS)

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

Liao, Hai-Yang; Tian, Peng

2010-08-01

203

A miniature dilution refrigerator for sub-Kelvin detector arrays  

NASA Astrophysics Data System (ADS)

We describe a miniature dilution refrigerator (MDR), operated in continuous mode and suitable for many detector applications at temperatures down to 50 mK. It distinguishes itself from other refrigerators in that it is self-contained and benefits from an internal cycle of the 3He gas. As a result, no external gas handling system is required so size, weight and complexity of the system is dramatically decreased. The system has no fine capillaries, moving parts or cooled O-rings. It is therefore mechanically very reliable, has no risk of blockages and is unlikely to develop cryogenic leaks. One direct application is balloon-borne or ground-based observations of the CMB using large detector arrays. When these experiments are operated remotely on platforms or at sites with limited infrastructure and maintenance support, a compact and reliable dilution refrigerator becomes essential. We describe a complete system incorporating an MDR which we have built and integrated with a pulse-tube refrigerator to achieve a cooling power of several micro Watt at 100 mK. This system is being developed for a CMB polarization experiment (CLOVER) which requires three independent cryostats to cool large TES detector arrays.

Teleberg, Gustav; Chase, Simon T.; Piccirillo, Lucio

2006-07-01

204

Geiger-mode avalanche photodiodes for laser communications and laser radar  

Microsoft Academic Search

Arrays of photon-counting avalanche photodiodes (APDs) enable laser-communications and laser-radar receivers with unprecedented sensitivity at 1.06-mum wavelength. Near room temperature, the best detectors have: 50% photon detection efficiency, 30-kHz dark count rate, and a 1-mus reset time to avoid after-pulsing. Arrays with 64 elements were fabricated in the InGaAsP\\/InP materials system and were bump-bonded to a custom CMOS integrated circuit

B. F. Aull; J. C. Aversa; E. A. Dauler; J. P. Donnelly; E. K. Duerr; J. P. Frechette; J. E. Funk; S. H. Groves; P. I. Hopman; K. E. Jensen; Z.-L. Liau; J. M. Mahan; L. J. Mahoney; K. A. McIntosh; A. Napoleone; D. C. Oakley; E. J. Ouellette; D. C. Shaver; G. M. Smith; S. Verghese; C. J. Vineis

2006-01-01

205

The next generation of monolithic infrared detector arrays  

NASA Astrophysics Data System (ADS)

Recently NASA announced an initiative ``X-2000'' whose ultimate goal is ``satellite-on-a-chip.'' We propose advanced, Monolithic InGaAs-on-silicon Short Wave Infrared (SWIR), and Monolithic InSb-on-silicon Medium Wave Infrared (MWIR) detector arrays for X-2000. To achieve ``satellite-on-a-chip'' goal, it is imperative to have a fully integrated Focal Plane Array on one wafer substrate, preferably silicon. A (512×512) High Resolution Focal Plane Array structure is proposed that employs a technique to selectively epitaxially grow InGaAs and InSb photodetectors on silicon substrate. Growth of lattice mis-matched InGaAs and InSb layers on silicon substrate is improved by limiting the growth area, selecting appropriately oriented wafers, as well as controlling the growth conditions, and thus, the RoA product, an important parameter of the photodetectors will be enhanced. At 150 K, the expected RoA is 300 to 400 Kohm-sq. cm for InGaAs and 500 to 1,000 Ohm-sq. cm. for InSb. A new CMOS readout circuit will be developed from the present Discovery Semiconductors' 1D and 2D FPA readout circuits for the (512×512) High Resolution Monolithic InGaAs/InSb-on-Silicon SWIR/MWIR FPA. It has four readout methods suitable for a wide range of RoA product of the IR detectors. The silicon readout circuit will be fabricated by 0.6 um CMOS process technology for obtaining a higher fill factor, readout speed, signal injection, and readout efficiency of the FPA. The above approach addresses the application requirements of NASA's X-2000 initiative and solves some problems inherent to Hybrid Focal Plane Arrays.

Joshi, Abhay M.; Jhabvala, Murzy; Shu, Peter

1998-01-01

206

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

207

Very-high-bandwidth In0.53Ga0.47As p-i-n detector arrays  

Microsoft Academic Search

The authors fabricated and packaged 1*4 arrays of In0.53Ga0.47As p-i-n photodetectors connected in a GaAs FET bias-switched, common cathode circuit. The bandwidth of the discrete (packaged) photodiodes in the arrays exceeds 11 GHz, and is 5 GHz for the packaged arrays. The on\\/off isolation ratio for fully packaged arrays using GaAs FET bias switches was measured at both low and

Y. Lui; S. R. Forrest; G. L. Tangonan; R. A. Jullens; R. Y. Loo; V. L. Jones; D. Persechini; J. L. Pikulski; M. M. Johnson

1991-01-01

208

Dual APD array readout of LSO crystals: optimization of crystal surface treatment  

Microsoft Academic Search

We are developing a compact positron emission tomography (PET) detector module with a depth of interaction capability (DOI) based on a lutetium oxyorthosilicate (LSO) scintillator array coupled at both ends by avalanche photodiode (APD) arrays. This leads to a detector with high sensitivity that can provide high and uniform image resolution. We report studies on improving the DOI resolution by

Y. Shao; K. Meadors; R. W. Silverman; R. Farrell; L. Cirignano; R. Grazioso; K. S. Shah; S. R. Cherry

2002-01-01

209

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

210

Optimal extraction and fingerprint analysis of Cnidii fructus by accelerated solvent extraction and high performance liquid chromatographic analysis with photodiode array and mass spectrometry detections.  

PubMed

A confirmatory and reliable procedure has been developed for extraction and determination of Cnidii fructus by accelerated solvent extraction (ASE) and high-performance liquid chromatography coupled with photodiode array, electrospray ionisation ion trap tandem mass spectrometry and time of flight mass spectrometry (HPLC-PDA-ESI-ITMS(n)/TOF-MS). The determination method enabled the characterisation of sixteen bioactive components in C. fructus and quantification of three major coumarins, namely osthole, imperatorin and isopimpinellin. Response surface methodology (RSM) was employed to optimise the extraction parameters yielding the optimum conditions of ASE (extraction temperature 122 °C, extraction time 5 min and two static cycles). And the total contents of three major coumarins extracted by ASE under the optimum conditions was significantly higher than those by reflux and ultrasonic extraction (P<0.05) with better reproducibility. At last, the proposed method coupled with pattern recognition was applied to analysis of C. fructus from eight different regions in China. PMID:23870916

Gao, Fangyuan; Hu, Yongsheng; Ye, Xiaolan; Li, Ji; Chen, Zhao; Fan, Guorong

2013-05-21

211

Evaluation of principal components analysis with high-performance liquid chromatography and photodiode array detection for the forensic differentiation of ballpoint pen inks.  

PubMed

Inks from seven black and eight blue ballpoint pens were separated by a high-performance liquid chromatography (HPLC) method utilizing a photodiode array detection (PDA). A classifier flowchart was designed for the chromatographic data based on the presence or absence of certain peaks at different wavelengths to qualitatively discriminate between the inks. The same data were quantitatively classified by principal components analysis (PCA) to estimate the separation between a pair of classes of ink samples. It was found that the black ballpoint pen inks were discriminated satisfactorily utilizing two-dimensional data of the peak areas and retention times at the optimum wavelengths. The blue pens were discriminated by analyzing the chromatographic data at four different wavelengths simultaneously with a cross-validated PCA. The results of this study indicated that HPLC-PDA coupled with chemometrics could make a powerful discriminating tool for the forensic chemist, especially when analyzing extensive and/or complex data. PMID:11451070

Kher, A A; Green, E V; Mulholland, M I

2001-07-01

212

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.  

PubMed

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, and the UV peak areas were used for quantitation of the flavonoid contents. Examples of HPLC-MS, analyses of orange pulp, tomato, and apple are presented. The method has been used to screen foods on the Danish market, and the contents of flavones, flavonols, and flavanones were measured. PMID:9550103

Justesen, U; Knuthsen, P; Leth, T

1998-03-13

213

High-performance liquid chromatography with photodiode array detection for determination of nobiletin content in the brain and serum of mice administrated the natural compound.  

PubMed

We recently demonstrated that nobiletin, a citrus flavonoid, exhibits anti-dementia action in animals. However, no determination methods for the content of nobiletin with beneficial action in the brain of nobiletin-administered animals have been developed, nor has its pharmacokinetics been revealed completely. Here, we established the high-performance liquid chromatography/photodiode array detection method for nobiletin determination using Bond Elut C18 SPE cartridges for extraction, where the calibration curve was linear over 0.025-10 ng, with coefficient of variation of less than 6.76%. This method enabled us to determine pharmacokinetic parameters of nobiletin given intraperitoneally or per os in the brain of mice. PMID:21559759

Saigusa, Daisuke; Shibuya, Masatoshi; Jinno, Daisuke; Yamakoshi, Hiroyuki; Iwabuchi, Yoshiharu; Yokosuka, Akihito; Mimaki, Yoshihiro; Naganuma, Akira; Ohizumi, Yasushi; Tomioka, Yoshihisa; Yamakuni, Tohru

2011-05-11

214

A biologically inspired compound-eye detector array-part I: modeling and fundamental limits  

Microsoft Academic Search

This is the first part of a two-part paper. In this paper, we propose a detector array for detecting and localizing sources that emit particles includingphotons, neutrons, or charged particles. The array consists of multiple \\

Zhi Liu; Arye Nehorai; Eytan Paldi

2009-01-01

215

'DIAMANT': A 4 (pi) light charged particle detector array. An efficient tool for nuclear spectroscopy.  

National Technical Information Service (NTIS)

4(pi) (gamma)-spectrometers allow precise determination of weak transitions. A 4(pi) light charged particle detector array of 54 detectors called DIAMANT is described as applied for triggering (gamma)-spectrometers. The multidetector system allows channel...

J. N. Scheurer M. M. Aleonard G. Barreau F. Bourgine J. F. Chemin

1993-01-01

216

An LSO scintillator array for a PET detector module with depth of interaction measurement  

Microsoft Academic Search

Presents construction methods and performance results for a production scintillator array of 64 optically isolated, 3 mm×3 mm×30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8×8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of

J. S. Huber; W. W. Moses; M. S. Andreaco; O. Petterson

2001-01-01

217

Sensitive chiral high-performance liquid chromatographic determination of anthelmintic flubendazole and its phase I metabolites in blood plasma using UV photodiode-array and fluorescence detection Application to pharmacokinetic studies in sheep.  

PubMed

Although benzimidazole anthelmintic flubendazole, methyl ester of [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamic acid, is extensively used in veterinary and human medicine for the treatment of gastrointestinal parasitic helminth infections, reliable data about its pharmacokinetics in various species have not been reported. Our previous work [M. Nobilis, Th. Jira, M. Lísa, M. Holcapek, B. Szotáková, J. Lamka, L.Skálová, J. Chromatogr. A 1149 (2007) 112-120] had described the stereospecificity of carbonyl reduction during phase I metabolic experiments in vitro. For in vivo pharmacokinetic studies, further improvement and optimization of bioanalytical HPLC method in terms of sensitivity and selectivity was necessary. Hence, a modified chiral bioanalytical HPLC method involving both UV photodiode-array and fluorescence detection for the determination of flubendazole, both enantiomers of reduced flubendazole and hydrolyzed flubendazole in the extracts from plasma samples was tested and validated. Albendazole was used as an internal standard. Sample preparation process involved a pH-dependent extraction of the analytes from the blood plasma into tert-butylmethyl ether. Chromatographic separations were performed on a Chiralcel OD-R 250 mm x 4.6mm column with mobile phase methanol-1M NaClO(4) (75:25, v/v) at the flow rate 0.5 ml min(-1). In quantitation, selective UV absorption maxima of 290 nm (for reduced flubendazole), 295 nm (for albendazole), 310 nm (for flubendazole) and 330 nm (for hydrolyzed flubendazole) were used in the UV photodiode-array detection, and lambda(exc.)/lambda(emis.)=228 nm/310 nm (for reduced flubendazole) and lambda(exc.)/lambda(emis.)=236 nm/346 nm (for albendazole) were set on the fluorescence detector. The fluorescence detection was approximately 10-times more sensitive than the UV detection. Each HPLC run lasted 27 min. The validated chiral HPLC-PDA-FL method was employed in the pharmacokinetic studies of flubendazole in sheep. The stereospecificity of the enzymatic carbonyl reduction of flubendazole was also observed in vivo. (+)-Reduced flubendazole was found to be the principal metabolite in ovine blood plasma and only low concentrations of hydrolyzed flubendazole, the parent flubendazole and (-)-reduced flubendazole were detected in this biomatrix. PMID:19004671

Nobilis, Milan; Vybíralová, Zuzana; Krízová, Veronika; Kubícek, Vladimír; Soukupová, Marie; Lamka, Jirí; Szotáková, Barbora; Skálová, Lenka

2008-11-01

218

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

219

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

2010-11-01

220

Modulation transfer function of antenna-coupled infrared detector arrays.  

PubMed

Individual antenna-coupled IR bolometers have recently been demonstrated at wavelengths near 10 ?m. If focal-plane arrays (FPA's) of antenna-coupled detectors can be fabricated, enhancement of IR-imager performance is possible. A first step in the design process is to analyze the image-quality potential of antenna-coupled, FPA-based imagers in terms of the modulation transfer function (MTF). The key step in our analysis is development of a cross-talk MTF that accounts for the electromagnetic coupling between adjacent antennas in the FPA. We find that electromagnetic cross talk will not be a significant image-quality factor in antenna-coupled IR FPA's. PMID:21127627

Boreman, G D; Dogariu, A; Christodoulou, C; Kotter, D

1996-11-01

221

A silicon array detector for high-energy betas  

NASA Astrophysics Data System (ADS)

The detection of significant levels of certain gamma and beta emitting isotopes could allow on-site Inspection teams working under the Comprehensive Test Ban Treaty to localize probable vent and fissure locations. Thus, sophisticated drilling and radionuclide measurements could then be made more effectively allowing for a higher probability of correctly identifying a nuclear event. In order to address this need we have developed a silicon array coupled with a Nal for detecting gammas, high-energy betas, and beta-gamma coincidences. The pursuit of this detection method is now viable since large-area, high-purity silicon wafers are now commercially available making this layered, large-area technique technically and economically feasible. We have designed, constructed, and tested a prototype detector system and we will present out initial test data.

Bowyer, S. M.; Bowyer, T. W.

1999-02-01

222

Electrical breakdown gas detector featuring carbon nanotube array electrodes.  

PubMed

We demonstrate here detection of dichloro-difluoro-methane and oxygen in mixtures with helium using a carbon nanotube electrical breakdown sensor device. The sensor is comprised of an aligned array of multiwalled carbon nanotubes deposited on a nickel based super-alloy (Inconel 600) as the anode; the counter electrode is a planar nickel sheet. By monitoring the electrical breakdown characteristics of oxygen and dichloro-difluoro-methane in a background of helium, we find that the detection limit for dichloro-difluoro-methane is approximately 0.1% and the corresponding limit for oxygen is approximately 1%. A phenomenologigal model is proposed to describe the trends observed in detection of the two mixtures. These results indicate that carbon nanotube based electrical breakdown sensors show potential as end detectors in gas-chromatography devices. PMID:18468093

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

2008-01-01

223

Assessment of reflective separator films for small crystal arrays  

Microsoft Academic Search

Thin, highly reflective, opaque separators are required to assemble compact arrays of small discrete scintillation crystals used in conjunction with photodiode array readouts in high-resolution imaging applications. Mechanical stability, individual detector performance, and ease of handling for wrapping crystals are the main factors to be considered in the choice of a suitable separator. Three different types of reflective materials were

Catherine Michelle Pepin; P. Berard; R. Lecomte

2001-01-01

224

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

Microsoft Academic Search

This paper reports the development of aluminum-gallium nitride (AlGaN or AlxGa1-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

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

2006-01-01

225

Pixel array detectors for time resolved radiography (invited)  

NASA Astrophysics Data System (ADS)

Intense x-ray sources coupled with efficient, high-speed x-ray imagers are opening new possibilities of high-speed time resolved experiments. The silicon pixel array detector (PAD) is an extremely flexible technology which is currently being developed as a fast imager. We describe the architecture of the Cornell PAD, which is capable of operating with submicrosecond frame times. This 100×92 pixel prototype PAD consists of a pixelated silicon diode layer, for direct conversion of the x rays to charge carriers, and a corresponding pixellated complementary metal-oxide-semiconductor electronics layer, for processing and storage of the generated charge. Each pixel diode is solder bump bonded to its own pixel electronics consisting of a charge integration amplifier, an array of eight storage capacitors and an output amplifier. This architecture allows eight complete frames to be stored in rapid succession, with a minimum integration time of 150 ns per frame and an interframe deadtime of 600 ns. We describe the application of the PAD to capture an x-radiograph movie of the mass-density distribution of the spray plume from internal combustion engine fuel injectors.

Renzi, M. J.; Tate, M. W.; Ercan, A.; Gruner, S. M.; Fontes, E.; Powell, C. F.; Macphee, A. G.; Narayanan, S.; Wang, J.; Yue, Y.; Cuenca, R.

2002-03-01

226

Electrochemical imaging of fusion pore openings by electrochemical detector arrays  

PubMed Central

Opening of individual exocytotic fusion pores in chromaffin cells was imaged electrochemically with high time resolution. Electrochemical detector arrays that consist of four platinum microelectrodes were microfabricated on a glass coverslip. Exocytosis of single vesicles containing catecholamines from a cell positioned on top of the array is detected by the individual electrodes as a time-resolved oxidation current, reflecting the time course of arrival of catecholamine molecules at the electrode surfaces. The signals exhibit low noise and reveal foot signals indicating fusion pore formation and expansion. The position of individual release events is determined from the fraction of catecholamines recorded by the individual electrodes. Simultaneous fluorescence imaging of release of acridine orange from individual vesicles confirmed the electrochemical position assignments. This electrochemical camera provides very high time resolution, spatiotemporal localization of individual fusion pore openings and quantitative data on the flux of transmitter from individual vesicles. Analysis of the amperometric currents employing random walk simulations indicates that the time course of amperometric spikes measured near the cell surface is due to a low apparent diffusion coefficient of cat-echolamines near the cell surface and not due to slow dissociation from the granular matrix.

Hafez, Ismail; Kisler, Kassandra; Berberian, Khajak; Dernick, Gregor; Valero, Vicente; Yong, Ming G.; Craighead, Harold G.; Lindau, Manfred

2005-01-01

227

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

SciTech Connect

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

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

2010-06-01

228

Time-dependent photon number discrimination of InGaAs/InP avalanche photodiode single-photon detector.  

PubMed

We investigated the photon-number-resolving (PNR) performance of the InGaAs/InP avalanche photodiode (APD) as a function of the electric gate width and the photon arrival time. The optimal electric gate width was around 1 ns for PNR measurements in our experiment, which provided a PNR capability up to three photons per pulse when the detection efficiency was ~20%. And the dependence of the PNR performance on the arrival time of the photons showed that the photon number could be better resolved if the photons arrived on the rising edge of the electric gate than on the falling edge. In addition, we found that with the increase of the electric gate width, PNR performance got worse. The observation would be helpful for improving the PNR performance of the InGaAs/InP APD in the gated mode. PMID:21221161

Jian, Yi; Wu, E; Chen, Xiuliang; Wu, Guang; Zeng, Heping

2011-01-01

229

Comparison of laboratory and in-flight performance of infared array camera (IRAC) detector arrays on Spitzer Space Telescope  

NASA Astrophysics Data System (ADS)

The Infrared Array Camera (IRAC) on Spitzer Space Telescope includes four Raytheon Vision Systems focal plane arrays, two with InSb detectors, and two with Si:As detectors. A brief comparison of pre- flight laboratory results vs. in-flight performance is given, including quantum efficiency and noise, as well as a discussion of irregular effects, such as residual image performance, "first frame effect", "banding", "column pull-down" and multiplexer bleed. Anomalies not encountered in pre-flight testing, as well as post-flight laboratory tests on these anomalies at the University of Rochester and at NASA Ames using sister parts to the flight arrays, are emphasized.

Pipher, Judith L.; McMurtry, Craig W.; Forrest, William J.; McCreight, Craig R.; McKelvey, Mark E.; McMurray, Robert E., Jr.; Johnson, Roy R.; Fazio, Giovanni G.; Hora, Joseph L.; Allen, Lori E.; Ashby, Matthew L. N.; Barmby, Pauline; Deutsch, Lynne K.; Huang, Jiasheng; Marengo, Massimo; Megeath, S. Thomas; Pahre, Michael A.; Patten, Brian M.; Wang, Zhong; Willner, Steven P.; Hoffmann, William F.; Moseley, Samuel H., Jr.; Arendt, Richard G.; Krebs, Danny J.; Eisenhardt, Peter R.; Stern, Daniel; Gorjian, Varoujan; Bhattacharya, Bidushi; Glaccum, William J.; Lacy, Mark D.; Lowrance, Patrick J.; Carey, Sean J.; Laine, Seppo J.; Stauffer, John R.; Surace, Jason A.; Reach, William T.; Wilson, Gillian

2004-10-01

230

Evaluation of chamber response function influence on IMRT verification using 2D commercial detector arrays  

Microsoft Academic Search

This work is devoted to studying the influence of chamber response functions on the standard IMRT verification for the different detector technologies available on commercial devices. We have tested three of the most used 2D detector arrays for radiotherapy dosimetry verification, based on air-ionization chambers and diode detectors. The response function has been carefully simulated using the Monte Carlo method

A Gago-Arias; L Brualla-González; D M González-Castaño; F Gómez; M Sánchez García; V Luna Vega; J Mosquera Sueiro; J Pardo-Montero

2012-01-01

231

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

232

[Comparison of dose accuracy between 2D array detectors for pre-treatment IMRT QA].  

PubMed

The dosimetric properties between various 2D array detectors were compared and were evaluated with regard to the accuracy in absolute dose and dose distributions for clinical treatment fields. We used to check the dose accuracy: 2D array detectors; MapCHECK (Sun Nuclear), EPID (Varian Medical Systems), EPID-based dosimetry (EPIDose, Sun Nuclear), COMPASS (IBA) and conventional system; EDR2 film (Eastman Kodak), Exradin A-14SL ion chamber (0.016 cc, Standard Imaging). First, we compared the dose linearity, dose rate dependence, and output factor between the 2D array detectors. Next, the accuracy of the absolute dose and dose distributions were evaluated for clinical fields. All detector responses for the dose linear were in agreement within 1%, and the dose rate dependence and output factor agreed within a standard deviation of ±1.2%, except for EPID. This is because EPID is fluence distributions. In all the 2D array detectors, the point dose agreed within 5% with treatment planning system (TPS). Pass rates of each detector for TPS were more than 97% in the gamma analysis (3 mm/3%). EPIDose was in a good agreement with TPS. All 2D array detectors used in this study showed almost the same accuracy for clinical fields. EPIDose has better resolution than other 2D array detectors and thus this is expected for dose distributions with a small field. PMID:22516596

Nakaguchi, Yuji; Araki, Fujio; Saiga, Shunji; Kouno, Tomohiro; Maruyama, Masato; Kakei, Kiyotaka; Nagasue, Nozomu; Hashida, Masahiro

2012-01-01

233

A Prototype Three-Dimensional Position Sensitive CdZnTe Detector Array  

SciTech Connect

A new CdZnTe gamma-ray spectrometer system that employs two layers of modular detector arrays is being developed under the collaboration between the University of Michigan and the Pacific Northwest National Labaratory (PNNL). Each layer can accommodate up to three by three 3-dimensional position sensitive CdZnTe gamma-ray spectrometers. This array system is based on the newly developed VAS_UM/TAT4 ASIC readout electronics. Each of the nine detector modules consists of a pixellated CdZnTe detector and a VAS_UM/TAT4 ASIC frontend board. Each 1.5´1.5´1.0 cm3 CdZnTe detector employs an array of 11 by 11 pixellated anodes and a planar cathode. The energy depositions and 3-dimensional positions of individual interactions of each incident gamma ray can be obtained from pulse amplitude, location of each pixel anode and the drift time of electrons. Ten detectors were tested individually and half of them achieved resolution of <1.0% FWHM at 662 keV for single-pixel events (~30% of all 662 keV full energy deposition events). Two of them were tested in a simple array to verify that the upgrade to an array system does not sacrifice the performance of individual detectors. Experimental results of individual detectors and a twodetector array system are presented, and possible causes for several worse performing detectors are discussed.

Zhang, Feng; He, Zhong; Seifert, Carolyn E.

2007-08-01

234

Determination of 40 synthetic food colors in drinks and candies by high-performance liquid chromatography using a short column with photodiode array detection.  

PubMed

Forty synthetic food colors were determined in drinks and candies by reversed-phase high-performance liquid chromatography with photodiode array detection. The following food colors were analyzed within 19 min using a short analytical column (50 mm x 4.6 mm i.d., 1.8 microm) at 50 degrees C with gradient elution: Ponceau 6R, Tartrazine, Fast yellow AB, Amaranth, Indigotine, Naphthol yellow S, Chrysoine, Ponceau 4R, Sunset yellow FCF, Red 10B, Orange G, Acid violet 7, Brilliant black PN, Allura red AC, Yellow 2G, Red 2G, Uranine, Fast red E, Green S, Ponceau 2R, Azorubine, Orange I, Quinoline yellow, Martius yellow, Ponceau SX, Ponceau 3R, Fast green FCF, Eosine, Brilliant blue FCF, Orange II, Orange RN, Acid blue 1, Erythrosine, Amido black 10B, Acid red 52, Patent blue V, Acid green 9, Phloxine B, Benzyl violet 4B, and Rose bengal. The recoveries of these compounds added to soft drinks and candies at 5 microg/g ranged from 76.6 to 115.0%, and relative standard deviations (R.S.D.s) were within 6.0%. The limits of detection and the limits of quantitation were 0.03 and 0.1 microg/g, respectively. PMID:18371797

Yoshioka, N; Ichihashi, K

2007-09-26

235

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

236

Analysis of manufacturing by-products and impurities in illicit cocaine via high-performance liquid chromatography and photodiode array detection.  

PubMed

An high-performance liquid chromatography (HPLC) method is reported for the detection of manufacturing by-products and impurities in illicitly produced cocaine. For the first time peak enriched chromatograms were obtained using HPLC, and were accomplished using reversed-phase chromatography and photodiode array detection. The use of sodium dodecylsulfate as an ion-pairing reagent permitted the simultaneous separation of acids, mono-protic amines and di-protic amines, and, in combination with gradient elution, greatly increased the number of compounds separated. A mixed binary-ternary gradient was used to further optimize the separation. Dual UV detection at 215 and 277 nm was used. The chromatogram at 215 nm consisted first of carboxylic acids such as benzoic acid, cinnamic acid (cis and trans) and several isomers of truxillic and truxinic acid; next the mono-protic amines benzoylecgonine and cinnamoylcocaine (cis and trans); and last a group of compounds which are believed to be isomers of the di-protic amine truxilline. In addition, simultaneous detection at 277 nm permitted the selective detection of various compounds, some of which are additional components. The rapid acquisition of UV spectra greatly facilitated compound identification. PMID:3693467

Lurie, I S; Moore, J M; Cooper, D A; Kram, T C

1987-09-18

237

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

2012-04-20

238

Avalanche photodiode  

US Patent & Trademark Office Database

An avalanche photodiode having an absorption zone, a multiplication zone, and a transition zone disposed between the absorption zone and the multiplication zone, the transition zone being doped and being constituted at least in part by a material of composition that is graded such that the energy bands of the structure are substantially continuous when it is biased, wherein said doping is distributed non-uniformly in said graded composition zone so as to compensate, at least in part, the reverse electric field due to the composition grading of the material in the transition zone.

1999-06-15

239

Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration  

Microsoft Academic Search

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

Frode Ringdal; D B Harris; D Dodge; S J Gibbons

2009-01-01

240

Very large arrays of flip-chip bonded 1.55-?m photodiodes for spectroscopic monitoring of WDM networks  

Microsoft Academic Search

We have demonstrated and analyzed very large arrays of flip-chip bonded InGaAs\\/InP photodetectors, in particular paying attention to how their series and shunt resistances affect zero-bias photocurrent and therefore yield for spectrometer applications. Our device design results in very low series resistance of the diode and high photocurrent collection efficiency at zero-bias. It was shown that for an integrated circuit

K. W. Goossen; J. E. Cunningham; G. Zhang; J. A. Walker

1998-01-01

241

Construction of a large scale integration circuit equipped with an IR detector array and electronic multiplexing  

NASA Astrophysics Data System (ADS)

The design and construction of a circuit containing an array of four infrared detectors is described. The circuit is part of a MultiProject Chip built at Lindkopings Technical University. Schematics and circuit diagrams are presented.

Helgodt, R.; Nilsson, B.; Pettersson, H.

1981-09-01

242

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

SciTech Connect

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

Amenomori, M.; Nanjo, H. [Department of Physics, Hirosaki University, Hirosaki 036-8561 (Japan); Bi, X. J.; Ding, L. K.; Feng, Zhaoyang; He, H. H.; Hu, H. B.; Lu, H.; Lu, S. L.; Ren, J. R.; Tan, Y. H.; Wang, B.; Wang, H.; Wang, Y.; Wu, H. R.; Zhang, H. M.; Zhang, J. L.; Zhang, Y. [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, D.; Kawata, K. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)] (and others)

2008-12-24

243

Far-IR linear detector array for DARWIN  

NASA Astrophysics Data System (ADS)

Acreo is one of the leading producers of QWIP FPAs in the world and is also intensively running R&D activities. In the frames of the European Space Agency’s (ESA) Darwin mission, Acreo has been awarded the contract “Far-IR Linear Detector Array for Darwin” in the mid- and long-infrared (4 20 ?m) wavelength band. It has been proven that QWIP material could be tailored to be sensitive to different wavelengths [S. Bandara, S. Gunapala, S. Rafol, D. Ting, J. Liu, J. Mumolo, T. Trinh, A.W.K. Liu, J.M. Fastenau, Quantum well infrared photodetectors for low background applications, Infrared Phys. Technol. 42 (2001) 237]. The goal of the awarded contract is to establish and demonstrate the ultimate performance of Acreo’s QWIP-technology for this application at the highest operating temperature possible. For this purpose Acreo has designed and grown several samples of QWIP material sensitive to different wavelengths in the range of 6 18 ?m. The grown structures were optically and electrically characterized. The Darwin mission imposes extremely hard requirements on dark current. The QWIP structures with low dark current have reduced absorption coefficient. The project is targeted at finding the optimal trade-off between the total quantum efficiency, dark current and operating temperature. Detailed analysis of the dark current components with emphasis on low operating temperature was carried out. Special attention is paid to the optimization of optical coupling in order to preserve the required level of the quantum efficiency while reducing dark current. This paper presents the latest results from this project.

Martijn, Henk; Gromov, Andrey; Smuk, Sergiy; Malm, Hedda; Asplund, Carl; Borglind, Jan; Becanovic, Smilja; Alverbro, Jörgen; Halldin, Urban; Hirschauer, Bernhard

2005-10-01

244

A charged particle detector array for detection of light charged particles from nuclear reactions  

NASA Astrophysics Data System (ADS)

A 4? charged particle detector array (CPDA), for detecting low-Z charged particles from nuclear reactions, was built to improve selection of fusion evaporation channels for in-beam gamma spectroscopy measurements at Inter University Accelerator Centre, New Delhi. The array consists of fourteen fast–slow plastic phoswich detectors coupled to photomultiplier tubes through indigenously developed optical light guides. This paper describes design of optical light guide, target chamber, front-end electronics and presents in-beam performance of the array. Custom made analogue electronic device enables online selection of nuclear reaction channel. The charged particle detection efficiency and improvement in peak to background ratio obtained using CPDA in conjunction with a gamma-detector array demonstrates its usefulness in selection of specific nuclear reaction channel. This array has been used in a number of nuclear spectroscopic and reaction investigations.

Muralithar, S.; Mukherjee, B.; Singh, R. P.; Mukherjee, G.; Joshi, P.; Punithan, A.; Sahu, B. K.; Gupta, A.; Ahuja, R.; Ram, R.; Rao, S.; Saini, S. K.; Zacharis, J.; Bhowmik, R. K.

2013-11-01

245

Read-Noise Characterization of Focal Plane Array Detectors via Mean-Variance Analysis  

SciTech Connect

Mean-variance analysis is described as a method for characterization of the read-noise and gain of Focal Plane Array (FPA) detectors, including CCDs, CIDs, and CMOS multiplexers (IR arrays). Practical FPA detector characterization is outlined. The non-destructive readout capability available in some FPA devices is discussed as a means for signal-to-noise ratio improvement. Derivations of the equations are fully presented to unify understanding of this method by the spectroscopic community.

Sperline, Roger P.; Knight, Andrew K.; Gresham, Christopher A.; Koppenaal, David W.; Hieftje, Gary M.; Denton, M Bonner B.

2005-11-01

246

From Ge(Li) detectors to gamma-ray tracking arrays 50 years of gamma spectroscopy with germanium detectors  

NASA Astrophysics Data System (ADS)

The structure of the atomic nucleus has been studied to a large extent by gamma-ray spectroscopy using germanium (Ge) detectors. Ge detectors were developed in the 1960s and still offer the best compromise between energy resolution and efficiency for high-resolution gamma-ray spectroscopy. In the 1970s and 1980s the main advances were in the purity and volume of the Ge crystals. More recently the development of highly-segmented Ge detectors has significantly increased the performance and power of detection systems. In a segmented Ge detector the crystal is divided into sections by isolating the contacts. This enables the position of interaction to be determined. The accuracy of the position determination can be improved by the analysis of the shape of the charge signals and of the transient signals in adjacent segments. This technique has led to the concept of gamma-ray tracking in a segmented Ge detector whereby the energy, time and position of all interactions are recorded and the full interaction is reconstructed. This enables a spectrometer system with unprecedented efficiency and energy resolution to be realized. In this article, the history of Ge detectors and Ge detector arrays for nuclear spectroscopy will be reviewed. The technology and properties of highly-segmented coaxial Ge detectors as developed for the European ?-ray tracking array AGATA will be highlighted.

Eberth, J.; Simpson, J.

2008-04-01

247

Studies on the fabrication method for the array of polycrystalline mercuric iodide detectors  

NASA Astrophysics Data System (ADS)

The Mercuric Iodide (HgI2) semiconductor array detectors possess the characters of low noise, high detection efficiency, high energy resolution and working in room temperature. In this work, modified hot-wall physical vapor deposition (HW-PVD) method was used to grow high-quality polycrystalline HgI2 thin-films on ITO glasses, and then 4×4 and 8×8 HgI2 array detectors for X-ray radiation were fabricated. We used two fabrication processes for polycrystalline HgI2 array detectors. One was using mask made of stainless steel with good flexibility; while the other was to photo lithography the array on the ITO glass. The main purpose for this work was to compare the electrical properties of polycrystalline HgI2 array detectors fabricated from different processes, and to find out the optimal process for HgI2 detectors. Results indicated that the photo lithography method was a better way to fabricate polycrystalline mercuric iodide array detector than using mask method.

Zheng, Wei-Feng; Shi, Wei-Min; Li, Dong-Mei; Qin, Juan; Wang, Lin-Jun; Huang, Jian; Yu, Jun-Yang; Xia, Yi-Ben

2009-07-01

248

Design and performance of a cesium iodide detector  

NASA Astrophysics Data System (ADS)

The design, construction, and performance of a 198-element CsI detector built for Brookhaven experiment E852 is described. Design considerations for the array included such factors as rate, magnetic field, sensitivity and acceptance. Signals were obtained with a photodiode/preamplifier combination using PIN photodiodes. Data were taken over the course of two runs during the summers of 1993 and 1994. A calibration procedure using halo muons is described. The gain, energy resolution, and position resolution of the detector are discussed. Finally, the ability of the detector to be used as a low energy photon veto is illustrated using the data.

Adams, T.; Bishop, J. M.; Cady, R.; Cason, N. M.; Gress, J.; Kopp, C.; Losecco, J. M.; Manak, J. J.; Sanjari, A. H.; Shephard, W. D.; Stienike, D. L.; Taegar, S. A.; Thompson, D. R.; U. Chung, S.; Hackenburg, R. W.; Olchanski, C.; Weygand, D. P.; Willutzki, H. J.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Shein, I.; Soldatov, A.; Brabson, B. B.; Crittenden, R. R.; Dzierba, A. R.; Gunter, J.; Lindenbusch, R.; Rust, D. R.; Scott, E.; Smith, P. T.; Sulanke, T.; Teige, S.; Bar-Yam, Z.; Dowd, J. P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Bodyagin, V. A.; Gribushin, A. M.; Kostin, M. A.; Korotkikh, V. L.; Ostrovidov, A. I.; Proskuryakov, A. S.; Sarycheva, L. I.; Sinev, N. B.; Vardanyan, I. N.; Yershov, A. A.; Brown, D. S.; Pedlar, T. K.; Seth, K. K.; Wise, J.; Zhao, D.; Adams, G. S.; Napolitano, J.; Nozar, M.; Smith, J. A.; Witkowski, M.

1996-02-01

249

Development of 30 Micrometers Extrinsic Silicon Multiplexed Infrared Detector Array. Final Report, March 1985-June 1986.  

National Technical Information Service (NTIS)

Two hybrid infrared (IR) detector arrays of antimony-doped silicon (Si:Sb) were produced and tested to evaluate their potential for use in low-background IR astronomy applications. The format of the arrays is 58 x 62 elements, with 76 micron-square pixels...

G. Orias D. Campbell

1986-01-01

250

A biologically inspired compound-eye detector array part II: Statistical performance analysis  

Microsoft Academic Search

This is the second part of our paper. In this paper, we propose, model, and analyze the performance of a detector array for localizing far-field particle-emitting sources, which is inspired by but generalizes the compound eye of insects. The array consists of multiple eyelets, each having a conical module with a lens on its top and an inner subarray containing

Zhi Liu; Arye Nehorai; Eytan Paldi

2009-01-01

251

Smart-Optical Detector CMOS Array for Biochemical Parameters Analysis in Physiological Fluids  

Microsoft Academic Search

This paper describes the implementation of a smart-optical detector array for detection and concentration measurement of biochemical parameters in physiological fluids. Its application is in the low-cost microchip size analytical laboratories that use colorimetric detection, by optical absorption, as the analytical technique. The microlaboratory structure is composed of a microplate cuvette array containing the physiological fluids into analysis and an

A. V. Fernandes; V. F. Cardoso; J. G. Rocha; J. Cabral; GraÇa Minas

2008-01-01

252

Five-channel, diamond photoconducting x-ray detector array for z- pinch experiments.  

National Technical Information Service (NTIS)

We have built a five-channel, x-ray detector array based on diamond photoconducting detectors (PCDs). The diamond elements have dimensions of 3 mm times 1 mm times 1 mm (or 0.5 mm). We use PCDs for their stability, flat spectral response, and low leakage ...

R. B. Spielman

1992-01-01

253

Development of material quality and structural design for high performance Type II InAs/GaSb superlattice photodiodes and focal plane arrays  

NASA Astrophysics Data System (ADS)

Recent progress made in the structure design, growth and processing of Type-II InAs/GaSb superlattice photo-detectors lifted both the quantum efficiency and the R0A product of the detectors. Type-II superlattice demonstrated its ability to perform imaging in the Mid-Wave Infrared (MWIR) and Long-Wave Infrared (LWIR) ranges, becoming a potential competitor for technologies such as Quantum Well Infrared Photo-detectors (QWIP) and Mercury Cadmium Telluride (MCT). Using an empirical tight-binding model, we developed superlattices designs that were nearly lattice-matched to the GaSb substrates and presented cutoff wavelengths of 5 and 11 ?m. We demonstrated high quality material growth with X-ray FWHM below 30 arcsec and an AFM rms roughness of 1.5 Å over an area of 20x20 ?m2. The detectors with a 5 ?m cutoff, capable of operating at room temperature, showed a R0A of 1.25 106 ?.cm2 at 77K, and a quantum efficiency of 32%. In the long wavelength infrared, we demonstrated high quantum efficiencies above 50% with high R0A products of 12 ?.cm2 by increasing the thickness of the active region. Using the novel M-structure superlattice design, more than one order of magnitude improvement has been observed for electrical performance of the devices. Focal plane arrays in the middle and long infrared range, hybridized to an Indigo read out integrated circuit, exhibited high quality imaging.

Razeghi, Manijeh; Nguyen, Binh-Minh; Hoffman, Darin; Delaunay, Pierre-Yves; Huang, Edward Kwei-wei; Tidrow, Meimei; Nathan, Vaidya

2008-08-01

254

Development of a Versatile Array of Neutron Detectors at Low Energy  

SciTech Connect

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new array of plastic scintillator bars under development for measurements at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The array is highly modular allowing the configuration of the individual elements to be optimized for particular experimental requirements, such as (d,n) and beta-delayed neutron-decay measurements with neutron-rich rare isotope beams.

Matei, C. [Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Bardayan, D. W. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Blackmon, J. C. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge LA 70803 (United States); Cizewski, J. A.; Peters, W. A. [Department of Physics and Astronomy, Rutgers University, New Brunswick NJ 08903 (United States); Grzywacz, R. K.; Liddick, S. N.; Padgett, S. W. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Sarazin, F. [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States)

2009-03-10

255

Development of a Versatile Array of Neutron Detectors at Low Energy  

SciTech Connect

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new array of plastic scintillator bars under development for measurements at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The array is highly modular allowing the configuration of the individual elements to be optimized for particular experimental requirements, such as (d,n) and beta-delayed neutron-decay measurements with neutron-rich rare isotope beams.

Matei, Catalin [Oak Ridge Associated Universities (ORAU); Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Cizewski, J. A. [Rutgers University; Grzywacz, R. K. [University of Tennessee; Liddick, Sean [University of Tennessee, Knoxville (UTK); Padgett, S. [University of Tennessee; Peters, W. A. [Rutgers University; Sarazin, F. [Colorado School of Mines, Golden

2009-04-01

256

Distributed Antenna-Coupled TES for FIR Detector Arrays  

Microsoft Academic Search

We report progress toward large arrays of sensitive TES bolometers for submillimeter and far-infrared wavelengths with noise\\u000a equivalent power (NEP) suitable for either imaging from a cooled space telescope or ground based spectroscopy. The arrays\\u000a are based on a pixel design that makes use of a distributed transition edge sensor (TES) coupled to a slot antenna array.\\u000a We have electrically

P. Day; H. G. Leduc; C. D. Dowell; R. A. Lee; A. Turner; J. Zmuidzinas

2008-01-01

257

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

Microsoft Academic Search

Operating characteristics of the Indiana Silicon Sphere 4 pi detector array are outlined. The detector geometry is spherical, with 90 telescopes in the forward hemisphere and 72 at backward angles, covering a total solid angle of 74% of 4pi. Each telescope consists of a simple gas-ion chamber, operated with C3F8 gas, followed by a 0.5 mm thick ion-implanted silicon detector

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

1994-01-01

258

Marine seismic streamer cable for providing selectable detector array connections  

SciTech Connect

A marine seismic cable comprising a plurality of universal sections, each section including a plurality of fundamental arrays, preferably positioned end-to-end. Each of the arrays are separately wired to a logic circuit in one of the connectors or cans between sections and wiring is provided for connections to each of the fundamental arrays in at least an adjoining section. The logic circuits are controlled by control signals to produce composite responses from a selected grouping of fundamental arrays and, preferably, also to produce weighted or tapered responses by connecting and emphasizing each of the fundamental responses in the desired weighted manner.

Steetle, D. R.

1985-08-27

259

First tests of a fission-tagging detector for the DANCE array  

NASA Astrophysics Data System (ADS)

A proof-of-principle experiment has been performed with the DANCE 4? BaF2 array to explore the feasibility of adding a fission-tagging detector. The initial tests utilized a deposit of ^235U on a solar cell, which was used to detect the fission fragments, while ?-rays were measured by the DANCE array. The addition of a fission-tagging detector to the DANCE array will provide a means to study several important issues associated with neutron induced fission, including (n,fission) cross sections as a function of incident neutron energy, and total energy and multiplicity of prompt fission photons.

Bredeweg, T. A.; Ethvignot, T.; Wilhelmy, J. B.; Esch, E.-I.; Granier, T.; Haight, R. C.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.

2004-10-01

260

Ultrahigh sensitivity single-photon detector using a Si avalanche photodiode for the measurement of ultraweak biochemiluminescence  

NASA Astrophysics Data System (ADS)

This paper demonstrates that very high sensitivity on the order of 10(sup -19) W is achievable even with a single-photon detector using a nonselected sample of a commercially available Si APD for optical communication by cooling to liquid nitrogen temperature and optimizing the operating condition. The application of this system to the measurement of ultraweak biochemiluminescence on the order of 10(sup -19) W/mm(sup 2) from a cultured hippocampal slice consisting of neural and glial cells has been described. This is the first demonstration of availability of the APD photon counter to the ultraweak biochemiluminescence from a cultured cell group rather than the whole organism or homogenized tissue.

Isoshima, Takashi; Isojima, Yasushi; Hakomori, Katsuhiko; Kikuchi, Kazuro; Nagai, Katsuya; Nakagawa, Hachiro

1995-04-01

261

Waveguide biosensor with integrated detector array for tuberculosis testing  

Microsoft Academic Search

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

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

2011-01-01

262

Lead chalcogenides based IR photosensitive array detectors with coordinate addressing  

Microsoft Academic Search

Coordinate addressed photodetector arrays based on thin films of lead chalcogenides and operating in different wavebands of the infrared spectral regions are described. The arrays feature high sensitivity, close to BLIP mode, wide dynamic range, and low heat dissipation. Their advantages include random access, element block selection, image scaling, and on chip data encoding. Different design configurations with elements from

G. A. Agranov; S. K. Novoselov; R. M. Stepanov; A. Z. Doon; A. V. Pashkevich; A. I. Ivanov; I. K. Nemchuk; V. K. Nesterov; V. E. Skoriukin

1992-01-01

263

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

264

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

NASA Astrophysics Data System (ADS)

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

Abraham, J.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Anti?i?, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arisaka, K.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avila, G.; Bäcker, T.; Badagnani, D.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Barroso, S. L. C.; Baughman, B.; Bauleo, P.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; Benzvi, S.; Berat, C.; Bergmann, T.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; 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.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Colombo, E.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Domenico, M.; de Donato, C.; de Jong, S. J.; de La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; de Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; Del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Duvernois, M. A.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrero, A.; Fick, B.; Filevich, A.; Filip?i?, A.; Fleck, I.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fulgione, W.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Goggin, L. M.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hague, J. D.; Halenka, V.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Hussain, M.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Jiraskova, S.; Kadija, K.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D.-H.; Krieger, A.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, K.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Lee, J.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McEwen, M.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Meurer, C.; Mi?anovi?, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Mueller, S.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parlati, S.; Parra, A.; Parrisius, J.; Parsons, R. D.; Pastor, S.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Pe?ala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Ravel, O.

2010-01-01

265

Using CORSIKA to quantify Telescope Array surface detector response  

Microsoft Academic Search

Historically, studies of surface detector response have been severely limited by the inability to simulate charge density fluctuations at the distance scale of individual detector units. We present a two- prong solution. First, we have developed an interface script that allows us to simulate a cosmic ray shower, using CORSIKA, that runs in parallel on many computers simultaneously. In doing

B. T. Stokes; R. Cady; D. Ivanov; G. B. Thomson; G. I. Rubtsov

266

Development of segmented Ge detectors for future ?-ray arrays  

NASA Astrophysics Data System (ADS)

The EUROBALL Cluster detector is composed of seven encapsulated Ge detectors in a common cryostat with a total volume of 2000 ccm of HP Gemanium. The development and the performance of the Cluster detector is summarized. Up to six Cluster detectors were used in pre-EUROBALL experiments at the S-DALINAC Darmstadt, at the tandem-postaccelerator facility of the MPI-K Heidelberg and at the UNILAC at GSI. Examples of these experiments - the excitation of dipole modes with (?, ?')-reactions and the first coincidence spectroscopy of the N=Z-nucleus 68Se with a CLUSTER Cube - are discussed. The development of segmented encapsulated Ge detectors for a MINIBALL at the radioactive beam facility REX-ISOLDE has been launched. The status of the project is presented.

Eberth, J.; Thomas, H. G.; Weisshaar, D.; Becker, F.; Fiedler, B.; Skoda, S.; von Brentano, P.; Gund, C.; Palafox, L.; Reiter, P.; Schwalm, D.; Habs, D.; Servene, T.; Schwengner, R.; Schnare, H.; Schulze, W.; Prade, H.; Winter, G.; Jungclaus, A.; Lingk, C.; Teich, C.; Lieb, K. P.

267

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

268

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

269

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

270

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

271

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.

1984-02-01

272

CdTe Array Detectors for High Energy Astronomy.  

National Technical Information Service (NTIS)

The results of missions such as SIGMA and CGRO have convincingly demonstrated the need for fine spectroscopy and imaging in high energy astronomy. A possible answer to these requirements could be offered by Position Sensitive Detectors (PSD) based on modu...

E. Caroli G. Baldazzi G. Dicocco A. Donati W. Dusi

1992-01-01

273

Sensor modelling for the Cyclops focal plane detector array based technology demonstrator  

NASA Astrophysics Data System (ADS)

The Surveillance Research Laboratory of the DSTO has developed a technology demonstrator utilizing an infrared focal plane detector array to assess the feasibility of using large scale infrared detector arrays for ADF applications. The imaging sensor which has been developed requires no scanning mechanism and uses an array of mercury cadmium telluride detectors sensitive to radiation in the 8 um to 12 um spectral region to produce an image. The sensor was tested in a series of airborne trails and the results obtained from these trials will be used to evaluate the performance of focal plane detector array based systems. A mathematical model of the sensor has been used to evaluate the performance of the sensor. The mathematical model has been developed to meet the requirements imposed by analysis of the performance of this sensor. The model is based on the description of the operation of the elements of the detector array as photon counters. A description of the model used for the analysis of the data obtained using the sensor is presented here.

Poropat, G. V.

1992-12-01

274

Semiconductor detectors and focal plane arrays for far-infrared imaging  

NASA Astrophysics Data System (ADS)

The detection of far-infrared (far-IR) and sub-mm-wave radiation is resistant to the commonly employed techniques in the neighbouring microwave and IR frequency bands. In this wavelength detection range the use of solid state detectors has been hampered for the reasons of transit time of charge carriers being larger than the time of one oscillation period of radiation. Also the energy of radiation quanta is substantially smaller than the thermal energy at room temperature and even liquid nitrogen temperature. The realization of terahertz (THz) emitters and receivers is a challenge because the frequencies are too high for conventional electronics and the photon energies are too small for classical optics. Development of semiconductor focal plane arrays started in seventies last century and has revolutionized imaging systems in the next decades. This paper presents progress in far-IR and sub-mm-wave semiconductor detector technology of focal plane arrays during the past twenty years. Special attention is given on recent progress in the detector technologies for real-time uncooled THz focal plane arrays such as Schottky barrier arrays, field-effect transistor detectors, and microbolometers. Also cryogenically cooled silicon and germanium extrinsic photoconductor arrays, and semiconductor bolometer arrays are considered.

Rogalski, A.

2013-09-01

275

The design of linear and quasi-linear CCD detectors and detector arrays to meet system performance requirements  

NASA Astrophysics Data System (ADS)

Specifications for detector/array designs based on system performance requirements and device design rules are described. The use of time delay and integration (TDI) detectors to increase exposure time without lengthening the line-scan interval is examined; the advantages and disadvantages of the TDI imager are discussed. Design rules for developing imagers are based on providing the maximum amount of signal/pixel. The effects of the integrated and spectral responsitivity of the imager, pixel size, pixel count/channel of readout, charge capacity, the modulation transfer function, crosstalk, the S/N ratio, and exposure time on the performance and utility of a chip are investigated.

Wight, Ralph

1986-01-01

276

MAJORANA: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements  

NASA Astrophysics Data System (ADS)

The Majorana collaboration aims to perform a search for neutrinoless double-beta decay (0???) by fielding arrays of HPGe detectors mounted in ultra-clean electroformed-copper cryostats located deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, show great promise for identifying and reducing backgrounds to the 0??? signal, which should result in improved sensitivity over previous generation experiments. The ultra-low energy threshold possible in PPC detectors also enables a broader physics program including sensitive searches for dark matter and axions. The Majorana Demonstrator R&D program will field three ˜20 kg modules of PPC detectors at Sanford Underground Laboratory. Half of the detector mass will be enriched to 86% in ^76Ge. I will present the motivation, design, recent progress and current status of this R&D effort, and discuss its physics reach.

Detwiler, Jason

2009-10-01

277

Majorana: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements  

NASA Astrophysics Data System (ADS)

The Majorana collaboration will search for neutrinoless double-beta decay (0???) by fielding an array of high-purity germanium (HPGe) detectors in ultra-clean electroformed-copper cryostats deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, present exciting new techniques for identifying and reducing backgrounds to the 0???. This should result in greatly improved sensitivity over previous generation experiments. The exceptionally low energy threshold attainable with PPC detectors also enables a broad physics program including searches for dark matter and axions. The Majorana Demonstrator is an R&D program that will field two ˜20 kg modules of PPC detectors at Sanford Underground Laboratory. Approximatly half of the detectors will be enriched to 86% in ^76Ge. Here, we will cover the motivation, design, recent progress and current status of this effort, with special attention to its physics reach.

Miller, Michael

2010-11-01

278

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

NASA Astrophysics Data System (ADS)

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

Jaggi, S.

1991-11-01

279

Search for ultra-high energy photons and neutrinos using Telescope Array surface detector  

NASA Astrophysics Data System (ADS)

We search for ultra-high energy photons by analyzing geometrical properties of shower fronts of events registered by the Telescope Array surface detector. By making use of an event-by-event statistical method, we derive upper limits on the absolute flux of primary photons with energies above 1019eV, 1019.5eV and above 1020eV based on the three years data from Telescope Array surface detector (May 2008 - May 2011). We report the results of down-going neutrino search based on the analysis of very inclined events.

Rubtsov, G. I.; Fukushima, M.; Ivanov, D.; Stokes, B. T.; Thomson, G. B.; Troitsky, S. V.

2013-06-01

280

Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array  

SciTech Connect

Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.

2010-06-29

281

Spatial resolution of SCD's InSb 2D detector arrays  

NASA Astrophysics Data System (ADS)

The two-dimensional spatial response of a pixel in SCD's back-side illuminated InSb Focal Plane Array (FPA) is measured directly for arrays with a small pitch, namely 30, 20 and 15?m. The characterization method uses a spot-scan measurement and de-convolution algorithm to obtain the net spatial response of a pixel. Two independent methods are used to measure the detector spatial response: a) direct spot-scan of a pixel with a focused beam; b) uniform illumination upon back-side evaporated thin gold coating, in which sub-pixel apertures are distributed in precise positions across the array. The experimental results are compared to a 3D numerical simulation with excellent agreement for all pitch dimensions. The spatial response is used to calculate the crosstalk and the Modulation Transfer Function (MTF) of the pixel. We find that for all three pixel dimensions, the net spatial response width (FWHM) is equal to the pitch, and the MTF width is inversely proportional to the pitch. Thus, the spatial resolution of the detector improves with decreasing pixel size as expected. Moreover, for a given optics and smaller array pitch, the overall system spatial resolution is limited more by the optical diffraction than by the detector. We show actual improved spatial resolution in an imaging system with a detector of smaller array pitch.

Shtrichman, Itay; Fishman, Tal; Mizrahi, Udi; Nahum, Vered; Calahorra, Zippora; Aron, Yoram

2007-05-01

282

Submillimeter resolution PET detector module using Multi-Pixel Photon Counter array  

Microsoft Academic Search

The aim of this study is to design a novel PET detector module using an array of sub-millimeter LSO crystal read out by an array of surface-mount type of Multi-Pixel Photon Counter (MPPC). The volume of one MPPC sensor is 2.4 × 1.9 × 0.8 mm3 and the sensitive area is 1 × 1 mm2. The 9 MPPCs were arranged

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

2008-01-01

283

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

284

CdZnTe detector array for a scanning-beam digital x-ray system  

Microsoft Academic Search

The Scanning-Beam Digital X-ray (SBDX) system promises low-dose cardiac fluoroscopy and angiography with excellent image quality. The system demands a detector capable of high count rates and excellent detection efficiency. Cadmium zinc telluride (CdZnTe) is well suited to these requirements. The SBDX detector comprises sixteen 3-mm-thick, 13.5 mm x 13.5 mm tiles arranged in a 4x4 array. Each tile has

Joseph A. Heanue; David A. Pearson; Robert E. Melen

1999-01-01

285

CdZnTe detector array for a scanning-beam digital x-ray system  

Microsoft Academic Search

The Scanning-Beam Digital X-ray (SBDX) system promises low- dose cardiac fluoroscopy and angiography with excellent image quality. The system demands a detector capable of high count rates and excellent detection efficiency. Cadmium zinc telluride (CdZnTe) is well suited to these requirements. The SBDX detector comprises sixteen 3-mm-thick, 13.5 mm X 13.5 mm tiles arranged in a 4 X 4 array.

Joseph A. Heanue; David A. Pearson; Robert E. Melen

1999-01-01

286

Photoresponse of a miniaturized ultrabroad-band low-noise metal-film bolometer detector array  

Microsoft Academic Search

A miniaturized low-noise metal-film bolometer detector array capable of recording radiation spanning a wide spectral range is presented. The bolometers consist of structured gold layers coated with a black nickel layer to reduce the reflectivity in the long-wavelength range. Investigation of the device`s photoresponse showed sufficient sensitivity at wavelengths lambda =4 mm to 6 AA. The detector unit meets high-vacuum

P. T. Lang; K. F. Mast

1996-01-01

287

Testing the Large-area multi-Institutional Scintillator Array (LISA) Neutron Detector  

Microsoft Academic Search

The 144 detector modules comprising the Large-area multi-Institutional Scintillator Array (LISA) neutron detector were tested at each of the nine primarily undergraduate institutions. Each module is a 200 cm by 10 cm by 10 cm bar of EJ-200 organic plastic scintillator a with a photomultiplier tube mounted on each end. We used cosmic rays both to ensure that each module

T. B. Nagi; K. M. Rethman; K. A. Purtell; A. J. Haagsma; C. Deroo; M. Jacobson; S. Kuhn; A. R. Peters; M. Ndong; S. A. Stewart; Z. Torstrick; R. Anthony; H. Chen; A. Howe; N. S. Badger; M. D. Miller; B. J. Foster; L. C. Rice; C. Vest; A. B. Aulie; A. Grovom; L. Elliot; P. Kasavan

2010-01-01

288

Adaptive non-uniformity correction method based on temperature for infrared detector array  

NASA Astrophysics Data System (ADS)

The existence of non-uniformities in the responsitivity of the element array is a severe problem typical to common infrared detector. These non-uniformities result in a "curtain'' like fixed pattern noises (FPN) that appear in the image. Some random noise can be restrained by the method kind of equalization method. But the fixed pattern noise can only be removed by .non uniformity correction method. The produce of non uniformities of detector array is the combined action of infrared detector array, readout circuit, semiconductor device performance, the amplifier circuit and optical system. Conventional linear correction techniques require costly recalibration due to the drift of the detector or changes in temperature. Therefore, an adaptive non-uniformity method is needed to solve this problem. A lot factors including detectors and environment conditions variety are considered to analyze and conduct the cause of detector drift. Several experiments are designed to verify the guess. Based on the experiments, an adaptive non-uniformity correction method is put forward in this paper. The strength of this method lies in its simplicity and low computational complexity. Extensive experimental results demonstrate the disadvantage of traditional non-uniformity correct method is conquered by the proposed scheme.

Zhang, Zhijie; Yue, Song; Hong, Pu; Jia, Guowei; Lei, Bo

2013-09-01

289

Diode Characterization of Rockwell LWIR HgCdTe Detector Arrays  

NASA Astrophysics Data System (ADS)

Future infrared space missions will undoubtedly employ passively cooled focal planes (T ~ 30K), as well as passively cooled telescopes. Most long-wave detector arrays (e.g. Si:As IBC) require cooling to temperatures of ~ 6-8K. We have been working with Rockwell to produce 10?m cutoff HgCdTe detector arrays that, at temperatures of ~ 30K, exhibit sufficiently low dark current and sufficiently high detective quantum efficiency to be interesting for astronomy. In pursuit of these goals, Rockwell Scientific Company has delivered twelve 256 x 256 arrays (several of them engineering arrays), with cutoff wavelengths at 30K between 7.4 and 11?m for characterization at Rochester. Seven of these arrays utilize advanced structure diodes with differing capacitances arranged in rows (banded arrays), and the materials properties of the HgCdTe also vary significantly from array to array. Of ultimate interest to astronomy is the fraction of pixels with dark current below the target value of ~ 100e-/s with 10-60mV of actual reverse bias across the diodes at T ~ 30K. These arrays were developed for the purpose of selecting diode architecture: we use this fraction as one criterion for selection. We have determined from these experiments the optimal diode architecture for future array development. Measurement of the dark current as a function of reverse bias and temperature allows us to ascertain the extent to which trap-to-band tunneling dominates the dark current at this temperature. We present the results for one representative array, UR008.

Bacon, Candice; Pipher, Judith L.; Forrest, William J.; McMurtry, Craig W.; Garnett, James D.

2003-03-01

290

Optochemical sensor based on screenprinted fluorescent sensorspots surrounded by organic photodiodes for multianalyte detection  

NASA Astrophysics Data System (ADS)

A compact, integrated photoluminescence based oxygen sensor, utilizing an organic light emitting device (OLED) as the light source and an organic photodiode (OPD) as the detection unit, is described. The detection system of the sensor array consists of an array of circular screen-printed fluorescent sensor spots surrounded by organic photodiodes as integrated fluorescence detectors. The OPD originates from the well-known Tang photodiode, consisting of a stacked layer of copper phthalocyanine (CuPc, p-type material) and perylene tetracarboxylic bisbenzimidazole (PTCBi, n-type material). An additional layer of tris-8-hydroxyquinolinatoaluminium (Alq3, n-type material) was inserted between the PTCBi layer and cathode. An ORMOCERR layer was used as encapsulation layer. For excitation an organic light emitting diode is used. The sensor spot and the detector are processed on the same flexible substrate. This approach not only simplifies the detection system by minimizing the numbers of required optical components - no optical filters have to be used for separating the excitation light and the luminescent emission-, but also has a large potential for low-cost sensor applications. The feasibility of the concept is demonstrated by an integrated oxygen sensor, indicating good performance. Sensor schemes for other chemical parameters are proposed.

Kraker, E.; Lamprecht, B.; Haase, A.; Jakopic, G.; Abel, T.; Konrad, C.; Köstler, S.; Tscherner, M.; Stadlober, B.; Mayr, T.

2010-08-01

291

Simultaneous quantification of six main active constituents in Chinese Angelica by high-performance liquid chromatography with photodiode array detector  

PubMed Central

Background: Angelica sinensis is a famous traditional Chinese medicinalherb, which is predominantly used in the treatment of gynecological conditions. It is the first report for the simultaneous determination of six major active components in Chinese Angelica, which is important for quality control. Objective: A validated HPLC-PAD method was first developed to evaluate the quality of crude and processed Radix Angelica through simultaneous determination of six bioactive compounds, namely ferulic acid, senkyunolide I, senkyunolide H, coniferyl ferulate, Z/E-ligustilide and Z/E-butylidenephthalide. Materials and Methods: Samples were separated on a Xtimate™C18 column (250 × 4.6 mm, 5 ?m) and detected by PAD. Mobile phase was composed of (A) aqueous phosphoric acid (0.02%, v/v) and (B) acetonitrile (MeCN) (including 10% tetrahydrofuran, v/v) using a gradient elution. Analytes were performed at 30°C with a flow rate of 1.0 mL/min. Results: All calibration curves showed good linear regression (r2 ? 0.9963) within the tested ranges, and the recovery of the method was in the range of 91.927–105.859%. Conclusion: The results demonstrate that the developed method is accurate and reproducible and could be readily utilized as a suitable quality control method for the quantification of Radix Angelica.

Ying, Li; Si-Wang, Wang; Hong-Hai, Tu; Wei, Cao

2013-01-01

292

Integrated readout electronics for Geiger mode avalanche photodiodes  

Microsoft Academic Search

Geiger mode avalanche photodiodes are devices that count single optical photons. Two disadvantages of these devices, afterpulsing and cross talk in arrays, would be significantly reduced if readout electronics is integrated with the avalanche photodiode. The different methods that exist for biasing the diodes are reviewed with special attention towards their application in integrated circuits. So far, these methods have

W. J. Kindt; K. J. de Langen

1998-01-01

293

A miniature dilution refrigerator for sub-Kelvin detector arrays  

Microsoft Academic Search

We describe a miniature dilution refrigerator (MDR), operated in continuous mode and suitable for many detector applications at temperatures down to 50 mK. It distinguishes itself from other refrigerators in that it is self-contained and benefits from an internal cycle of the 3He gas. As a result, no external gas handling system is required so size, weight and complexity of

Gustav Teleberg; Simon T. Chase; Lucio Piccirillo

2006-01-01

294

High-performance ferroelectric and magnetoresistive materials for next-generation thermal detector arrays  

NASA Astrophysics Data System (ADS)

This paper discusses the potential thermal imaging performance achievable from thermal detector arrays and concludes that the current generation of thin-film ferroelectric and resistance bolometer based detector arrays are limited by the detector materials used. It is proposed that the next generation of large uncooled focal plane arrays will need to look towards higher performance detector materials - particularly if they aim to approach the fundamental performance limits and compete with cooled photon detector arrays. Two examples of bolometer thin-film materials are described that achieve high performance from operating around phase transitions. The material Lead Scandium Tantalate (PST) has a paraelectric-to-ferroelectric phase transition around room temperature and is used with an applied field in the dielectric bolometer mode for thermal imaging. PST films grown by sputtering and liquid-source CVD have shown merit figures for thermal imaging a factor of 2 to 3 times higher than PZT-based pyroelectric thin films. The material Lanthanum Calcium Manganite (LCMO) has a paramagnetic to ferromagnetic phase transition around -20oC. This paper describes recent measurements of TCR and 1/f noise in pulsed laser-deposited LCMO films on Neodymium Gallate substrates. These results show that LCMO not only has high TCR's - up to 30%/K - but also low 1/f excess noise, with bolometer merit figures at least an order of magnitude higher than Vanadium Oxide, making it ideal for the next generation of microbolometer arrays. These high performance properties come at the expense of processing complexities and novel device designs will need to be introduced to realize the potential of these materials in the next generation of thermal detectors.

Todd, Michael A.; Donohue, Paul P.; Watton, Rex; Williams, Dennis J.; Anthony, Carl J.; Blamire, Mark G.

2002-12-01

295

Array-based vapor sensing using conductive carbon black-polymer composite thin film detectors  

NASA Astrophysics Data System (ADS)

A simple, broadly responsive detector array, based on polymer-carbon black composites that can detect, classify, and quantify various vapors and vapor mixtures is described. The individual detector elements of the array are constructed from films consisting of carbon black particles dispersed into insulating organic polymers. The carbon black provides an electrically conductive network in the films, whereas the different organic polymers are the source of chemical diversity between elements in the detector array. Swelling of the polymer upon exposure to a vapor increases the electrical resistance of the film by disrupting the conductive network of carbon black particles, thereby providing a simple means for monitoring the presence of a vapor. The dc electrical resistance change of an individual composite is shown to be consistent with the predictions of percolation theory. The differing gas-solid partition coefficients between vapor analytes for the various polymers of the detector array produce a characteristic pattern of resistance changes for each analyte. The response of these detectors is linear with variations in analyte concentration, allowing quantification as well as identification of a test analyte. This type of detector array can be used to discriminate different classes of analyte molecules (such as aromatics from alcohols) as well as those within a particular class (such as benzene from toluene and methanol from ethanol). Additionally, by using polymers with chiral subunits, enantiomerically different vapors can be discriminated. Principle component data analysis is used to identify and quantify airborne analytes and the relative compositions of simple gas mixtures. Integration of the electrical resistance signals with data analysis software has made sensing and analysis functions possible in a compact, low-power, simple vapor sensor device.

Severin, Erik Jon

296

Measurement of the UHECR Flux by the Telescope Array Fluorescence Detectors  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA), the first dedicated Northern Hemisphere ``hybrid'' ultrahigh energy cosmic ray (UHECR) detector, is online in Millard Country, Utah. The three Fluorescence Detector sites (FD) located at Black Rock Mesa, Long Ridge and Middle Drum have been taking data since November 2007. By measuring the characteristics of UHECR-induced extensive air showers using the FD, we can measure the energies, composition and arrival directions of the highest- energy cosmic rays. We will show data from the experiment, comparisons with simulated data from our full detector Monte Carlo simulation program, and our measurement of the UHECR energy spectrum. )

Stratton, Sean; Scott, Lauren

2010-02-01

297

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

SciTech Connect

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

Olson, D.; Greiman, W.; Hall, D.; Balaban, D.; Day, C. (Lawrence Berkeley Laboratory, Berkeley, CA (USA))

1990-08-01

298

Research on Avalanche Photodiode Based Photon Imaging System  

Microsoft Academic Search

In order to realize ultra low light level detection and fast response on military, the problems existing in present low light level (LLL) imaging systems are analyzed, a novel imaging system based on avalanche photodiode (APD) detector is proposed. This system is composed of optical system, avalanche photodiode, quench circuit, Peltier cooling setup, signal processing circuit, display element and power

Liju Yin; Qian Chen; Songfeng Kou; Jian Qin

2009-01-01

299

NOY: a neutrino observatory network project based on stand alone air shower detector arrays  

NASA Astrophysics Data System (ADS)

We have developed a self powered stand alone particle detector array dedicated to the observation of horizontal tau air showers induced by high energy neutrinos interacting in mountain rock. Air shower particle detection reaches a 100% duty cycle and is practically free of background when compared to Cherenkov light or radio techniques. It is thus better suited for rare neutrino event search. An appropriate mountain to valley topological configuration has been identified and the first array will be deployed on an inclined slope at an elevation of 1500 m facing Southern Alps near the city of Grenoble (France). A full simulation has been performed. A neutrino energy dependent mountain tomography chart is obtained using a neutrino and tau propagation code together with a detailed cartography and elevation map of the region. The array acceptance is then evaluated between 1 PeV and 100 EeV by simulating decaying tau air showers across the valley. The effective detection surface is determined by the shower lateral extension at array location and is hence much larger than the array geometrical area. The array exposure will be 1014 cm2 sr s at 100 PeV. Several independent arrays can be deployed with the aim of constituting a large distributed observatory. Some other sites are already under study. At last, special care is dedicated to the educational and outreach aspects of such a cosmic ray detector.

Montanet, F.; Lebrun, D.; Chauvin, J.; Lagorio, E.; Stassi, P.

2011-09-01

300

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

301

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

NASA Astrophysics Data System (ADS)

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

1997-06-01

302

Search for ultra-high energy photons using Telescope Array surface detector  

Microsoft Academic Search

We search for ultra-high energy photons by analyzing geometrical properties of shower fronts of events registered by the Telescope Array surface detector. By making use of an event-by-event statistical method, we derive an upper limit on the absolute flux of primary photons with energies above 1019 eV.

G. I. Rubtsov; D. Ivanov; B. T. Stokes; G. B. Thomson; S. V. Troitsky

2011-01-01

303

Search for ultra-high energy photons using Telescope Array surface detector  

SciTech Connect

We search for ultra-high energy photons by analyzing geometrical properties of shower fronts of events registered by the Telescope Array surface detector. By making use of an event-by-event statistical method, we derive an upper limit on the absolute flux of primary photons with energies above 10{sup 19} eV.

Rubtsov, G. I.; Troitsky, S. V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, 117312 (Russian Federation); Ivanov, D.; Stokes, B. T. [Rutgers - State University of New Jersey, Piscataway (United States); Thomson, G. B. [University of Utah, High Energy Astrophysics Institute, Salt Lake City, Utah (United States)

2011-09-22

304

Cross-talk-free multiplexed immunoassay using a disposable electrochemiluminescent immunosensor array coupled with a non-array detector.  

PubMed

A disposable electrochemiluminescent (ECL) immunosensor array was fabricated on a screen-printed carbon electrode (SPCE) substrate to perform multiplexed immunoassay (MIA) for the first time. The SPCE substrate was composed of an array of four carbon working electrodes, one common Ag/AgCl reference electrode, and one common carbon counter electrode. The immunosensor array was constructed by site-selectively immobilizing multiple antigens on different working electrodes of the SPCE substrate. With a competitive immunoassay format, the immobilized antigens competed with antigens in the sample to capture their corresponding tri(2,2'-bipyridyl)ruthenium(II)-labeled antibodies. The ECL signals from the immunosensors in this array were sequentially detected by a photomultiplier with the aid of a homemade single-pore-four-throw switch. Due to the ECL readout mechanism and the sequential detection mode, it could avoid the cross-talk between the adjacent immunosensors, which was common in other reported immunosensor array. Human, rabbit and mouse immunoglobulin Gs were near-simultaneously assayed as the model analytes. The linear ranges for them were 10-400, 20-400, and 20-400 ng/mL, with detection limits of 2.9, 6.1 and 6.5 ng/mL (S/N=3), respectively. This novel ECL strategy based on immunosensor array coupled with non-array detector provided a simple, sensitive, low-cost and time-saving approach for MIA. It showed great application potential in point-of-care test and field analysis of bio-agents, with mass production potential and high throughput. PMID:21778047

Li, Cuifang; Fu, Zhifeng; Li, Zongyun; Wang, Zhenxing; Wei, Wei

2011-07-01

305

Calculation of narcissus effect in scanning systems with detector arrays by exact numerical ray tracing  

NASA Astrophysics Data System (ADS)

The narcissus-effect is a well known phenomena in IR-scanning systems. Several methods of calculation have been proposed. Due to advances in IR-detector technology it is now possible to use detector line-arrays instead of single detectors for scanning systems. We have modified the model published by A. S. Lau. In our calculations the transmission of all optical components is taken into account, especially the transmission of the imager is also considered. We have developed a program based on this model. With this tool the calculations of the narcissus-equivalent temperature can be done by exact numerical ray-tracing for an array with up to twelve detectors. Separately for each of them you can see the exact narcissus-effect over the whole scan angle, showing a varying intensity over the detector array. The calculation can be done in arbitrary small steps over the whole scanning angle. Thus it is possible to take into account all effects of vignetting due to the mountings of the components or any other mechanical limitations. An example of such a scanning system is presented.

Kroeninger, Werner

1993-04-01

306

Thermal IR imaging system using a self-scanned HgCdTe/CCD detector array  

NASA Astrophysics Data System (ADS)

It is likely that future high resolution earth observation imaging systems will utilize self-scanned IR detectors. In an initial step toward this goal, an IR imaging system operating in the 10 to 12 micron spectral region has been developed. This system uses a 9-element HgCdTe/CCD linear array operating in the photoconductive mode, nine pre-amplifiers and a silicon CCD multiplexer integrated into a focal plane assembly. Opto-mechanical techniques are used to scan the scene and images are produced in real time. The imaging performance of this system is described and measurements of noise, responsivity, specific detectivity, and detector sensitivity profiles are presented. The requirements for more advanced detector arrays for use in future NASA remote sensing missions are also discussed.

Husain-Abidi, A. S.; Ostrow, H.; Rubin, B.

1980-01-01

307

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

308

Use of backscattered electron detector arrays for forming backscattered electron images in the scanning electron microscope.  

PubMed

The backscattered electron (BSE) signal in the scanning electron microscope (SEM) can be used in two different ways. The first is to give a BSE image from an area that is defined by the scanning of the electron beam (EB) over the surface of the specimen. The second is to use an array of small BSE detectors to give an electron backscattering pattern (EBSP) with crystallographic information from a single point. It is also possible to utilize the EBSP detector and computer-control system to give an image from an area on the specimen--for example, to show the orientations of the grains in a polycrystalline sample ("grain orientation imaging"). Some further possibilities based on some other ways for analyzing the output from an EBSP detector array, are described. PMID:16502623

Wells, O C; Gignac, L M; Murray, C E; Frye, A; Bruley, J

309

Spatial resolution of 2D ionization chamber arrays for IMRT dose verification: single-detector size and sampling step width  

Microsoft Academic Search

The spatial resolution of 2D detector arrays equipped with ionization chambers or diodes, used for the dose verification of IMRT treatment plans, is limited by the size of the single detector and the centre-to-centre distance between the detectors. Optimization criteria with regard to these parameters have been developed by combining concepts of dosimetry and pattern analysis. The 2D-ARRAY Type 10024

Björn Poppe; Armand Djouguela; Arne Blechschmidt; Kay Willborn; Antje Rühmann; Dietrich Harder

2007-01-01

310

High speed, low read noise electronics for astronomy detector arrays  

SciTech Connect

The third generation electronics system of the Berkeley infrared camera has been built with improved frame rate, size, manufacturability, and real-time data processing power. The flexibility to easily operate a variety of detectors and the vast improvement in speed was achieved by using Motorola DSP56001 Digital Signal Processors (DSP) to serve as controllers and processing elements throughout the system. The new data acquisition system has one DSP per analog channel, making the system scalable to match the sensor being used. Each channel can run up to 1 MHz sampling rate (A/D limited) using 20% of the DSP's 10-30 MIPS bandwidth for interrupt driven data acquisition, leaving 80% for background processes. The A/D is presently a 1 MHz 12 bit unit. The conversion resolution is enhanced by a pattern subtraction system allowing the removal of the first order signal and digitization of the amplified residual.

Peck, M.C.; Arens, J.F.; Jernigan, J.G.; Goalema, S.D.

1989-02-01

311

Characterization of flight detector arrays for the wide-field infrared survey explorer  

NASA Astrophysics Data System (ADS)

The Wide-field Infrared Survey Explorer is a NASA Midex mission launching in late 2009 that will survey the entire sky at 3.3, 4.7, 12, and 23 microns (PI: Ned Wright, UCLA). Its primary scientific goals are to find the nearest stars (actually most likely to be brown dwarfs) and the most luminous galaxies in the universe. WISE uses three dichroic beamsplitters to take simultaneous images in all four bands using four 1024×1024 detector arrays. The 3.3 and 4.7 micron channels use HgCdTe arrays, and the 12 and 23 micron bands employ Si:As arrays. In order to make a 1024×1024 Si:As array, a new multiplexer had to be designed and produced. The HgCdTe arrays were developed by Teledyne Imaging Systems, and the Si:As array were made by DRS. All four flight arrays have been delivered to the WISE payload contractor, Space Dynamics Laboratory. We present initial ground-based characterization results for the WISE arrays, including measurements of read noise, dark current, flat field and latent image performance, etc. These characterization data will be useful in producing the final WISE data product, an all-sky image atlas and source catalog.

Mainzer, Amy; Larsen, Mark; Stapelbroek, Maryn G.; Hogue, Henry; Garnett, James; Zandian, Majid; Mattson, Reed; Masterjohn, Stacy; Livingston, John; Lingner, Nicole; Alster, Natali; Ressler, Michael; Masci, Frank

2008-08-01

312

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

313

Detector construction  

Microsoft Academic Search

Methods for constructing radiation sensitive detectors are described. In one method, distinct layers of optical cement and plastics material are disposed between a semiconductor photodiode and a layer of rare earth phosphor in order to permit the phosphor and the plastics material to be peeled from the optical cement without damaging the photodiode in the event of a problem arising

1981-01-01

314

Portable optical water-and-oil analyzer based on a mid-IR (1.6-2.4 ?m) optron consisting of an LED array and a wideband photodiode  

NASA Astrophysics Data System (ADS)

An optical method for measuring the water and oil content using mid-IR (1.6-2.4 ?m) LEDs and a wideband photodiode is suggested for the first time. This method is developed based on the absorption spectra of pure water, dewatered oil, and water—oil emulsions (cut oil) with different content of water and uses 10 types of LEDs in the spectral range 1.6-2.4 ?m. It is shown that pure water heavily absorbs the LED radiation in the spectral range 1.85-2.05 ?m, oil absorbs in the range 1.67-1.87 ?m, and the LED radiation with a maximum at 2.20 ?m is equally weakly absorbed by water and oil. An optical cell of the water-and-oil analyzer is designed on the basis of a three-element diode array with radiation maxima at 1.65 (detection of oil), 1.94 (detection of water), and 2.2 ?m (reference signal) wideband photodiode covering the spectral range 1.3-2.4 ?m. A calibration curve is derived that represents the dependence of the water concentration in oil on the amplitude of the reduced signal obtained by processing three signals from the LEDs. This optical method of measuring the water content in oil underlies a portable analyzer making possible online measurements directly in an oil well.

Kalinina, K. V.; Molchanov, S. S.; Stoyanov, N. D.; Astakhova, A. P.; Salikhov, Kh. M.; Yakovlev, Yu. P.

2010-02-01

315

Avalanche Photodiode Photon Counting Receivers for Space-Borne Lidars.  

National Technical Information Service (NTIS)

Avalanche photodiodes (APD) are studied for uses as photon counting detectors in spaceborne lidars. Non-breakdown APD photon counters, in which the APD's are biased below the breakdown point, are shown to outperform: (1) conventional APD photon counters b...

X. Sun F. M. Davidson

1991-01-01

316

3D Dose Verification Using Tomotherapy CT Detector Array  

SciTech Connect

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

Sheng Ke, E-mail: ks2mc@virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Jones, Ryan; Yang Wensha; Saraiya, Siddharth; Schneider, Bernard [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Chen Quan; Sobering, Geoff; Olivera, Gustavo [TomoTherapy, Inc., Madison, WI (United States); Read, Paul [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

2012-02-01

317

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

318

Speckle-based modulation transfer function measurements for comparative evaluation of CCD and CMOS detector arrays  

NASA Astrophysics Data System (ADS)

Charge-coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) matrices offer excellent features in imaging systems. For assessing the suitability of each technology according to the application, the complete characterization of the detector arrays becomes necessary. A system is optically characterized by the modulation transfer function (MTF). We have comparatively studied the results provided by the speckle method for detectors of two types: CCD and CMOS. To do so, we first analysed the precision in determining the MTF of the CCD using two apertures at the exit port of an integrating sphere: a single and a double-slit. For the single-slit, we propose a new procedure of fitting the experimental data which overcomes the drawbacks of the conventional procedure. Since it offered lower uncertainty and better reproducibility, the single-slit was used for the study with the CMOS detector. Significant differences were found between the MTF of the CCD and the CMOS detectors.

Fernández-Oliveras, Alicia; Pozo, Antonio M.; Rubiño, Manuel

2013-01-01

319

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

NASA Astrophysics Data System (ADS)

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays (UHECRs) with primary energies above 1.6 × 1018 eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 × 1018 eV and a steepening at 5.4 × 1019 eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of UHECR surface detector data, that involves generating a complete simulation of UHECRs striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the "thinning" approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned.

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Machida, S.; Martens, K.; 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.; 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.; Zundel, Z.

2013-05-01

320

Operation of a multiple cell array detector in plasma experiments with a heavy ion beam diagnostic  

SciTech Connect

A multiple cell array detector (MCAD) has been developed to investigate the spatial structure of plasma turbulence in fusion plasmas. This system is expected to provide simultaneous measurements of edge and core density fluctuations with both temporal and spatial resolution, extending the range and number of the sample volumes simultaneously recorded by a heavy ion beam diagnostic (HIBD). Since the detector (usually located close to the vessel wall of a plasma device) operates in a strong plasma radiation environment, the effective shielding of the detector presents a special problem. This article describes and compares the MCAD operation conditions on ISTTOK tokamak and TJ-II stellarator. Experimental results of the detector performance are presented together with the first measurements of n{sub e}{sigma}{sub eff} in the TJ-II plasmas.

Goncalves, B.; Malaquias, A.; Nedzelskiy, I. S.; Pereira, L.; Silva, C.; Varandas, C.A.F.; Cabral, J.A.C.; Khrebtov, S.M.; Dreval, N.B.; Krupnik, L.I.; Hidalgo, C.; Depablos, J. [Associacao EURATOM/IST, Centro de Fusao Nuclear, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal); Institute of Plasma Physics, National Scientific Center, Kharkov Institute of Physics and Technology, 61108 Kharkov (Ukraine); Laboratorio Nacional de Fusion por Confinamento Magnetico, EURATOM/CIEMAT, 28040 Madrid (Spain)

2004-10-01

321

Real-time imaging detectors for portal imaging  

Microsoft Academic Search

This paper reviews the status of real-time imaging systems which are used in radiation-therapy for radiotherapy localization and verification. Imaging systems under review include (1) metal- fluorescent screens, optically coupled to video cameras; (2) metal-phosphor screen in direct contact with two-dimensional photo-diode array (flat panel detector); (3) two-dimensional liquid ionization chamber; and (4) linear diode arrays. These systems permit frequent

Hans Roehrig; Chee-Wai Cheng

1993-01-01

322

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

323

Integrated thermoelectric cooler/package for infrared detector array temperature stabilization  

NASA Astrophysics Data System (ADS)

Thermoelectric Coolers (TEC"s) are reversible heat pumps which can be employed for cooling and/or temperature stabilization of critical electronic circuits which might become in-operable without removal of the heat generated within the device. Thermoelectric temperature stabilization is often used in uncooled Infrared imaging systems due to the temperature sensitive nature of the detector array. These Infrared systems operate in environments where the ambient temperature changes. The TEC is used to either heat or cool the detector array to its optimized temperature. The integrated TEC concept involves soldering of individual thermoelectric elements directly in the base of the package. The package is made from metallized multi-layer ceramic which includes electrical pins for both the TEC and the detector array. Integrating the cooler directly into the package offers many advantages. It reduces the number of piece parts in the system, the number of soldering or bonding operations, allows for a higher temperature assembly, and eliminates the TEC mounting operation for detector manufacturers. The integrated TEC can be designed to meet operative parameters such as power, temperature delta, slew rate, size, and robustness. The purpose of this document is to provide assistance to design engineers on key design parameters and considerations when including an integrated thermoelectric cooler into the assembly.

Zamboni, John M.

2003-12-01

324

Improving the angular resolution for the silicon detectors of the STARS array  

NASA Astrophysics Data System (ADS)

The STARS (Silicon Telescope Array for Reaction Studies) array at LBNL is used to measure the emission angles of light charged particles (protons, deuterons and tritons) following transfer reactions. The array consists of two CD-shaped silicon energy detectors: a thin ``delta E'' detector and a thicker ``E'' detector, each segmented into twenty-four concentric rings. The angle at which a particle hits the delta E detector is typically approximated in the off-line analysis code as the angle from the beam axis to the center of the ring traversed by the particle. To improve angular resolution, a new method of approximating the angle was investigated. It was thought that energy loss in the delta E could be used to derive angle. SRIM was used to create functions of energy loss per unit distance with respect to particle energy. These functions were used in Fortran codes to create matrices of energy loss for a range of angles and final energies. The matrices were then worked into the off-line analysis code. Preliminary results will be shown. This work is partly supported by the DOE under grant numbers DE-FG02-52NA26206 and DE-FG02-05ER41379.

Shaw, John; Pauerstein, Benjamin; Chen, Danyi; Ross, Timothy; Hughes, Richard; Beausang, Con

2010-11-01

325

Novel reentry vehicle instrument: The photodiode  

Microsoft Academic Search

Photodiodes are used as detectors to provide a simple, inexpensive, and reliable method of obtaining data pertaining to reentry vehicle flight performance. These devices are used primarily to measure boundary layer transition onset, but can also measure vehicle roll rate and roll position. This paper will describe the instrument, construction details, installation, cost, and advantages, and will conclude with supporting

S. R. Blodgett; B. T. Conrad; K. W. Shrock; A. C. Wilken; M. W. Sterk; R. J. Chaffin

1986-01-01

326

A novel reentry vehicle instrument - The photodiode  

Microsoft Academic Search

Photodiodes are used as detectors to provide a simple, inexpensive, and reliable method of obtaining data pertaining to reentry vehicle flight performance. These devices are used primarily to measure boundary layer transition onset, but can also measure vehicle roll rate and roll position. This paper will describe the instrument, its construction details, installation, cost, and advantages, and will conclude with

S. R. Blodgett; B. T. Conrad; K. W. Shrock; A. C. Wilken; M. W. Sterk; R. J. Chaffin

1986-01-01

327

Novel reentry vehicle instrument - the photodiode  

SciTech Connect

Photodiodes are used as detectors to provide a simple, inexpensive, and reliable method of obtaining data pertaining to reentry vehicle flight performance. These devices are used primarily to measure boundary layer transition onset, but can also measure vehicle roll rate and roll position. This paper will describe the instrument, construction details, installation, cost, and advantages, and will conclude with supporting flight data.

Blodgett, S.R.; Conrad, B.T.; Shrock, K.W.; Wilken, A.C.; Sterk, M.W.; Chaffin, R.J.

1986-01-01

328

Materials preparation and fabrication of pyroelectric polymer/silicon MOSFET detector arrays. Final report  

SciTech Connect

The authors have delivered several 64-element linear arrays of pyroelectric elements fully integrated on silicon wafers with MOS readout devices. They have delivered detailed drawings of the linear arrays to LANL. They have processed a series of two inch wafers per submitted design. Each two inch wafer contains two 64 element arrays. After spin-coating copolymer onto the arrays, vacuum depositing the top electrodes, and polarizing the copolymer films so as to make them pyroelectrically active, each wafer was split in half. The authors developed a thicker oxide coating separating the extended gate electrode (beneath the polymer detector) from the silicon. This should reduce its parasitic capacitance and hence improve the S/N. They provided LANL three processed 64 element sensor arrays. Each array was affixed to a connector panel and selected solder pads of the common ground, the common source voltage supply connections, the 64 individual drain connections, and the 64 drain connections (for direct pyroelectric sensing response rather than the MOSFET action) were wire bonded to the connector panel solder pads. This entails (64 + 64 + 1 + 1) = 130 possible bond connections per 64 element array. This report now details the processing steps and the progress of the individual wafers as they were carried through from beginning to end.

Bloomfield, P. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Engineering

1992-03-27

329

CCD for SWIR photodiode multiplexing  

NASA Astrophysics Data System (ADS)

A new SWIR focal plane has been designed for the SPOT IV satellite. It consists of a linear array of InGaAs photodiodes, operating at ambient temperature, associated to Si CCD multiplexers. The CCDs are of the two-phase n-buried channel type, operating up to 2 MHz. Their dynamic range exceeds 10,000, with a noise level of 1100 electrons. Any type of current source sensors may be coupled to this readout circuit, which has 150 lateral inputs.

Moy, J. P.; de Cachard, J.; Chaussat, S.

330

APD arrays and large-area APDs via a new planar process  

Microsoft Academic Search

A fabrication process has been developed which allows the beveled-edge-type of avalanche photodiode (APD) to be made without the need for the artful bevel formation steps. This new process, applicable to both APD arrays and to discrete detectors, greatly simplifies manufacture and should lead to significant cost reduction for such photodetectors. This is achieved through a simple innovation that allows

Richard Farrell; Kanai Shah; Kofi Vanderpuye; Ronald Grazioso; Richard Myers; Gerald Entine

2000-01-01

331

Large X-ray detector arrays for physics experiments at a lunar base  

NASA Astrophysics Data System (ADS)

A large array of astronomical X-ray detectors can be constructed at a lunar base, and maintained there for a long time. Such an array permits development of a new astronomical subdiscipline based on collection of very large numbers of X-ray photons from bright X-ray sources. With such data qualitatively new experimental issues can be addressed, in gravitational physics, nuclear physics, and magnetospheric effects. Fundamental questions such as the existence of General Relativistic instabilities in rapidly rotating objects or the probing of orbits near a black hole can be investigated.

Wood, K. S.; Michelson, P. F.

1990-03-01

332

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

333

Development of multi-channel gated integrator and PXI-DAQ system for nuclear detector arrays  

NASA Astrophysics Data System (ADS)

A multi-channel gated integrator and PXI based data acquisition system have been developed for nuclear detector arrays with hundreds of detector units. The multi-channel gated integrator can be controlled by a programmable GI controller. The PXI-DAQ system consists of NI PXI-1033 chassis with several PXI-DAQ cards. The system software has a user-friendly GUI which is written in C language using LabWindows/CVI under Windows XP operating system. The performance of the PXI-DAQ system is very reliable and capable of handling event rate up to 40 kHz.

Kong, Jie; Su, Hong; Chen, Zhi-Qiang; Dong, Cheng-Fu; Qian, Yi; Gao, Shan-Shan; Zhou, Chao-Yang; Lu, Wan; Ye, Rui-Ping; Ma, Jun-Bing

2010-10-01

334

Measurement of the UHECR Flux by the Telescope Array Fluorescence Detectors  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA), the first dedicated Northern Hemisphere "hybrid" ultrahigh energy cosmic ray (UHECR) detector, is online in Millard County, Utah. The three Fluorescence Detector sites (FD) located at Black Rock Mesa, Long Ridge, and Middle Drum have been taking data since November 2007. By measuring the characteristics of UHECR-induced extensive air showers using the FD, we can measure the energies, composition and arrival directions of the highest energy cosmic rays. We will show data from the experiment, comparisons with simulated data from our full Monte Carlo simulation program and our measurement of the UHECR energy spectrum.

Stratton, Sean; Bergman, Douglas

2011-04-01

335

Design and Implementation of Specialized Analysis Package for a Small, Multi-detector Array  

NASA Astrophysics Data System (ADS)

The YSU Miniball is a small, multi-detector array designed for gamma-ray calorimetry in the study of triggered energy release from nuclear isomers. Analysis of multi-detector data sets is a well known challenge for which software packages such as RadWare and TV have been developed. The particular needs for the analysis of YSU's Miniball data sets are not entirely met by existing software packages. The development and implementation of ProSort, a specialized analysis package, will be discussed.

Propri, Ronald J.; Carroll, James J.; Ugorowski, Philip

2004-10-01

336

Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines  

SciTech Connect

We developed a photodiode-based monochromatic X-ray beam-position monitor (X-BPM) with high spatial resolution for the project beamlines of the NSLS-II. A ring array of 32 Si PIN-junction photodiodes were designed for use as a position sensor, and a low-noise HERMES4 ASIC chip was integrated into the electronic readout system. A series of precision measurements to characterize electrically the Si-photodiode sensor and the ASIC chip demonstrated that the inherent noise is sufficiently below tolerance levels. Following up modeling of detector's performance, including geometrical optimization using a Gaussian beam, we fabricated and assembled a first prototype. In this paper, we describe the development of this new state-of-the-art X-ray BPM along the beamline, in particular, downstream from the monochromator.

Yoon, P.S.; Siddons, D. P.

2009-05-25

337

Acceptance and Angular Resolution of an Infill Array for the Pierre Auger Surface Detector  

SciTech Connect

The Pierre Auger Observatory has been designed to study the highest-energy cosmic rays in nature (E {>=} 1019 eV). The determination of their arrival direction, energy and composition is performed by the analysis of the atmospheric showers they produce. The Auger Surface Array will consist of 1600 water Cerenkov detectors placed in an equilateral triangular grid of 1.5 km. In this paper we show how adding a ''small'' area of surface detectors at half the above mentioned spacing would make it possible to lower the detection threshold by one order of magnitude, thus allowing the Observatory to reach lower energies where the cross-over from galactic to extragalactic sources is expected. We also analyze the angular resolution that can be attained with such an infill array.

Medina, C. [Tandar Laboratory (CAC - CNEA), Buenos Aires (Argentina); Gomez Berisso, M.; Allekotte, I. [I. Balseiro and Centro Atomico Bariloche (CNEA), Bariloche (Argentina); Etchegoyen, A.; Supanitsky, D. [Tandar Laboratory (CAC - CNEA), Buenos Aires (Argentina); CONICET, Buenos Aires (Argentina); Medina-Tanco, G. [I. Astronomico e Geofisico, Univ. de Sao Paulo, Sao Paulo (Brazil)

2007-02-12

338

Measurements of Z(sub eff) profile with a visible bremsstrahlung continuum detector array  

Microsoft Academic Search

A visible bremsstrahlung continuum detector array system was installed in the PBX and JIPP T-IIU tokamaks to provide 16- or 8-channel midplane tangential views of the plasmas. The wavelength measured through an interference filter is near 5230 A in both tokamaks with a passband of 6 A (PBX) and 20 A (JIPP T-IIU). The value of the effective plasma charge

Katsumi Ida

1988-01-01

339

A CFAR detector for MIMO array radar based on adaptive pulse compression-Capon filter  

Microsoft Academic Search

Under the condition of strong clutter and finite training samples, a novel CFAR detector based on the proposed adaptive pulse\\u000a compression-Capon filter (APC-Capon filter) is presented for MIMO array radar which transmits intrapulse coded waveforms.\\u000a Both theoretical analysis and numerical simulations show that the proposed APC-Capon filter can utilize the non-reiterative\\u000a adaptive pulse compression technique to alleviate both range sidelobes

Jian Guan; Yong Huang; You He

340

Optimization of Compton-suppression and summing schemes for the TIGRESS HPGe detector array  

Microsoft Academic Search

Methods of optimizing the performance of an array of Compton-suppressed, segmented HPGe clover detectors have been developed which rely on the physical position sensitivity of both the HPGe crystals and the Compton-suppression shields. These relatively simple analysis procedures promise to improve the precision of experiments with the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS). Suppression schemes will improve the efficiency and peak-to-total

M. A. Schumaker; C. E. Svensson; C. Andreoiu; A. Andreyev; R. A. E. Austin; G. C. Ball; D. Bandyopadhyay; A. J. Boston; R. S. Chakrawarthy; R. Churchman; T. E. Drake; P. Finlay; P. E. Garrett; G. F. Grinyer; G. Hackman; B. Hyland; B. Jones; R. Maharaj; A. C. Morton; C. J. Pearson; A. A. Phillips; F. Sarazin; H. C. Scraggs; M. B. Smith; J. J. Valiente-Dobón; J. C. Waddington; L. M. Watters

2007-01-01

341

PIN detector arrays and integrated readout circuitry on high-resistivity float-zone silicon  

Microsoft Academic Search

A new silicon pin-diode-based pixel detector for ionizing particles integrating a two-dimensional array of detecting elements with readout circuitry has been developed and extensively tested. The signal charge is collected on a low-capacitance electrode avoiding loss of charge into the local readout circuitry within each pixel. The spatial resolution for a given circuitry size is optimized. The approach required back

Walter Snoeys; James D. Plummer; Sherwood Parker; Christopher Kenney

1994-01-01

342

MOCVD growth of ZnO nanowire arrays for advanced UV detectors  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a biocompatible and versatile functional material having a bandgap of 3.37 eV that exhibits both semiconducting and piezoelectric properties and has a diverse group of growth morphologies. We have grown highly ordered vertical arrays of ZnO nanowires (NWs) using a metal organic chemical vapor deposition (MOCVD) growth process on various substrates. The NWs were grown on p-Si (100), SiO2, and m-plane sapphire substrates. The structural and optical properties of the grown vertically aligned ZnO NW arrays were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) measurements. The unique diffraction pattern for ZnO (002) concurred with the SEM inspection indicating vertical orientation of the NWs. UV detectors based on ZnO NWs offer high UV sensitivity and low visible sensitivity for applications such as missile plume detection and threat warning. Compared to the photomultiplier tubes (PMTs) prevalent in current missile warning systems, the NW detector arrays are expected to exhibit low noise, extended lifetimes, and low power requirements for UV detector applications.

Rivera, Abdiel; Mazady, Anas; Zeller, John; Anwar, Mehdi; Manzur, Tariq; Sood, Ashok

2013-03-01

343

Instrumentation development for an array of water Cherenkov detectors for extensive air shower experiments  

NASA Astrophysics Data System (ADS)

A new small array of Cherenkov detectors has been deployed in Tehran, 1200 m above sea level. This array contains four tanks of distilled water with a diameter of 64 cm and a height of 130 cm. The effective area of each tank is about 1382 cm2. They are used to detect air showers and to record the arrival time of the secondary particles. We have collected about 640 000 extensive air showers (EAS) in 8298 h of observation time from November 2006 to October 2007. The distribution of air showers in zenith and azimuth angles has been studied and a cosn? distribution with n = 6.02 ± 0.01 was obtained for the zenith angle distribution. An asymmetry has been observed in the azimuthal distribution of EAS of cosmic rays due to geomagnetic field. The first and second amplitudes of the asymmetry are AI = 0.183 ± 0.001 and AII = 0.038 ± 0.001. Since the recent results are in good agreement with our previous results of scintillation detectors, and tanks of distilled water are cheaper, we prefer to use them instead of scintillators in a future larger array. By simulation, we have improved the size of the detectors to yield the highest efficiency. The best dimensions for each tank with a photomultiplier tube in the center of its lid are 40 cm in diameter and 60 cm in height.

Sheidaei, F.; Bahmanabadi, M.; Keivani, A.; Samimi, J.

2009-11-01

344

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

NASA Astrophysics Data System (ADS)

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

Astheimer, Robert W.

1989-06-01

345

Lung counting: Comparison of a four detector array that has either metal or carbon fiber end caps, and the effect on array performance characteristics  

NASA Astrophysics Data System (ADS)

This study described the performance of an array of HPGe detectors, made by ORTEC. In the existing system, a metal end cap was used in the detector construction. In general, the natural metal contains some radioactive materials, create high background noises and signals during in vivo counting. ORTEC proposed a novel carbon fiber to be used in end cap, without any radio active content. This paper described the methodology of developing a model of the given HPGe array-detectors, comparing the detection efficiency and cross talk among the detectors using two end cap materials: either metal or carbon fiber and to provide a recommendation about the end cap material. The detector's counting efficiency were studied using point and plane sources. The cross talk among the array detectors were studied using a homogeneous attenuating medium made of tissue equivalent material. The cross talk was significant when single or multiple point sources (simulated to heterogeneous hot spots) were embedded inside the attenuating medium. With carbon fiber, the cross talk increased about 100% for photon energy at about 100 keV. For a uniform distribution of radioactive material, the cross talk increased about 5-10% when the end cap was made of carbon instead of steel. Metal end cap was recommended for the array of HPGe detectors.

Sabbir Ahmed, Asm; H. Kramer, Gary

2011-12-01

346

Development of a large scale stressed Ge:Ga detector array for SAFARI  

NASA Astrophysics Data System (ADS)

We report on the development of a large-format stressed gallium doped germanium (Ge:Ge) array for the SAFARI instrument planned for the Japanese infrared satellite SPICA. Building on flight proven PACS heritage, the goal of our development is a 32 pixel stressed Ge:Ga module for the wavelength range between 110 and 210 ?m, being the building block of a 32 × 32 pixel detector array. The unprecedented size of this array would allow the use of almost all of the 3.8 × 3.8 arcmin field of view available to SAFARI in the SPICA focal plane. Our 32 pixel prototype module features three selectable read-out architectures enabling the evaluation and optimization of the detector performance as well as a two stage multiplexer to distribute the dissipative heat load on the temperature stages provided by the satellite. Thermal modeling has shown that the heat loads are in compliance with the thermal budgets of the SPICA cryogenic system. The ultimate development goal with optimized read-out circuits is an NEP of 1 × 10-18 W/Hz1/2, which presents a factor of 8 improvement in noise performance compared to the PACS stressed Ge:Ga array.

Raab, Walfried; Poglitsch, Albrecht; Höhnle, Rainer; Barl, Lothar

2010-07-01

347

Uncooled focal plane array detector development at InfraredVision Technology Corporation  

NASA Astrophysics Data System (ADS)

InfraredVision Technology Corporation ("ITC") has improved the performance of the 320x240 microbolometer Uncooled Focal Plane Array ("UFPA") by increasing the pixel fill-factor. This allows state-of-the-art performance for applications requiring high sensitivity. Measurements taken on microbolometer test structures and detector arrays show a factor of two improvements in the responsivity over that previously reported for our standard 37.5-um pixel UFPA. Performance results for microbolometer pixels ranging in size from 50um down to 15um are presented. Our ITC-1000 series detector product addresses both imaging and radiometric commercial-camera applications. With the development of a high fill-factor pixel design, ITC will soon provide a high-performance VOx microbolometer-based sensor to camera manufacturers requiring state-of-the-art detector performance. FPA performance is presented to demonstrate the sensor improvements accomplished. The use of our on-chip NonUniformity Correction (NUC) feature, available on the ITC-1000 detector, is characterized to demonstrate the performance limitations.

Hay, Kenneth A.; Van Deusen, Dale

2005-05-01

348

Automatic and robust calibration of optical detector arrays for biomedical diffuse optical spectroscopy  

PubMed Central

The design and testing of a new, fully automated, calibration approach is described. The process was used to calibrate an image-guided diffuse optical spectroscopy system with 16 photomultiplier tubes (PMTs), but can be extended to any large array of optical detectors and associated imaging geometry. The design goals were accomplished by developing a routine for robust automated calibration of the multi-detector array within 45 minutes. Our process was able to characterize individual detectors to a median norm of the residuals of 0.03 V for amplitude and 4.4 degrees in phase and achieved less than 5% variation between all the detectors at the 95% confidence interval for equivalent measurements. Repeatability of the calibrated data from the imaging system was found to be within 0.05 V for amplitude and 0.2 degrees for phase, and was used to evaluate tissue-simulating phantoms in two separate imaging geometries. Spectroscopic imaging of total hemoglobin concentration was recovered to within 5% of the true value in both cases. Future work will focus on streamlining the technology for use in a clinical setting with expectations of achieving accurate quantification of suspicious lesions in the breast.

Mastanduno, Michael A.; Jiang, Shudong; DiFlorio-Alexander, Roberta; Pogue, Brian W.; Paulsen, Keith D.

2012-01-01

349

X-ray analog pixel array detector for single synchrotron bunch time-resolved imaging  

PubMed Central

Dynamic X-ray studies can reach temporal resolutions limited by only the X-ray pulse duration if the detector is fast enough to segregate synchrotron pulses. An analog integrating pixel array detector with in-pixel storage and temporal resolution of around 150?ns, sufficient to isolate pulses, is presented. Analog integration minimizes count-rate limitations and in-pixel storage captures successive pulses. Fundamental tests of noise and linearity as well as high-speed laser measurements are shown. The detector resolved individual bunch trains at the Cornell High Energy Synchrotron Source at levels of up to 3.7 × 103?X-rays per pixel per train. When applied to turn-by-turn X-ray beam characterization, single-shot intensity measurements were made with a repeatability of 0.4% and horizontal oscillations of the positron cloud were detected.

Koerner, Lucas J.; Gruner, Sol M.

2011-01-01

350

Pulse-height defect in the passivated ion-implanted Si detectors of the INDRA array  

NASA Astrophysics Data System (ADS)

The pulse-height defect (PHD) of 36Ar, 58Ni, 129Xe, 181Ta and 197Au ions in the 180 passivated ion-implanted silicon detectors of the INDRA array has been measured. The detectors faced the target with the low electric field side. The charge encoding ensured a low ballistic deficit. Detectors with the same nominal characteristics and electric field strength show a PHD dependence on the individual silicon wafer. They are classified and calibrated by using an empirical parametrization which relates the PHD to the total energy through a /Z-depending power law. A PHD analytical formula, based on a simple recombination model, is also proposed. It considers a realistic charge density variation with the position coordinate on the ion path. This new formula is successfully confronted to some experimental data.

T?b?caru, G.; Borderie, B.; Ouatizerga, A.; Pârlog, M.; Rivet, M. F.; Auger, G.; Bacri, C. O.; Bocage, F.; Bougault, R.; Brou, R.; Buchet, P.; Charvet, J. L.; Chbihi, A.; Colin, J.; Cussol, D.; Dayras, R.; Demeyer, A.; Doré, D.; Durand, D.; Ecomard, P.; Frankland, J. D.; Galichet, E.; Genouin-Duhamel, E.; Gerlic, E.; Guinet, D.; Lautesse, P.; Laville, J. L.; Fèvre, A. L.; Lefort, T.; Legrain, R.; Neindre, N. L.; Lopez, O.; Louvel, M.; Nalpas, L.; Nguyen, A. D.; Plagnol, E.; Rosato, E.; Saint-Laurent, F.; Salou, S.; Squalli, M.; Steckmeyer, J. C.; Stern, M.; Tassan-Got, L.; Tirel, O.; Vient, E.; Volant, C.; Wieleczko, J. P.

1999-06-01

351

Test Results of Density Detectors of the Cosmic Ray Air Shower Array in Turku (Finland) (bstract Only).  

National Technical Information Service (NTIS)

The air shower array in Turku is designed to detect multiple hadrons in the cores of small air showers. Test results of the density detector performance and their calibration procedure are presented. The pulse charge distributions of individual photomulti...

A. Elo H. Arvela J. Peltonen J. J. Torsti E. Valtonen

1991-01-01

352

Pixel Array Detector for Time-Resolved X-ray Science, September 1, 1997 - September 14, 2000  

SciTech Connect

Progress on the design, fabrication, testing and assembly of two-layer Pixel Array Detectors (PADs) is described. The PADs are developed for challenging time-resolved X-ray imaging applications at synchrotron radiation X-ray sources.

Gruner, Sol M.

2000-11-07

353

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

354

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

355

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

PubMed Central

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

2012-01-01

356

Silicon PIN diode array hybrids as building blocks for a vertex detector at an asymmetric B-factory.  

National Technical Information Service (NTIS)

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, o...

S. L. Shapiro

1990-01-01

357

MEDEA: a multi element detector array for gamma ray and light charged particle detection at the LNS-Catania  

Microsoft Academic Search

A 4 pi highly granular Mutli Element DEtector Array (MEDEA) for gamma-rays and light charged particles is described. Its basic configuration consists of 180 barium fluoride scintillator crystals, arranged in the shape of a ball, plus a forward angle wall of 120 phoswich detectors. The inner radius of the ball (22 cm) and the distance of the wall from the

E. Migneco; C. Agodi; R. Alba; G. Bellia; R. Coniglione; A. del Zoppo; P. Finocchiaro; C. Maiolino; P. Piattelli; G. Raia; P. Sapienza

1992-01-01

358

Measurement of the Flux of Ultrahigh Energy Cosmic Rays by the Surface Detector of the Telescope Array Experiment  

Microsoft Academic Search

We have measured the flux of ultrahigh energy cosmic rays using the surface detector of the Telescope Array experiment. We developed an analysis technique based solely on the data, using parameterizations similar to those used in the AGASA experiment. We calculated the aperture of the detector by making a detailed Monte Carlo simulation of the experiment, and tested it by

Gordon Thomson; Dmitri Ivanov; Benjamin Stokes

2010-01-01

359

DETECTORS AND EXPERIMENTAL METHODS: Study of the characteristics of a scintillation array and single pixels for nuclear medicine imaging applications  

Microsoft Academic Search

By using a pixelized Nal(Tl) crystal array coupled to a R2486 PSPMT, the characteristics of the array and of a single pixel, such as the light output, energy resolution, peak-to-valley ratio (P\\/V) and imaging performance of the detector were studied. The pixel size of the NaI(TI) scintillation pixel array is 2 mm×2 mm×5 mm. There are in total 484 pixels

Jie Zhu; Hong-Guang Ma; Wen-Yan Ma; Hui Zeng; Zhao-Min Wang; Zi-Zong Xu

2009-01-01

360

Gamma-ray multiplicity measurement of the spontaneous fission of 252Cf in a segmented HPGe\\/BGO detector array  

Microsoft Academic Search

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

D. L. Bleuel; L. A. Bernstein; J. T. Burke; J. Gibelin; M. D. Heffner; J. Mintz; E. B. Norman; L. Phair; N. D. Scielzo; S. A. Sheets; N. J. Snyderman; M. A. Stoyer; M. Wiedeking

2010-01-01

361

Pixel array detector for time-resolved x-ray scattering  

SciTech Connect

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 1024{times}1O24 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 the microsecond range. The device will consist of a fully depleted diode array bump bonded to a CMOS electronic storage capacitor array with eight frames per pixel. The two devices may be separated by a x-ray blocking layer that protects the radiation-sensitive electronics layer from damage. The signal is integrated in the electronics layer and stored in one of eight CMOS capacitors. After eight frames are taken, the data are then read out, using clocking electronics external to the detector, and stored in a RAM disk. Results will be presented on the development of a prototype 4{times}4 pixel electronics layer that is capable of storing at least 10,000 12-keV x-ray photons for a capacity of over 50 million electrons with a noise corresponding to 2 x-ray photons per pixel. The diode detective layer, electronics storage layer along with the radiation damage and blocking layers will be discussed.

Rodricks, B.G. [Argonne National Lab., IL (United States); Barna, S.L.; Gruner, S.M.; Shepherd, J.A.; Tate, M.W.; Wixted, R.L. [Princeton Univ., NJ (United States). Dept. of Physics

1996-01-01

362

A PCI Based Data Acquisition System for Ground Array Detectors with Wireless Synchronization through GPS  

NASA Astrophysics Data System (ADS)

The synchronization of ground based cosmic ray detectors is a recurring problem. Traditional acquisition systems usually drive signal cables from each station of an array of detectors to a central acquisition system. In the context of ULTRA, a support experiment for the EUSO mission, a distributed wireless acquisition system based on a PCI board with synchronization through GPS was developed. The System is composed by several units, one per station and timetags each event on each station. The time differences between the several stations are computed offline. Each unit includes a low-cost, commercial GPS receiver (GPSboard), a custom PCI board (LIP-PAD) and a Personal Computer. The PCI board performs the fine time-tagging and also acquires the PMT signals of the ground array detector. PMT signals are shaped, amplified and then digitized by a 10 bits flash ADC with a frequency of 100 MHz. A digital trigger unit allows to implement several online trigger conditions. On trigger, event data is stored on an onboard memory. The board control and data readout is performed using the PCI bus. The overall time accuracy has been estimated to be better than 5ns.

Assis, P.; Brogueira, P.; Melo, L.; Pimenta, M.; Silva, J. C.; Varela, J.

2003-07-01

363

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

364

Organic photodiodes on newspaper  

NASA Astrophysics Data System (ADS)

We report on the fabrication and characterization of organic photodiodes deposited on ordinary newspaper sheets. Parylene acts as water and chemical barrier layer, an ORMOCER layer serves as an excellent smoothing and base layer for the diodes, which correspond to classical Tang-type bilayer cells. The photodiodes show excellent diode behaviour in current-voltage measurements of the devices under dark and illumination conditions. The spectral response covers the UV and visible spectral range.

Lamprecht, B.; Thünauer, R.; Ostermann, M.; Jakopic, G.; Leising, G.

2005-04-01

365

A compact 64-pixel CsI(T1)/Si PIN photodiode imaging module with IC readout  

SciTech Connect

We characterize the performance of a complete 64-pixel compact gamma camera imaging module consisting of optically isolated 3 mm 3 mm 5 mm CsI(Tl) crystals coupled to a custom array of low-noise Si PIN photodiodes read out by a custom IC. At 50 V bias the custom 64-pixel photodiode arrays demonstrate an average leakage current of 28 pA per 3 mm 3 mm pixel, a 98.5 percent yield of pixels with <100 pA leakage, and a quantum efficiency of about 80 percent for 540 nm CsI(Tl) scintillation photons. The custom 64-channel readout IC uses low-noise preamplifiers, shaper amplifiers, and a winner-take-all (WTA) multiplexer. The IC demonstrates maximum gain of 120 mV / 1000 e-, the ability to select the largest input signal in less than 150 ns, and low electronic noise at 8 ms peaking time ranging from 25 e- rms (unloaded) to an estimated 180 e- rms (photodiode load of 3 pF, 50 pA). At room temperature a complete 64-pixel detector module employing a custom photodiode array and readout IC demonstrates an average energy resolution of 23.4 percent fwhm and an intrinsic spatial resolution of 3.3 mm fwhm for the 140 keV emissions of 99mTc. Construction of an array of such imaging modules is straightforward, hence this technology shows strong potential for numerous compact gamma camera applications, including scintimammography.

Gruber, Gregory J.; Choong, Woon-Seng; Moses, William W.; Derenzo, Stephen E.; Holland, Stephen E.; Pedrali-Noy, Marzio; Krieger, Brad; Mandelli, Emanuele; Meddeler, Gerrit; Wang, Nadine W.

2001-08-09

366

Development of high-speed, low-noise NIR HgCdTe avalanche photodiode arrays for adaptive optics and interferometry  

Microsoft Academic Search

The most promising way to overcome the CMOS noise barrier of infrared AO sensors is the amplification of the photoelectron signal directly at the point of absorption inside the infrared pixel by means of the avalanche gain. HgCdTe eAPD arrays with cut off wavelengths of lambdac ~2.64 mum produced by SELEX-Galileo have been evaluated at ESO. The arrays were hybridized

Gert Finger; Ian Baker; Reinhold Dorn; Siegfried Eschbaumer; Derek Ives; Leander Mehrgan; Manfred Meyer; Jörg Stegmeier

2010-01-01

367

Analysis of crosstalk in front-illuminated InGaAs PIN hetero-junction photovoltaic infrared detector arrays  

NASA Astrophysics Data System (ADS)

Here presented an experimental study on crosstalk in front illuminated planar and mesa-type InP/ InGaAs/ InP PIN hetero-junction photovoltaic infrared detector arrays. A scanning laser beam with an optical wavelength of 1310 nm coupled in a single-mode optical fiber placed within a few microns of the detector array surface was used to measure the crosstalk between the detector pixels. The crosstalk in the detector array varying with the distance between the incident laser spot and the measured pixel was shown. It is suggested that for the deep mesa-type arrays the dominating source of crosstalk is the light reflected from the detector substrate. And the dominating source of crosstalk that occurs in the planar type and shallow mesa type photovoltaic arrays is associated with photo-induced carries generated in the InGaAs absorption layer that diffuse laterally between neighbor pixels. These results gave out the possibility to optimize the detectors structures in order to reduce crosstalk.

Li, Yongfu; Tang, Hengjing; Zhang, Kefeng; Li, Tao; Ning, Jinhua; Li, Xue; Gong, Haimei

2009-07-01

368

Spatially distributed scintillator arrays for diagnosing runaway electron transport and energy behavior in tokamaks  

Microsoft Academic Search

We present details of a new bismuth germanate [Bi4Ge3O12 (BGO)] scintillator array used to diagnose the transport and energy behavior of runaway electrons (REs) in DIII-D. BGO exhibits important properties for these compact detectors including high light yield which sufficiently excites photodiode detectors (8500 photons\\/MeV), high density and atomic numbers of constituent materials which maximizes sensitivity, and relative neutron blindness

A. N. James; E. M. Hollmann; G. R. Tynan

2010-01-01

369

Array-based carbon black-polymer composite vapor detectors for detection of DNT in environments containing complex analyte mixtures  

NASA Astrophysics Data System (ADS)

Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with sorption of vapors producing swelling-induced resistance changes of the detector films. To identify and classify vapors, arrays of such vapor sensing elements have been constructed in which each element of the array contains a different polymer as the insulating phase and a common conductor, carbon black, as the conducting phase. The differing gas-solid partition coefficients for the various polymers of the detector array produce a pattern of differential resistance changes that is used to classify vapors and vapor mixtures. The performance of this detector array system towards 2,4-dinitrotoluene, the predominant signature in the vapor phase above land mines, in the presence high concentrations of water or of acetone has been evaluated.

Briglin, Shawn M.; Freund, Michael S.; Sisk, Brian C.; Lewis, Nathan S.

2001-10-01

370

Faraday cup detector array with electronic multiplexing for multichannel mass spectrometry  

NASA Astrophysics Data System (ADS)

A Faraday cup detector array (FCDA) and electronic multiplexing circuit have been developed for position sensitive ion beam detection. The entire FCDA always remains open to intercept the incident ion beam flux, and each cup is periodically and sequentially discharged through the electronic multiplexer. This produces true multichannel ion beam detection since none of the incident ion beam flux is lost, as is the case for scanning position sensitive detectors, and higher sensitivity detection is thus obtained. The FCDA consists of a one-dimensional or two-dimensional array of individual cups which are electrostatically isolated from each other by means of an intervening ground conductor, with resulting fill factors F of 58% to 85%. Each cup acts as a charge collector and integrator which is quickly discharged during the readout to create a time-multiplexed output signal that gives the position distribution of the ion beam. When N cups are sequentially scanned and read out, the ion collection efficiency is F(1-r/N), where r is the fraction of a clock cycle that is used for resetting the integrating capacitor. With a typical r=0.2, a 64 element array thus provides an ion collection efficiency of better than 0.997F. The device measures absolute ion currents, and has a wide dynamic range from less than 1 pA to more than 100 nA with less than 70 dB of cross talk between cups. The integration of the electronic multiplexer with the FCDA allows the combined unit to operate within a vacuum chamber by means of only a six-pin feedthrough. The FDCA and electronic multiplexer have been used as a position sensitive ion detector in a compact mass spectrometer to produce better than 1 amu resolution over a 200 amu span with a sensitivity of less than 0.8 pA at a 10:1 signal-to-noise ratio.

Scheidemann, A. A.; Darling, R. B.; Schumacher, F. J.; Isakharov, A.

2002-05-01

371

Progress in use of carbon-black-polymer composite vapor detector arrays for land mine detection  

NASA Astrophysics Data System (ADS)

Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with swelling- induced resistance changes of the films signaling the presence of vapors. To identify and classify vapors, arrays of such vapor sensing elements have been constructed. Each element contained a different organic polymer as the insulating phase. The differing gas-solid partition coefficients for the various polymers of the detector array produced a pattern of resistance changes that was used to classify vapors and vapor mixtures. The performance of this system towards DNT, the predominant signature in the vapor phase above land miens, has been evaluated in detail, with robust detection demonstrated in the laboratory in less than 5 s in air at DNT levels in the low ppb range.

Briglin, Shawn M.; Burl, Michael C.; Freund, Michael S.; Lewis, Nathan S.; Matzger, Adam J.; Ortiz, D. Nelson; Tokumaru, Phil

2000-08-01

372

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

373

Characterization of thermal cross-talk in a MEMS-based thermopile detector array  

NASA Astrophysics Data System (ADS)

The spectral resolution of a MEMS-based IR microspectrometer critically depends on the thermal cross-talk between adjacent TE elements in the detector array. Thermal isolation between elements is realized by using bulk micromachining directly following CMOS processing. This paper reports on the characterization results of bridge-shaped TE detector elements that are cut out of a membrane. Elements with dimensions of 650 × 36 µm2 are separated by 10 µm wide gaps in order to minimize the thermal cross-talk by heat conduction through the support structure. The static and dynamic aspects of thermal cross-talk have been evaluated with an emphasis on the effect of the thermal conductivity of air as a function of the package pressure.

Wu, H.; Grabarnik, S.; Emadi, A.; de Graaf, G.; Wolffenbuttel, R. F.

2009-07-01

374

Photoresponse of a miniaturized ultrabroad-band low-noise metal-film bolometer detector array  

NASA Astrophysics Data System (ADS)

A miniaturized low-noise metal-film bolometer detector array capable of recording radiation spanning a wide spectral range is presented. The bolometers consist of structured gold layers coated with a black nickel layer to reduce the reflectivity in the long-wavelength range. Investigation of the device`s photoresponse showed sufficient sensitivity at wavelengths lambda =4 mm to 6 AA. The detector unit meets high-vacuum requirements, is bakeable up to 300 degrees C, can withstand high nuclear radiation doses, is insensitive to thermal and electromagnetic interferences and can be operated in high magnetic fields. The cooling time of the bolometer is determined by its thermal properties, being about 70 ms in air. The device has meanwhile been successfully used in a few fusion plasma experiments.

Lang, P. T.; Mast, K. F.

1996-01-01

375

Uncooled focal plane array detector development at InfraredVision Technology Corp.  

NASA Astrophysics Data System (ADS)

InfraredVision Technology Corporation ("ITC") has developed a low-cost Uncooled Focal Plane Array ("UFPA") for commercial applications. The ITC-1000 series detector module has been targeted for both imaging and radiometric camera applications. The 320x240 VOx microbolometer-based sensor exploits a 37.5-?m pixel structure to provide potential cost reduction for the camera manufacturers. The CMOS Readout Integrated Circuit ("ROIC") design offers on-chip nonuniformity correction capability and gain control. As an additional feature, the design allows non-temperature stabilized operation. The integration time can be varied for applications where large variations in infrared radiation must be accommodated. Vacuum packaging of the sensors is accomplished using low-cost metal design. A radiometric version of this detector, the ITC-1100, has also been developed for thermographic applications.

Hay, Kenneth A.; Van Deusen, Dale; Liu, Tina Y.; Kleinhans, William A.

2003-09-01

376

A five-channel, diamond photoconducting x-ray detector array for z- pinch experiments  

SciTech Connect

We have built a five-channel, x-ray detector array based on diamond photoconducting detectors (PCDs). The diamond elements have dimensions of 3 mm {times} 1 mm {times} 1 mm (or 0.5 mm). We use PCDs for their stability, flat spectral response, and low leakage currents. The good time response of diamond PCDs is due to the 100-ps electron/hole recombination time. Filters were designed to give information in the 1--10 keV spectral region. Calibration of the diamond PCDs showed sensitivities between 4--7{times}10{sup {minus}4} A/W for a bias of 100 V. We shall present data from z-pinch experiments on Saturn. 10 refs.

Spielman, R.B.

1992-05-01

377

A five-channel, diamond photoconducting x-ray detector array for z-pinch experiments  

SciTech Connect

We have built a five-channel, x-ray detector array based on diamond photoconducting detectors (PCDs). The diamond elements have dimensions of 3 mm {times} 1 mm {times} 1 mm (or 0.5 mm). We use diamond PCDs for their stability, flat spectral response, and low leakage currents. The good time response of diamond PCDs is due to the 100-ps electron/hole recombination time. Filters were designed to give information in the 1--10-keV spectral region. Calibration of the diamond PCDs showed sensitivities between 4 and 7 {times} 10{sup {minus}4} A/W for a bias of 100 V. We shall present data from {ital z}-pinch experiments on Saturn.

Spielman, R.B. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States))

1992-10-01

378

A five-channel, diamond photoconducting x ray detector array for z-pinch experiments  

NASA Astrophysics Data System (ADS)

We have built a five-channel, x-ray detector array based on diamond photoconducting detectors (PCD's). The diamond elements have dimensions of 3 mm x 1 mm x 1 mm (or 0.5 mm). We use PCD's for their stability, flat spectral response, and low leakage currents. The good time response of diamond PCD's is due to the 100-ps electron/hole recombination time. Filters were designed to give information in the 1-10 keV spectral region. Calibration of the diamond PCD's showed sensitivities between 4-7 x 10(exp -4) A/W for a bias of 100 V. We shall present data from z-pinch experiments on Saturn.

Spielman, R. B.

1992-05-01

379

Low-noise thin-film transistor array for digital x-ray imaging detectors  

NASA Astrophysics Data System (ADS)

A new and novel detector structure is now being investigated to minimize the readout noise of large area TFT arrays. A conventional TFT panel consists of orthogonal arrays of gate lines and data lines. The parasitic capacitance from the crossover of these lines results in a sizable data line capacitance. During image readout, the thermal noise of the charge integrator is greatly magnified by the ratio of the data line capacitance to the feedback capacitance of the charge amplifier. The swinging of the gate voltage will also inject charges in and out of the imaging holding pixel capacitors and contribute to the switching noise in the readout image. By redesigning the layout of the TFT arrays and by coupling linear light source to the bottom side of the TFT array in the same direction as the gate lines, the crossover of gate lines and data lines can be avoided and the data line capacitance can be greatly reduced. Instead of addressing each row of transistors by the switching of the gate control voltage, linear light source with collimators are used to optically switch on and off the amorphous silicon transistors. The transistor switching noise from the swinging of the gate voltages is reduced. By minimizing the data line capacitance and avoiding the swinging of the gate control voltage, the basic TFT readout noise is minimized and lower dose x-rays images can be obtained. This design is applicable to both Direct Conversion and Indirect Conversion panels.

Lee, Denny

2011-03-01

380

Development of a Large Scale Stressed Ge:Ga Detector Array for SAFARI  

NASA Astrophysics Data System (ADS)

We report on the development of a large format stressed gallium doped germanium (Ge:Ge) array for the SAFARI instrument. Building on flight proven PACS heritage, the goal of our development is a 32 pixel stressed Ge:Ga module enabling a 32 × 32 pixel photoconductor array for the wavelength range between 110 and 210 ?m. The unprecedented size of this array would allow the use of almost all of the 3.8 × 3.8 arcmin field of view provided for SAFARI in the SPICA focal plane. We are currently in the process of manufacturing the individual components of the 32 pixel demonstration module. This prototype module will feature three selectable read out architectures enabling the evaluation and optimisation of the detector performance as well as a two stage multiplexer to distribute the dissipative heat load on the temperature levels provided by the satellite. Thermal modeling has shown that the heat loads are in compliance with the thermal budgets of the SPICA cryogenic system. The ultimate development goal with optimised read out circuits is an NEP of 1 × 10-18 W/Hz1/2, which would present a factor of 8 improvement in the noise performance compared to the PACS stressed Ge:Ga array.

Raab, W.; Poglitsch, A.; Höhnle, R.; Barl, L.

2009-12-01

381

Infrared pushbroom camera breadboard using off-the-shelf 2D array of detector  

NASA Astrophysics Data System (ADS)

Performances for nowadays optronic systems require focal plane arrays (FPA) with an increasing number of detectors. The `push- broom' technic is well adapted to earth observation in the visible range with the availability of long linear CCD'S offering thousands of pixels. In the infrared, line scan systems are preferred at the present time because technological difficulties have to be overcome in order to get long linear arrays. Among the most important, are: (1) Difficulties to have a large cold focal plane with a temperature uniformity of a few degrees. (2) Difficulties to get good detection material over large surface. Mechanical or optical butting technology can be used there but with dead pixels and/or side effects. (3) Very low cold shield efficiency due to the geometry of the long linear array. (4) Very high development costs. MATRA DEFENSE UAO has made the design of a new infrared FPA concept which has the advantage to overcome all drawbacks listed previously (patented design). The idea consists to transform the pixel arrangement geometry of a 2D array which is available off the shelf into a long linear FPA using a coherent infrared fiber optic reformatter. In order to demonstrate the feasibility of this new FPA concept, a camera breadboard has been built. This task has been supported by the French MOD (STTE). This paper describes this breadboard and gives main technical performances.

Bernier, Joel; Plainchamp, Patrick; Bardon, Dominique

1994-09-01

382

CdZnTe detector array for a scanning-beam digital x-ray system  

NASA Astrophysics Data System (ADS)

The Scanning-Beam Digital X-ray (SBDX) system promises low- dose cardiac fluoroscopy and angiography with excellent image quality. The system demands a detector capable of high count rates and excellent detection efficiency. Cadmium zinc telluride (CdZnTe) is well suited to these requirements. The SBDX detector comprises sixteen 3-mm-thick, 13.5 mm X 13.5 mm tiles arranged in a 4 X 4 array. Each tile has 144 imaging elements. Thus, the entire detector measures 54.0 mm X 54.0 mm and includes 2,304 imaging elements on a 1.125 mm pitch. Because the SBDX system has a geometric magnification of 3.3, the imaging-element size is consistent with a system spatial-resolution of 2.2 lp/mm. The 3-mm thickness is chosen to guarantee a stopping efficiency of more than 90% at 120 kVp. Each detector tile is flip-chip mounted to a custom- designed integrated circuit (IC) using indium bump bonding techniques. Fabricated in a 1.2-micrometer CMOS process, the IC includes high-speed photon-counting circuitry that operates at rates up to 5 X 106 counts/s(DOT)mm2. The circuitry is designed both to maximize the achievable count- rate and to minimize false double counts due to charge sharing between elements. Testing confirms that the detector performs with minimum cross talk between elements at count rates in excess of 2 X 106 counts/s(DOT)mm2. Measurements of the detective quantum efficiency (DQE) are presented. The relationship between material properties and detector performance is also discussed. The circuit design and device fabrication techniques are applicable to a variety of imaging applications.

Heanue, Joseph A.; Pearson, David A.; Melen, Robert E.

1999-05-01

383

Sprite detectors and staring arrays in Hg(1-x)Cd(x)Te  

NASA Astrophysics Data System (ADS)

The evolution of the Sprite detector from its invention in 1974 to the present is reviewed. The use of anamorphic optics to reduce the effects of carrier diffusion, together with changes to the device shape has produced very high spatial resolution. Improved material and two-dimensional structures have further increased the thermal sensitivity. A brief description of the technology for two-dimensional, electronically addressed diode arrays is also given, together with a discussion of the mechanism of p to n type conversion.

Elliott, C. T.

1988-01-01

384

Compact grating spectrometer with an InSb array detector (Poster)  

NASA Astrophysics Data System (ADS)

A compact cooled grating spectrometer was built and has currently been put into use on several telescopes for near-infrared spectrophotometric observations. The spectrometer with the resolving power between 150 and 300 has been installed in an HD-3 dewar, utilizing an InSb array detector with eight elements. The detectivity when attached to a 2-m class telescope is characterized by 3 ? detection limits of about 1×10-20W cm-2 in the K-band and 6×10-20W cm-2 in the L-band by the typical integration time of 300 sec.

Suto, H.; Mizutani, K.; Maihara, T.; Nakajima, T.

385

Simulations and developments of the Low Energy Neutron detector Array LENA  

NASA Astrophysics Data System (ADS)

Prototypes of the Low Energy Neutron detector Array (LENA) have been tested and compared with detailed GEANT simulations. LENA will consist of plastic scintillation bars with the dimensions 1000×45×10 mm3. The tests have been performed with ?-ray sources and neutrons originating from the neutron-induced fission of 235U. The simulations agreed very well with the measured response and were therefore used to simulate the response to mono-energetic neutrons with different detection thresholds. LENA will be used to detect low-energy neutrons from (p,n)-type reactions with low momentum transfer foreseen at the R3B and EXL setups at FAIR, Darmstadt.

Langer, C.; Algora, A.; Couture, A.; Csatlós, M.; Gulyás, J.; Heil, M.; Krasznahorkay, A.; O'Donnell, J. M.; Plag, R.; Reifarth, R.; Stuhl, L.; Sonnabend, K.; Tornyi, T.; Tovesson, F.

2011-12-01

386

Application of multiparameter coincidence spectrometry using a Ge detectors array to neutron activation analysis  

NASA Astrophysics Data System (ADS)

The method of multiparameter coincidence spectrometry based on /?-/? coincidence is widely used for the nuclear structure studies, because of its high sensitivity to /?-rays. In this study, feasibility of the method of multiparameter coincidence spectrometry for analytical chemistry was examined. Two reference igneous rock samples (JP-1, JB-1a) issued by the Geological Survey of Japan were irradiated at a research reactor, and the /?-rays from the radioisotopes produced via neutron capture reactions were measured using an array of 12Ge detectors with BGO Compton suppressors, GEMINI. Simultaneously 24 elements were analyzed without chemical separation. The observed smallest component was Eu contained in JP-1 with abundance of 4ppb.

Hatsukawa, Y.; Oshima, M.; Hayakawa, T.; Toh, Y.; Shinohara, N.

2002-04-01

387

A report on the laboratory performance of the spectroscopic detector arrays for SPIRE/HSO  

NASA Astrophysics Data System (ADS)

We report the performance of the flight bolometer arrays for the Spectral and Photometric Imaging REceiver (SPIRE) instrument to be on board of the Herschel Space Observatory (HSO). We describe the test setup for the flight Bolometric Detector Assembly (BDA) that allows the characterization of its performance, both dark and optical, in one instrument's cool down. We summarize the laboratory procedure to measure the basic bolometer parameters, optical response time, optical efficiency of bolometer and feedhorn, dark and optical noise, and the overall thermal conductance of the BDA unit. Finally, we present the test results obtained from the two flight units, Spectroscopic Long Wavelength (SLW) and Spectroscopic Short Wavelength (SSW).

Nguyen, Hien T.; Bock, James J.; Ringold, Peter; Battle, John; Elliott, Steven C.; Turner, Anthony D.; Weilert, Mark; Hristov, Viktor V.; Schulz, Bernhard; Ganga, Ken; Zhang, L.; Beeman, Jeffrey W.; Ade, Peter A. R.; Hargrave, Peter C.

2004-10-01

388

Controlling dark current in type-II superlattice photodiodes  

Microsoft Academic Search

Limiting the defect-mediated dark currents in type-II superlattice (T2SL) IR photodiodes remains the key challenge to focal plane arrays (FPAs) based on this material system. In spite of its larger effective mass to suppress tunneling and more than an order of magnitude longer Auger lifetime, the T2SL photodiode performance still lags behind that of the incumbent HgCdTe-based technology. The tunneling

C. L. Canedy; E. H. Aifer; J. H. Warner; I. Vurgaftman; E. M. Jackson; J. G. Tischler; S. P. Powell; K. Olver; J. R. Meyer; W. E. Tennant

2009-01-01

389

A Monte-Carlo simulation study of detector array design for dedicated breast metabolic imaging systems  

SciTech Connect

Development of dedicated metabolic breast imaging systems promise to improve the early detection of cancers in women with radio-dense and/or cystic breasts. Our group is constructing an imager based on discrete detector arrays that will acquire multi-angle data to produce tomographic images of the breast. The goal of this investigation was to utilize Monte-Carlo simulations to determine the effect of detector element dimensions on breast lesion detectability. Specifically, the Geant4 Application for Tomography Emission (GATE) software package was used to simulate the performance of the new system. Scanners configured with detector arrays having square elements with widths of 1.5, 2 and 3 mm, and thicknesses of 10, 15 and 20 mm were tested. An ellipsoid filled with 18F containing four spheres with diameters of 5, 4, 3 and 2 mm also filled with 18F (target-to-background ratio=8.5:1) was used to simulate a breast with tracer-avid tumors. Images were created with an iterative maximum likelihood expectation maximization (MLEM) image reconstruction algorithm. Lesion detectability was assessed by calculating the peak signal-to-noise ratio for each sphere. Since the GATE software does not model optical effects in the scintillator, a simulation study investigating photon transport in the detector elements using DETECT97 was performed. Results from these studies indicated that narrow (1.5 or 2.0 mm wide) elements 10 or 15 mm in length should produce an imager that would detect breast lesions 3 mm in diameter.

Raymond R. Raylman; Mark F. Smith; Peter R. Menge

2005-12-01

390

An aging study of the signal and noise characteristics in large-area CMOS detectors  

Microsoft Academic Search

For a detector consisting of a phosphor screen and a photodiode array made by complementary metal-oxidesemiconductor (CMOS) process, we have experimentally re-investigated the long-term stability of the signal and noise characteristics as a function of the accumulated dose at the entrance surface of the detector in addition to the previous study [IEEE Trans. Nucl. Sci. 56(3) 1121 (2009)]. The irradiation

Jong Chul Han; Seungman Yun; Chang Hwy Lim; Tae Gyun Youm; Sung Kyn Heo; Tae Woo Kim; Ian Cunningham; Ho Kyung Kim

2010-01-01

391

Evaluation of a photon-counting detector for Doppler ion temperature measurements (abstract)  

Microsoft Academic Search

A photon-counting detector for determination of the ion temperature in magnetically confined plasmas has been developed.1 The detector is based around an image intensifier tube which is fiber optically coupled to a self-scanning linear photodiode array. The image intensifier incorporates three high strip current (?280 ?A) microchannel plates in a ‘‘Z’’ configuration. Frame times of 10 ?s are possible through

R. D. Benjamin; A. Nudelfuden; J. L. Terry; H. W. Moos

1985-01-01

392

Evaluation of a photon-counting detector for Doppler ion temperature measurements  

Microsoft Academic Search

A photon-counting detector for determination of the ion temperature in magnetically confined plasmas has been developed. The detector is based around an image intensifier tube which is fiber optically coupled to a self-scanning linear photodiode array. The image intensifier incorporates three high strip current (approx. 280 ..mu..A) microchannel plates in a Z configuration. Frame times of 10 ..mu..s are possible

R. D. Benjamin; A. Nudelfunden; J. L. Terry; H. W. Moos

1985-01-01

393

Infrared photodiodes based on Type-II strained layer superlattices  

NASA Astrophysics Data System (ADS)

The InAs/GaSb Type II strained layer superlattice (SLS) is promising III-V material system for infrared (IR) devices due to the ability to engineer its bandgap between 3-30 ?m and potentially have many advantages over current technologies such as high uniformity smaller leakage current due to reduced Auger recombination which are crucial for large IR focal plane arrays. However, an issue with this material system is that it relies on growth on GaSb substrates. These substrates are significantly more expensive than silicon, used for HgCdTe detectors, lower quality and are only available commercially as 3" diameters. Moreover it has to go through thinning down before it could be hybridized to readout integrated circuits. GaAs substrate is a possible alternative. We report on growth and characterisation of Type-II InAs/GaSb SLS photodiodes grown on GaAs substrates for mid-wave infrared with peak responses of 3.5 ?m at 77K and 4.1 ?m at 295K. Comparisons with similar structure grown on GaSb substrates show similar structural, optical and electrical characteristics. Broadening of X-ray rocking curves were observed on the structure grown on GaAs substrate. A full width half maximum (FWMH) of 25.2 arc sec. for the superlattice was observed near ~30.4 degree for the structure on GaSb substrate compared to near ~30.4 degree for structure grown on GaAs. However peak responsivity values of ~ 1.9 A/W and ~ 0.7 A/W were measured at 77K and 295K for devices grown on GaAs substrate. Room temperature responsivity suggests that these photodiodes are promising as high temperature IR detectors.

Das, Sankha D.; Goh, Yu Ling; Tan, Chee Hing; David, John Paul R.; Rodriguez, Jean-Baptiste; Plis, Elena A.; Sharma, Yagya D.; Kim, Ha Sul; Krishna, Sanjay

2008-10-01

394

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

SciTech Connect

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 {mu}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.; Hernandez, R. [University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States); Fisher, R. K.; Jackson, G. L.; Pidcoe, S. V.; Taussig, D. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Lanctot, M. J. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Shankara, J. [Institute for Plasma Research, Bhat, Gandhinagar (India)

2011-11-15

395

X-ray and charged particle detection with CsI(Tl) layer coupled to a-Si:H photodiode layers  

SciTech Connect

A compact real-time X-ray and charged particle imager with digitized position output can built either by coupling a fast scintillator to a photodiode array or by forming one on a photodiode array directly. CsI(Tl) layers 100--1000{mu}m thick were evaporated on glass substrates from a crystal CsI(Tl). When coupled to a crystalline Si or amorphous silicon (a-Si:H) photodiode and exposed to calibrated X-ray pulses, their light yields and speed were found to be comparable to those of a crystal CsI(Tl). Single {beta} particle detection was demonstrated with this combination. The light spread inside evaporated CsI(Tl) was suppressed by its columnar structure. Scintillation detection gives much larger signals than direct X-ray detection due to the increased energy deposition in the detector material. Fabrication of monolithic type X-ray sensors consisting of CsI + a-Si:H photodiodes is discussed. 20 refs., 16 figs.

Fujieda, I.; Cho, G.; Drewery, J.; Gee, T.; Jing, T.; Kaplan, S.N.; Perez-Mendez, V.; Wildermuth, D. (Lawrence Berkeley Lab., CA (USA)); Street, R.A. (Xerox Palo Alto Research Center, CA (USA))

1990-10-01

396

Quantitative results in ultrasonic tomography of large objects using line sources and curved detector arrays.  

PubMed

A tomographic reconstruction technique valid for line sources, curved detector arrays, and large object is presented. For acquisitions involving a curved detector array, inverse diffraction is first used to propagate the field back to a straight line and then the standard filtered backpropagation (FBP) algorithm is employed to reconstruct the image. Using inverse diffraction the measured field can be accurately propagated all the way back to the reconstruction area. Thus an essential improvement is obtained compared to using the approximate backpropagation of Rytov data contained in the FBP algorithm, which becomes inaccurate when the distance from the measurement surface to the reconstruction area is large. This technique is applied to measured data and it is shown that it gives reconstructions of high quality, both with respect to geometry and velocity. It is also shown that, when the illuminating wave is cylindrical rather than plane, segmentation of the image can be used in combination with inverse diffraction and FBP reconstruction to obtain high-quality images of large objects. PMID:18267598

Sponheim, N; Gelius, L J; Johansen, I; Stamnes, J J

1991-01-01

397

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

PubMed

We demonstrate the principle applicability of antenna-coupled complementary metal oxide semiconductor (CMOS) field-effect transistor arrays as cameras for real-time coherent imaging at 591.4 GHz. By scanning a few detectors across the image plane, we synthesize a focal-plane array of 100×100 pixels with an active area of 20×20 mm2, which is applied to imaging in transmission and reflection geometries. Individual detector pixels exhibit a voltage conversion loss of 24 dB and a noise figure of 41 dB for 16 ?W of the local oscillator (LO) drive. For object illumination, we use a radio-frequency (RF) source with 432 ?W at 590 GHz. Coherent detection is realized by quasioptical superposition of the image and the LO beam with 247 ?W. At an effective frame rate of 17 Hz, we achieve a maximum dynamic range of 30 dB in the center of the image and more than 20 dB within a disk of 18 mm diameter. The system has been used for surface reconstruction resolving a height difference in the ?m range. PMID:22344098

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

2012-02-15

398

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

SciTech Connect

Purpose: To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. Methods: The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S{sub c,p}) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Results: Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 x 10 cm{sup 2} field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S{sub c,p} within 1.4% and 0.7% for 5 and 35 mm diameter cone, respectively. Furthermore, volume averaging of the IC can be observed for the 5 mm aperture where it differs by as much as 9.1% compared to the PSD measurement. The angular dependency of the UD is also observed, unveiled by an under-response around 2.5% of both 5 and 35 mm apertures. Conclusions: Output Factors and dose profiles measurements performed, respectively, with the PSD and the PSDCA were in agreement with those obtained with the UD and EBT2 films. For stereotactic radiosurgery treatment verification, the PSD gives accurate results compared to the planning system and the IC once the latter is corrected to compensate for the averaging effect of the IC. The PSD provides precise results when used as a single detector or in a dense array, resulting in a great potential for stereotactic radiosurgery QA measurements.

Gagnon, Jean-Christophe; Theriault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada)

2012-01-15

399

Ultrasound-assisted matrix solid phase dispersive extraction for the simultaneous analysis of ?-lactams (four penicillins and eight cephalosporins) in milk by high performance liquid chromatography with photodiode array detection.  

PubMed

The application of ultrasound-assisted matrix solid phase dispersive extraction for the confirmatory analysis of 12 ?-lactam antibiotics in milk by high performance liquid chromatography with photodiode array detection has been proposed herein. Four penicillins (cloxacillin, dicloxacillin, oxacillin, and amoxicillin) and eight cephalosporins (cefaclor, cefadroxil, ceftiofur, cefuroxime, cefoperazone, cefazolin, cephalexin, and cefotaxime) are effectively extracted using a mixed sorbent of Quick Easy Cheap Effective Rugged Safe technique and OASIS HLB providing a matrix free from any endogenous interference. Examined analytes were well resolved on an Inertsil ODS-3 analytical column with a mobile phase of CH(3)COONH(4) (0.05 M) and acetonitrile delivered under a gradient program. 1,7-Dimethyl-xanthine was used as internal standard. The method was validated meeting the European Legislation determining linearity, selectivity, stability, decision limit, detection capability, accuracy, precision, and ruggedness according to the Youden approach. Recoveries of all antibiotics rated from 85.0 to 115.7%, while RSD values were <12.7%. Finally, the method was successfully applied to milk samples purchased from local market. PMID:22941669

Karageorgou, Eftichia G; Samanidou, Victoria F; Papadoyannis, Ioannis N

2012-09-03

400

Monolithic planar InGaAs detector arrays for uncooled high-sensitivity SWIR imaging  

NASA Astrophysics Data System (ADS)

There are few choices when identifying detector materials for use in the SWIR wavelength band. We have exploited the direct-bandgap InGaAs material system to achieve superior room temperature (293°K) dark current. We have demonstrated sensitivity from 400nm through 2.6um with this material system and thus provide the opportunity to sense not only the visible, but also the J-band (1.25um), H-band (1.65um) and K-band (2.2um) windows. This paper discusses the advantages of our hybridized CMOS-InGaAs material system versus other potential SWIR material systems. The monolithic planar InGaAs detector array enables 100% fill factor and thus, high external quantum efficiency. We have achieved room-temperature pixel dark current of 2.8fA and shot noise of 110 electrons per pixel per second. Low dark current at +300K allows uncooled packaging options, affording the system designer dramatic reductions in size, weight (cameras <28grams), and power (<2.5W). Commercially available InGaAs pin arrays have shown diode lifetime mean time between failures (MTBF) of 1011hours for planar InGaAs detectors1, far exceeding telecom-grade reliability requirements. The use of a hybrid CMOS-InGaAs system allows best of breed materials to be used and permits efficient, cost-effective, volume integration. Moreover, we will discuss how the InGaAsP material system is compatible with CMOS monolithic integration. Taken together, these advantages, we believe, make InGaAs the obvious choice for all future SWIR systems.

Dixon, Peter; Masaun, Navneet; Evans, Michael; Ueng-McHale, John; Trezza, John; Ettenberg, Martin

2009-05-01

401

Development of linear array ROIC for InGaAs detector arrays with wavelength response to 2.5 microns for NIR spectroscopy and machine vision  

NASA Astrophysics Data System (ADS)

The design and development of a new, flexible, linear array readout integrated circuit (ROIC) for a new family of linear array detectors are described in this paper. The detector technology used is based on indium-gallium-arsenide (InGaAs) and includes low dark current versions with room temperature wavelength response cutoff of 1.7 microns and versions with altered stoichiometry to shift the room temperature absorbance cutoff wavelength to 2.55 microns. Discussion includes choice of features to cover many applications, testing methods, and evaluation of the first versions produced. The result will be a highly flexible linear array family, with versions matched to biological imaging, hot process inspection, pharmaceutical pill inspection, agricultural sorting and contaminant rejection, plastics recycling, moisture monitoring of continuous web processes.

Malchow, Douglas S.; Brubaker, Robert M.; Hansen, Marc P.

2008-05-01

402

Cryogenic SiGe ASICs for readout and multiplexing of superconducting detector arrays  

NASA Astrophysics Data System (ADS)

This paper presents an ultra low noise instrumentation based on cryogenic electronic integrated circuits (ASICs: Application Specific Integrated Circuits). We have designed successively two ASICs in standard BiCMOS SiGe 0.35 ?m technology that have proved to be operating at cryogenic temperatures. The main functions of these circuits are the readout and the multiplexing of TES/SQUID arrays. We report the cryogenic operation of a first ASIC version dedicated to the readout of a 2 × 4 pixel demonstrator array. We particularly emphasize on the development and the test phases of an ultra low white noise (0.2 nV/sqrtHz) cryogenic amplifier designed with two multiplexed inputs. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presented. We finally report on the development of a second version of this circuit to readout a 3 × 8 detectors array with improved noise performances and upgraded functionalities.

Sou, G.; Klisnick, G.; Redon, M.; Voisin, F.; Prêle, D.; Bréelle, E.; Piat, M.

2009-11-01

403

Cryogenic SiGe ASICs for readout and multiplexing of superconducting detector arrays  

NASA Astrophysics Data System (ADS)

This paper presents an ultra low noise instrumentation based on cryogenic electronic integrated circuits (ASICs : Application Specific Integrated Circuits). We have designed successively two ASICs in standard BiCMOS SiGe 0.35 ?m technology that have proved to be operating at cryogenic temperatures. The main functions of these circuits are the readout and the multiplexing of SQUID/TES arrays. We report the cryogenic operation of a first ASIC version dedicated to the readout of a 2×4 pixel demonstrator array. We particularly emphasize on the development and the test phases of an ultra low noise (0.2 nV/?Hz) cryogenic amplifier designed with two multiplexed inputs. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presented. We finally report on the development of a second version of this circuit to readout a 3×8 detectors array with improved noise performances and upgraded functionalities.

Voisin, F.; Pr"le, D.; Bréelle, E.; Piat, M.; Sou, G.; Klisnick, G.; Redon, M.

2008-08-01

404

LENDA: A low energy neutron detector array for experiments with radioactive beams in inverse kinematics  

NASA Astrophysics Data System (ADS)

The Low Energy Neutron Detector Array (LENDA) is a neutron time-of-flight (TOF) spectrometer developed at the National Superconducting Cyclotron Laboratory (NSCL) for use in inverse kinematics experiments with rare isotope beams. Its design has been motivated by the need to study the spin-isospin response of unstable nuclei using (p,n) charge-exchange reactions at intermediate energies (>100MeV/u). It can be used, however, for any reaction study that involves emission of low energy neutrons (150 keV to 10 MeV). The array consists of 24 plastic scintillator bars and is capable of registering the recoiling neutron energy and angle with high detection efficiency. The neutron energy is determined by the time-of-flight technique, while the position of interaction is deduced using the timing and energy information from the two photomultipliers of each bar. A simple test setup utilizing radioactive sources has been used to characterize the array. Results of test measurements are compared with simulations. A neutron energy threshold of <150keV, an intrinsic time (position) resolution of ˜ 400 ps (˜ 6 cm) and an efficiency >20% for neutrons below 4 MeV have been obtained.

Perdikakis, G.; Sasano, M.; Austin, Sam M.; Bazin, D.; Caesar, C.; Cannon, S.; Deaven, J. M.; Doster, H. J.; Guess, C. J.; Hitt, G. W.; Marks, J.; Meharchand, R.; Nguyen, D. T.; Peterman, D.; Prinke, A.; Scott, M.; Shimbara, Y.; Thorne, K.; Valdez, L.; Zegers, R. G. T.

2012-09-01

405

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

2008-08-01

406

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

NASA Astrophysics Data System (ADS)

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

Wang, Fei

2013-09-01

407

Switching with photodiodes  

NASA Astrophysics Data System (ADS)

The concept of optoelectronic switching is outlined, and its physical basis in photodiodes is explored. A model is developed for optoelectronic switching in p-i-n and avalanche photodiodes that agrees well with observed performance. Optoelectronic switches have demonstrated isolation is excess of 80 dB between 2 MHz and 1 GHz. The applications would range from large-scale switching of UHF or VHF signals (for example, in switched television distribution) to advanced signal routing applications in high-rate digital and high-capacity analog channels.

MacDonald, R. I.; Hara, E. H.

1980-03-01

408

Development of high-speed, low-noise NIR HgCdTe avalanche photodiode arrays for adaptive optics and interferometry  

NASA Astrophysics Data System (ADS)

The most promising way to overcome the CMOS noise barrier of infrared AO sensors is the amplification of the photoelectron signal directly at the point of absorption inside the infrared pixel by means of the avalanche gain. HgCdTe eAPD arrays with cut off wavelengths of ?c ~2.64 ?m produced by SELEX-Galileo have been evaluated at ESO. The arrays were hybridized to an existing non-optimized ROIC developed for laser gated imaging which has a format of 320×256 pixels and four parallel video outputs. The avalanche gain makes it possible to reduce the read noise to < 7 e rms. The dark current requirements of IR wavefront sensing are also met.

Finger, Gert; Baker, Ian; Dorn, Reinhold; Eschbaumer, Siegfried; Ives, Derek; Mehrgan, Leander; Meyer, Manfred; Stegmeier, Jörg

2010-07-01

409

Majo-ra-na: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements  

NASA Astrophysics Data System (ADS)

The Majo-ra-na collaboration will search for neutrinoless double-beta decay (0???) by fielding an array of high-purity germanium (HPGe) detectors in ultra-clean electroformed-copper cryostats deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, present exciting new techniques for identifying and reducing backgrounds to the 0??? signal. This should result in greatly improved sensitivity over previous generation experiments. The very low energy threshold attainable with PPC detectors also provides for a broader physics program including searches for dark matter and axions. The Majo-ra-na De-mon-strat-or is an R&D program that will field three ˜20 kg modules of PPC detectors at Sanford Underground Laboratory. Half of the detectors will be enriched to 86% in ^76Ge. Here, we will cover the motivation, design, recent progress and current status of this effort, with special attention to its physics reach. )

Gehman, Victor

2010-02-01

410

DETECTORS AND EXPERIMENTAL METHODS: Study of the characteristics of a scintillation array and single pixels for nuclear medicine imaging applications  

NASA Astrophysics Data System (ADS)

By using a pixelized Nal(Tl) crystal array coupled to a R2486 PSPMT, the characteristics of the array and of a single pixel, such as the light output, energy resolution, peak-to-valley ratio (P/V) and imaging performance of the detector were studied. The pixel size of the NaI(TI) scintillation pixel array is 2 mm×2 mm×5 mm. There are in total 484 pixels in a 22 × 22 matrix. In the pixel spectrum an average peak-to-valley ratio (P/V) of 16 was obtained. In the image of all the pixels, good values for the Peak-to-Valley ratios could be achieved, namely a mean of 17, a maximum of 45 and the average peak FWHM (the average value of intrinsic spatial resolution) of 2.3 mm. However, the PSPMT non-uniform response and the scintillation pixels array inhomogeneities degrade the imaging performance of the detector.

Zhu, Jie; Ma, Hong-Guang; Ma, Wen-Yan; Zeng, Hui; Wang, Zhao-Min; Xu, Zi-Zong

2009-04-01

411

Exploration of the metrological performance of a gas detector based on an array of unspecific infrared filters  

Microsoft Academic Search

The feasibility of a non-dispersive infrared (NDIR) gas detection system based on an array on non-specific detectors is studied in this work. The measurement system, that is intended to be low cost and of reduced dimension, is aimed to the simultaneous quantitative detection of different gases with IR absorption bands in the region of the 1000–4000cm?1. The detector is a

R. Rubio; J. Santander; J. Fonollosa; L. Fonseca; I. Gràcia; C. Cané; M. Moreno; S. Marco

2006-01-01

412

Neutron detection and multiplicity counting using a boron-loaded plastic scintillator\\/bismuth germanate phoswich detector array  

Microsoft Academic Search

Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator\\/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection (¹°B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where ³He proportional counters are

1998-01-01

413

Neutron detection and multiplicity counting using a boron-loaded plastic scintillator\\/bismuth germanate phoswich detector array  

Microsoft Academic Search

Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator\\/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection (10B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where 3He proportional counters are

Michael Conrad Miller

1997-01-01

414

The Arrayed Large-Area Dust Detectors in INterplanetray Space (ALADDIN) onboard the IKAROS solar sail demonstrator  

Microsoft Academic Search

In the summer of 2010, the world's first interplanetary solar sail demonstrator called the Inter-planetary Kite-craft Accelerated by the Radiation of the Sun (IKAROS) will be launched by an H-IIA rocket. On its thin sail membrane, a large-area but still light-weight dust detector made of 8 channels of 9-20 micron-thick PVDF films are attached. This detector is called the Arrayed

Hajime Yano; Makoto Tanaka; Chisato Okamoto; Makoto Tanak; Sunao Hasegawa; Makoto Tabata; Naoko Ogawa; Kyoko Okudaida; Takeo Iwai

2010-01-01

415

Silicon avalanche photodiodes developed at the Institute of Electron Technology  

NASA Astrophysics Data System (ADS)

Silicon avalanche photodiodes (APDs) -- due to the effect of avalanche multiplication of carriers in their structure -- are most sensitive and fastest detectors of visible and near infrared radiation. Also the value of noise equivalent power NEP of these detectors is the smallest. In the paper, the design, technology and properties of the silicon avalanche photodiodes with a n+ - p - ? - p+ epiplanar structure developed at the Institute of Electron Technology (ITE) are presented. The diameters of photosensitive area range from 0.3 mm to 5 mm. The ITE photodiodes are optimized for the detection of the 800 nm ÷ 850 nm radiation, but the detailed research on spectral dependencies of the gain and noise parameters has revealed that the spectral operating range of the ITE photodiodes is considerable wider and achieves 550 ÷ 1000 nm. These photodiodes can be used in detection of very weak and very fast optical signals. Presently in the world, the studies are carried out on applying the avalanche photodiodes in detection of X radiation and in the scintillation detection of nuclear radiation.

Wegrzecka, Iwona; Wegrzecki, Maciej; Bar, Jan; Grynglas, Maria; Uszynski, Andrzej; Grodecki, Remigiusz; Grabiec, Piotr B.; Krzeminski, Sylwester; Budzynski, Tadeusz

2004-07-01

416

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.

2011-10-01

417

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

418

3D scanning characteristics of an amorphous silicon position sensitive detector array system.  

PubMed

The 3D scanning electro-optical characteristics of a data acquisition prototype system integrating a 32 linear array of 1D amorphous silicon position sensitive detectors (PSD) were analyzed. The system was mounted on a platform for imaging 3D objects using the triangulation principle with a sheet-of-light laser. New obtained results reveal a minimum possible gap or simulated defect detection of approximately 350 ?m. Furthermore, a first study of the angle for 3D scanning was also performed, allowing for a broad range of angles to be used in the process. The relationship between the scanning angle of the incident light onto the object and the image displacement distance on the sensor was determined for the first time in this system setup. Rendering of 3D object profiles was performed at a significantly higher number of frames than in the past and was possible for an incident light angle range of 15 ° to 85 °. PMID:22418217

Contreras, Javier; Gomes, Luis; Filonovich, Sergej; Correia, Nuno; Fortunato, Elvira; Martins, Rodrigo; Ferreira, Isabel

2012-02-13

419

Status of the Germanium Detector Array (GERDA) in the search of neutrinoless ?? decays of 76Ge at LNGS  

NASA Astrophysics Data System (ADS)

The Germanium Detector Array (GERDA) in the search for neutrinoless ?? decays of 76Ge at LNGS will operate bare germanium diodes enriched in 76Ge in an (optional active) cryogenic fluid shield to investigate neutrinoless ?? decay with a sensitivity of T 1/2 > 2 × 1026 yr after an exposure of 100 kg yr. Recent progress includes the installation of the first underground infrastructures at Gran Sasso, the completion of the enrichment of 37.5 kg of germanium material for detector construction, prototyping of low-mass detector support and contacts, and front-end and DAQ electronics, as well as the preparation for construction of the cryogenic vessel and water tank.

Schönert, S.; Abt, I.; Altmann, M.; Bakalyarov, A. M.; Barabanov, I.; Bauer, C.; Bauer, M.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Bettini, A.; Bezrukov, L.; Brudanin, V.; Bolotsky, V. P.; Caldwell, A.; Cattadori, C.; Chirchenko, M. V.; Chkvorets, O.; Demidova, E.; di Vacri, A.; Eberth, J.; Egorov, V.; Farnea, E.; Gangapshev, A.; Gasparro, J.; Grabmayr, P.; Grigoriev, G. Y.; Gurentsov, V.; Gusev, K.; Hampel, W.; Heusser, G.; Heisel, M.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Jochum, J.; Junker, M.; Katulina, S.; Kiko, J.; Kirpichnikov, I. V.; Klimenko, A.; Knapp, M.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kröninger, K.; Kuzminov, V. V.; Laubenstein, M.; Lebedev, V. I.; Liu, X.; Majorovits, B.; Marissens, G.; Nemchenok, I.; Pandola, L.; Peiffer, P.; Pullia, A.; Alvarez, C. R.; Sandukovsky, V.; Scholl, S.; Schreiner, J.; Schwan, U.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stelzer, F.; Tikhomirov, A. V.; Tomei, C.; Ur, C. A.; Vasenko, A. A.; Vasiliev, S.; Weißhaar, D.; Wojcik, M.; Yanovich, E.; Yurkowski, J.; Zhukov, S. V.; Zocca, F.; Zuzel, G.

2006-12-01

420

Status of the Germanium Detector Array (GERDA) for the search of neutrinoless ?? decays of 76Ge at LNGS  

NASA Astrophysics Data System (ADS)

The Germanium Detector Array (GERDA) for the search of neutrinoless ?? decays of 76Ge at LNGS will operate bare germanium diodes enriched in 76Ge in an (optional active) cryogenic fluid shield to investigate neutrinoless ?? decay with a sensitivity of T>2×10 y after an exposure of 100 kg y. Recent progress includes the installation of the first underground infrastructures at Gran Sasso, the completion of the enrichment of 37.5 kg of germanium material for detector construction, the prototyping of the low-mass detector support and contacts, the front-end and DAQ electronics, as well as the preparation for construction of the cryogenic vessel and water tank.

Schonert, S.; GERDA Collaboration

2006-07-01

421

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

422

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

NASA Astrophysics Data System (ADS)

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

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

2004-05-01

423

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.

Desai, Ravi; Yang, Michael; Sniadecki, Nathan; Legant, Wesley; Chen, Christopher

2007-01-01

424

Geant4 simulations for the Versatile Array of Neutron Detectors at Low Energies (VANDLE)  

NASA Astrophysics Data System (ADS)

The Versatile Array of Neutron Detectors at Low Energies (VANDLE) (En circa 100keV - 10 MeV) has been proposed to study the structure of exotic nuclei with low-energy radioactive ion beams from the Holifield Radioactive Ion Beam Facility (HRIBF) at the Oak Ridge National Laboratory (ORNL). The VANDLE array is highly modular based on bars of scintillator allowing the configuration of the individual elements to be optimized for particular experimental requirements. Proposed experiments include (d,n) reactions and beta-delayed neutron emission studies relevant to nuclear astrophysics. Simulations performed using the GEANT4 toolkit are in progress in order to achieve the best configuration: to cover a large solid angle, to have an optimal position resolution and high efficiency. The GEANT4 simulations are presently being