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1

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

2

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

3

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

4

Signal and Noise Characteristics Induced by Unattenuated X Rays from a Scintillator in Indirect-Conversion CMOS Photodiode Array Detectors  

Microsoft Academic Search

We report the measurement results of signal and noise characteristics induced by the direct x-rays in an indirect-conversion CMOS photodiode array detector. In order to isolate the signal and noise due to the direct x-rays from those due to the optical photons, we inserted a light-absorbing blackout material between a phosphor screen and the photodiode array. From the images irradiated

Seungman Yun; Ho Kyung Kim; Chang Hwy Lim; Min Kook Cho; Thorsten Achterkirchen; Ian Cunningham

2009-01-01

5

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

6

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

7

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

8

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

9

Radiation Effects on the Performance of CMOS Photodiode Array Detectors and the Role of Gain-Offset Corrections  

Microsoft Academic Search

We report the observation of performance degradation in a detector consisting of a phosphor screen and a CMOS (complementary metal-oxide-semiconductor) photodiode array under the continuous irradiation of 45-kVp x-rays. The performance was assessed in terms of dark pixel signal, dynamic range, modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). From the measurement results, it has been observed

Ho Kyung Kim; Min Kook Cho; Thorsten Achterkirchen; Wonho Lee

2009-01-01

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

Avalanche Photodiode Arrays for Optical Communications Receivers  

NASA Technical Reports Server (NTRS)

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

Srinivasan, M.; Vilnrotter, V.

2001-01-01

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

Design and Evaluation of a 2D Array PIN Photodiode Bump Bonded to Readout IC for the Low Energy X-ray Detector  

Microsoft Academic Search

A 2D array radiation sensor, consisting of an array of PIN photodiodes bump bonded to readout integrated circuit (IC), has been developed for operation with low energy X-rays. The PIN photodiode array and readout IC for this system have been fabricated. The main performance measurements are the following: a few pA-scale leakage current, 350 pF junction capacitance, 30 mum-depth depletion

Sunwoo Yuk; Shin-Woong Park; Yun Yi

2006-01-01

14

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)] [Radiation Monitoring Devices, Inc., Watertown, MA (United States); Sdrulla, D. [Advanced Power Technology, Bend, OR (United States)] [Advanced Power Technology, Bend, OR (United States)

1998-06-01

15

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

16

High-power flip-chip mounted photodiode array.  

PubMed

Four-element modified uni-traveling-carrier (MUTC) photodiode arrays (PDA) flip-chip bonded onto transmission lines on AlN substrates are demonstrated. High RF output powers of 26.2 dBm and 21.0 dBm are achieved at 35 GHz and 48 GHz, respectively, using a PDA with 28-?m diameter photodiodes. A systematic comparison between a PDA with four 20 ?m-diameter elements and a discrete detector with the same active area (40-?m diameter) is presented. The PDA achieved higher output power and thermal dissipation compared to its discrete counterpart. PMID:23609702

Cross, Allen S; Zhou, Qiugui; Beling, Andreas; Fu, Yang; Campbell, Joe C

2013-04-22

17

CdZnTe photodiode arrays for medical imaging  

SciTech Connect

In this paper, we report on the design, fabrication, and performance of the first CdZnTe Schottky photodiode arrays for radiation detection. High pressure Bridgman-grown CdZnTe substrates with bulk resistivities in the range 10{sup 8} to 10{sup 10} ohm-cm were used. CdZnTe Schottky photodiodes were formed with In and Ti/Au contacts. Diode arrays with pixel sizes from 1000 x 1000 {mu}m to 100 x 100 {mu}m were fabricated. The diode`s I-V characteristics exhibited low leakage current and high bulk resistivity; leakage current decreased as diode pixel size was reduced. Response of these detector arrays to high energy photons was uniform and their energy resolution improved with smaller pixel size. 14 refs., 9 figs.

Sudharsanan, R.; Parodos, T.; Karam, N.H. [Spire Corporation, Bedford, MA (United States); Ruzin, A.; Nemirovsky, Y. [Technion-Israel Inst. of Technology, Haifa (Israel)

1996-08-01

18

Current isolating epitaxial buffer layers for high voltage photodiode array  

DOEpatents

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

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

2002-01-01

19

Determining the pharmacokinetics of psilocin in rat plasma using ultra-performance liquid chromatography coupled with a photodiode array detector after orally administering an extract of Gymnopilus spectabilis.  

PubMed

This study established ultra-performance liquid chromatography coupled with a photodiode array detector for determining psilocin and its pharmacokinetics in rat plasma after orally administering an extract of Gymnopilus spectabilis. The extract was separated on an ODS C18 column (2.3 ?m, 100 mm × 2.1 mm I.D.) by gradient elution with (A) water containing 50mM AcONH(4) and (B) acetonitrile. The wavelength was set at 265 nm and the injection volume was 10 ?L. Under these conditions, the calibration curve was linear over the concentration range 0.2-20 ?g/mL with a correlation coefficient of r(2)=0.9992. The inter- and intraday precision levels were less than 7% and the accuracies (%) were within the range 92.0-102.5%. The method was sufficiently valid to be applied to a pharmacokinetics study of psilocin in rat plasma. The pharmacokinetic parameters of psilocin in rat plasma after the oral administration of a G. spectabilis extract were as follows: C(max), 0.43 ± 0.12 ?g/mL; T(max), 90 ± 2.1 min; AUC(0?t), 1238.3 ± 96.4 (?g/mL) min; and T(1/2), 117.3 ± 40.3 min. PMID:21820980

Chen, Jianbo; Li, Meijia; Yan, Xitao; Wu, Enqi; Zhu, Hongmei; Lee, Kwan Jun; Chu, Van Men; Zhan, Lifeng; Lee, Wonjae; Kang, Jong Seong

2011-09-01

20

Quantitative determination of usnic acid in Usnea lichen and its products by reversed-phase liquid chromatography with photodiode array detector.  

PubMed

Usnic acid, a lichen substance, has a wide range of pharmaceutical applications, including antibiotic, antimycotic, antifeedant, antitubercular, antitumor, and analgesic activities. Some products containing usnic acid are marketed as weight control supplements; however, hepatotoxicity and acute liver failures were reported as severe side effects. The usnic acid content present in the plant materials and market products was analyzed by reversed-phase high-pressure liquid chromatography with a photodiode array detector at 233 nm. A Waters XTerra RP18 (150 x 4.6 mm; 5 microm particle size) column was the stationary phase; mobile phase was aqueous 0.1% acetic acid and acetonitrile gradient at flow rate of 1.0 mL/min. The temperature was held constant at 30 degrees C. The retention time of usnic acid was approximately 13.3 min. Acetone extraction of the samples took place with sonication. The precision of the method was confirmed by a standard deviation below 3.0% (n=3) and usnic acid recovery was 99.0%. Limit of detection was 0.4 microg/mL and the response was linear from 1.4 to 570.0 microg/mL with a correlation coefficient (R2) of 0.9991. The content of usnic acid in 4 raw materials and 22 finished products was analyzed. PMID:16385974

Ji, Xiuhong; Khan, Ikhlas A

2005-01-01

21

High gain avalanche photodiode arrays for DIRC applications  

SciTech Connect

The detection of light emitted in Cherenkov radiators 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 the performance of a new, Geiger mode operated, silicon micro-avalanche photodiode ({micro}APD) array, designed for Cherenkov light imaging applications. They address issues of optical interfacing, speed, and pulse spectra achievable with these {micro}APDs. The new {micro}APD array provides a high sensitivity detector for applications requiring two dimensional light mapping with single photon sensitivity. These features make it a promising candidate for the detection of Cherenko light in modern high energy physics experiments.

Vasile, S.; Shera, S.; Shamo, D.; Squillante, M.R. [Radiation Monitoring Devices, Inc., Watertown, MA (United States)] [Radiation Monitoring Devices, Inc., Watertown, MA (United States); Wilson, R.J. [Colorado State Univ., Fort Collins, CO (United States)] [Colorado State Univ., Fort Collins, CO (United States)

1999-08-01

22

ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays  

NASA Technical Reports Server (NTRS)

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

Vasile, Stefan; Lipson, Jerold

2012-01-01

23

Rapid determination of the ratios of three aromatic residues in peptides by reversed-phase high-performance liquid chromatography with a high-resolution photodiode-array detector.  

PubMed

A method for the simultaneous determination of the ratios of three aromatic residues in peptides by derivative UV spectrophotometry on a spectrophotometer with a resolution of 0.1 nm can be used for the RP-HPLC analysis of peptides because of the recent development of high-resolution photodiode-array detectors (1.2 nm). The difference between the theoretical and experimental ratios of aromatic residues of peptides determined in real time is less than 5%. This method could become a powerful tool for the study of peptides and hydrolysates: A variety of possible applications are discussed. PMID:7757235

Perrin, E; Miclo, L; Driou, A; Linden, G

1995-02-01

24

Photodecomposition of o-phthaldialdehyde-derivatized amino acids by the photodiode array detector during their high-performance liquid chromatographic analysis.  

PubMed

During the high-performance liquid chromatographic (HPLC) analysis of o-phthaldialdehyde (OPA)-derivatized amino acids such as arginine and homoarginine, we observed that the response of the fluorescence detection (FLD) system is decreased when the photodiode array detection (DAD) system (located before the FLD system) was simultaneously switched on. The decrease in the FLD response, i.e., the difference in the FLD peak area (DeltaA) obtained with DAD modes off (A(off)) and on (A(on)) was dependent upon the flow rate, but the relative FLD response decrease (DeltaA/A(off)) was practically independent of the amount of analyte injected. For example, decreasing the flow rate from 1 to 0.5 mL/min resulted in the relative decrease of FLD response from approximately 5% to 11%. It was concluded that DAD caused a photoinduced partial decomposition of the OPA-derivatized amino acids flowing through the cell. The photoinduced dissociation of OPA derivatives was independently supported by using off-line photodiode array spectrometric measurements with long and short irradiation pulses. Based on the experimental results, for description of the variation of FLD responses with the flow rate upon the irradiation by DAD a simple mathematical model is proposed and reported. PMID:18302962

Kéki, Sándor; Török, János; Biri, Bernadett; Zsuga, Judit; Gesztelyi, Rudolf; Bereczki, Dániel; Zsuga, Miklós

2008-03-28

25

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

26

UV photodetectors, focal plane arrays, and avalanche photodiodes  

NASA Astrophysics Data System (ADS)

The study of III-Nitride based optoelectronics devices is a maturing field, but there are still many underdeveloped areas in which to make a contribution of new and original research. This work specifically targets the goals of realizing high-efficiency back-illuminated solar-blind photodetectors, solar-blind focal plane arrays, and visible- and solar-blind Avalanche photodiodes. Achieving these goals has required systematic development of the material growth and characterization, device modeling and design, device fabrication and processing, and the device testing and qualification. This work describes the research conducted and presents relevant devices results. The AlGaN material system has a tunable direct bandgap that is ideally suited to detection of ultraviolet light, however this material system suffers from several key issues, making realization of high-efficiency photodetectors difficult: large dislocation densities, low n-type and p-type doping efficiency, and lattice and thermal expansion mismatches leading to cracking of the material. All of these problems are exacerbated by the increased aluminum compositions necessary in back-illuminated and solar-blind devices. Overcoming these obstacles has required extensive development and optimization of the material growth techniques necessary: this includes everything from the growth of the buffer and template, to the growth of the active region. The broad area devices realized in this work demonstrate a quantum efficiency that is among the highest ever reported for a back-illuminated solar-blind photodetector (responsivity of 157 mA/W at 280nm, external quantum efficiency of 68%). Taking advantage of the back illuminated nature of these detectors, we have successfully developed the technology to hybridize and test a solar-blind focal plane array camera. The initial focal plane array shows good uniformity and reasonable operability, and several images from this first camera are presented. However, in order to improve the performance of these devices to the point where they can effectively compete with photo-multiplier tube technology, it is necessary to develop devices with internal gain. To this end GaN and AlGaN based avalanche photodiodes have been studied, and we report the first realization of a solar-blind back-illuminated avalanche photodiode. The next logical step is to continue this work and realize Geiger mode avalanche photodiodes capable of single photon detection.

McClintock, Ryan

27

A Linear Photodiode Array Employed in a Short Range Laser Triangulation Obstacle Avoidance Sensor.  

National Technical Information Service (NTIS)

An opto-electronic receiver incorporating a multi-element linear photodiode array as a component of a laser-triangulation rangefinder was developed as an obstacle avoidance sensor for a Martian roving vehicle. The detector can resolve the angle of laser r...

J. P. Odenthal

1980-01-01

28

Quality evaluation of Hypericum japonicum by using high-performance liquid chromatography coupled with photodiode array detector and electrospray ionization tandem mass spectrometry.  

PubMed

A high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (HPLC-PAD-ESI-MS(n)) method was developed to evaluate the quality of Hypericum japonicum through establishing chromatographic fingerprint and simultaneous determination of seven phenolic compounds. The analysis was achieved on an Ultimate XB-C(18) analytical column (250 mm x 4.6 mm i.d., 5 microm) using an aqueous solution of acetic acid (pH 3.8) and methanol as the mobile phase. Ten samples of H. japonicum from various habitats were investigated and the correlation coefficients of similarity were determined from the HPLC fingerprints. By using an online ESI-MS(n), 20 common peaks in chromatographic fingerprints were identified as phenols, including flavones and their glycosides, flavonones and their glucosides, flavanols, xanthones, phloroglucinols, phenyl propanoids and chromones. Based on the above study, seven phenols which are considered to be major constituents in H. japonicum, including 3,4-dihydroxybenzoic acid (1), taxfolin-7-O-alpha-L-rhamnoside (7), 7-dihydroxy-2-(1-methylpropyl)chromone-8-beta-D-glucoside (8), isoquercitrin (14), quercitrin (16), quercetin-7-O-alpha-L-rhamnoside (18) and quercetin (19) were quantified by the validated HPLC-PAD method. This developed method by combination of chromatographic fingerprint and quantification analysis could be applied to control the quality of H. japonicum. PMID:19358152

Gao, Wei-Na; Luo, Jian-Guang; Kong, Ling-Yi

2009-09-01

29

Photodiode  

NSDL National Science Digital Library

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

Van Zeghbroeck, Bart J.

2011-07-04

30

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

PubMed

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

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

2013-01-01

31

A validated stability-indicating HPLC with photodiode array detector (PDA) method for the stress tests of Monascus purpureus-fermented rice, red yeast rice.  

PubMed

A stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detection method was developed and validated for the assay of monacolin series compounds including monacolin K, L, J and their hydroxyl acid forms as well as dehydroxymonacolin K simultaneously in Monascus purpureus-fermented rice, red yeast rice. Well-resolved peaks of seven main compounds of monacolin family were profiled on a C(18) reverse-phase column using a linear gradient of 0.1% trifluoroacetic acid and acetonitrile as the mobile phase, and the detection wavelength was set at 237nm. The method was validated with respect to specificity, chromatographic parameters, linearity, precision, accuracy, limits of detection and quantitation. The stability stress testing for fermented red yeast rice powder was carried out to show the effects of high temperature (80 degrees C), high humidity at room temperature (92.5% RH, 25 degrees C), high humidity at high temperature (75% RH, 60 degrees C) and light (sunlight) in solid state. The results exhibited that monacolins decreased significantly under the conditions of high humidity at high temperature (75% RH, 60 degrees C) and sunlight. Monacolin K and its hydroxyl acid form would be dehydrolyzed and turned to dehydromonacolin K at high temperature (80 degrees C) while the monacolin K, J and L would be transformed into their corresponding hydroxyl acid forms under the condition of high humidity (92.5% RH, 25 degrees C). The indication is that monacolins in red yeast rice powder are light-sensitive and thermal-sensitive. Therefore, it has been suggested that the preparations containing monacolins be stored in the place of cool and lightproof. The proposed degradation pathways were discussed as well. The multi-components assay for stability of botanical products could provide much more information than the normal marker-orientation method. PMID:15876509

Li, Yong-Guo; Liu, Hong; Wang, Zheng-Tao

2005-09-01

32

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

33

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

2011-01-01

34

Effect of a polywell leometry on a CMOS photodiode array  

Microsoft Academic Search

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

Paul V. Jansz; Steven Hinckley; Graham Wild

2010-01-01

35

Effect of a Polywell geometry on a CMOS Photodiode Array  

Microsoft Academic Search

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

Paul V Jansz; Steven Hinckley; Graham Wild

2010-01-01

36

Silicon avalanche photodiodes for particle detector:. modelling and fabrication  

NASA Astrophysics Data System (ADS)

Large-area arrays (30×30) of metal/resistive layer/silicon (MRS) avalanche photodiodes as 150×150 ?m sub-pixels were developed and fabricated to detect short-wavelength scintillator signals for high-energy particle detection. Modelling of MRS photodiodes was performed using McIntyre's approach of local electric field to optimize semiconductor doping profiles and resistive layer parameters and to obtain the minimum value of effective k-factor (the holes to electrons ionization coefficients ratio) less than 0.01 under low excess noise factor and high gain. The resistive layer/silicon surface barrier suppresses minority carriers injection to decrease dark current and effective k-factor. Test samples of silicon avalanche photodiodes arrays have been fabricated using low-rate epitaxial growth of silicon layer, impurity doping, and resistive layer deposition processing. The integral gain for experimental specimens was ˜100.

Khodin, Alexandre; Shvarkov, Dmitry; Zalesski, Valery

2001-06-01

37

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

2014-03-01

38

Characterization and identification of the chemical constituents from tartary buckwheat (Fagopyrum tataricum Gaertn) by high performance liquid chromatography/photodiode array detector/linear ion trap FTICR hybrid mass spectrometry.  

PubMed

In recent years tartary buckwheat has become popular healthful food due to its antioxidant, antidiabetic and antitumor activities. However, its chemical constituents have not yet been fully characterized and identified. In this paper, a novel high performance liquid chromatography coupled with photodiode array detector and linear ion trap FTICR hybrid mass spectrometry (HPLC-PDA/LTQ-FTICRMS) method was established to characterize and identify a total of 36 compounds by a single run. The retention time, maximum UV absorption wavelength, accurate mass weight and characteristic fragment ions were collected on line. To confirm the structures, 11 compounds were isolated and identified by MS and NMR experiments. 1, 3, 6, 6'-tetra-feruloyl sucrose named taroside was a new phenlypropanoid glycoside, together with 3, 6-di-p-coumaroyl-1, 6'-di-feruloyl sucrose, 1, 6, 6'-tri-feruloyl-3-p-coumaroyl sucrose, N-trans-feruloyltyramine and quercetin-3-O-[?-D-xyloxyl-(1?2)-?-L-rhamnoside] were isolated for the first time from the Fagopyrum species. The research enriched the chemical information of tartary buckwheat. PMID:23194538

Ren, Qiang; Wu, Caisheng; Ren, Yan; Zhang, Jinlan

2013-02-15

39

Biostability of micro-photodiode arrays for subretinal implantation.  

PubMed

Micro-photodiode arrays based on semiconductor chip technology are being developed to replace degenerated photoreceptor cells in the retina. Electric current is generated in tiny micro-photodiodes and delivered to the adjacent tissue by micro-electrodes. One of the main requirements of a sub-retinal implantable device is long-term stability versus corrosion in vivo (biostability). Biostability of micro-photodiode arrays (MPDA) was investigated in vitro and in vivo. No significant damage was found on chips immersed for up to 21 months in saline solution. Under in vivo conditions, however, the silicon oxide passivation layer of the chip was dissolved within a period of about 6-12 months. Subsequently, the underlying silicon was corroded. In contrast, stimulation electrodes consisting of titanium nitride were well preserved both in vitro and in vivo. The deterioration of the electrical properties of the micro-photodiodes correlated with the morphological damage observed. Strategies aiming at the development of an improved biostable encapsulation of neurotechnological implants have to be investigated and will be discussed briefly. PMID:11771699

Hämmerle, Hugo; Kobuch, Karin; Kohler, Konrad; Nisch, Wilfried; Sachs, Helmut; Stelzle, Martin

2002-02-01

40

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

SciTech Connect

We present measurements of a 4 element PET detector module that uses a 2{times}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{times}3{times}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 {open_quotes}lossy{close_quotes} 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{degrees}C with a photodiode amplifier peaking time of 2 {mu}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)

1994-11-01

41

Large-Format AlGaN PIN Photodiode Arrays for UV Images  

NASA Technical Reports Server (NTRS)

A large-format hybridized AlGaN photodiode array with an adjustable bandwidth features stray-light control, ultralow dark-current noise to reduce cooling requirements, and much higher radiation tolerance than previous technologies. This technology reduces the size, mass, power, and cost of future ultraviolet (UV) detection instruments by using lightweight, low-voltage AlGaN detectors in a hybrid detector/multiplexer configuration. The solar-blind feature eliminates the need for additional visible light rejection and reduces the sensitivity of the system to stray light that can contaminate observations.

Aslam, Shahid; Franz, David

2010-01-01

42

Organic light detectors: photodiodes and phototransistors.  

PubMed

While organic electronics is mostly dominated by light-emitting diodes, photovoltaic cells and transistors, optoelectronics properties peculiar to organic semiconductors make them interesting candidates for the development of innovative and disruptive applications also in the field of light signal detection. In fact, organic-based photoactive media combine effective light absorption in the region of the spectrum from ultraviolet to near-infrared with good photogeneration yield and low-temperature processability over large areas and on virtually every substrate, which might enable innovative optoelectronic systems to be targeted for instance in the field of imaging, optical communications or biomedical sensing. In this review, after a brief resume of photogeneration basics and of devices operation mechanisms, we offer a broad overview of recent progress in the field, focusing on photodiodes and phototransistors. As to the former device category, very interesting values for figures of merit such as photoconversion efficiency, speed and minimum detectable signal level have been attained, and even though the simultaneous optimization of all these relevant parameters is demonstrated in a limited number of papers, real applications are within reach for this technology, as it is testified by the increasing number of realizations going beyond the single-device level and tackling more complex optoelectronic systems. As to phototransistors, a more recent subject of study in the framework of organic electronics, despite a broad distribution in the reported performances, best photoresponsivities outperform amorphous silicon-based devices. This suggests that organic phototransistors have a large potential to be used in a variety of optoelectronic peculiar applications, such as a photo-sensor, opto-isolator, image sensor, optically controlled phase shifter, and opto-electronic switch and memory. PMID:23483718

Baeg, Kang-Jun; Binda, Maddalena; Natali, Dario; Caironi, Mario; Noh, Yong-Young

2013-08-21

43

Integrated hydrogenated amorphous Si photodiode detector for microfluidic bioanalytical devices.  

PubMed

Hydrogenated amorphous silicon (a-Si:H) PIN photodiodes have been developed and characterized as fluorescence detectors for microfluidic analysis devices. A discrete a-Si:H photodiode is first fabricated on a glass substrate and used to detect fluorescent dye standards using conventional confocal microscopy. In this format, the limit of detection for fluorescein flowing in a 50-microm deep channel is 680 pM (S/N = 3). A hybrid integrated detection system consisting of a half-ball lens, a ZnS/YF3 multilayer optical interference filter with a pinhole, and an annular a-Si:H photodiode is also developed that allows the laser excitation to pass up through the central aperture in the detector. Using this integrated detection device, the limit of detection for fluorescein is 17 nM, and DNA fragment sizing and chiral analysis of glutamic acid are successfully performed. The a-Si:H detector exhibits high sensitivity at the emission wavelengths of commonly used fluorescent dyes and is readily microfabricated and integrated at low cost making it ideal for portable microfluidic bioanalyzers and emerging large scale integrated microfluidic technologies. PMID:14710806

Kamei, Toshihiro; Paegel, Brian M; Scherer, James R; Skelley, Alison M; Street, Robert A; Mathies, Richard A

2003-10-15

44

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

45

Thin photodiodes for a scintillation-silicon well detector  

SciTech Connect

In developing position sensitive radiation sensors, e.g., for medical imaging, low-gain silicon well sensors were made for the detection of scintillation light. The 3 x 3 arrays induce N++NP diodes, processed in the {approximately}12 {micro}m thick membranes that remain after thinning of 530 {micro}m thick (100) silicon wafers by means of a potassium hydroxide (KOH) solution. A comparison is made for the light detection efficiency of these diodes with that of a 500 {mu}m thick PIN photodiode.

Allier, C.P.; Hollander, R.W.; Sarro, P.M.; Eijk, C.W.E. van

1999-12-01

46

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

47

High resolution, low energy avalanche photodiode X-ray detectors  

NASA Technical Reports Server (NTRS)

Silicon avalanche photodiodes have been fabricated, and their performance as X-ray detectors has been measured. Photon sensitivity and energy resolution were measured as a function of size and operating parameters. Noise thresholds as low as 212 eV were obtained at room temperature, and backscatter X-ray fluorescence data were obtained for aluminum and other light elements. It is concluded that the results with the X-ray detector are extremely encouraging, and the performance is challenging the best available proportional counters. While not at the performance level of either cryogenic silicon or HgI2, these device operate at room temperature and can be reproduced in large numbers and with much larger areas than typically achieved with HgI2. In addition, they are rugged and appear to be indefinitely stable.

Farrell, R.; Vanderpuye, K.; Entine, G.; Squillante, M. R.

1991-01-01

48

Nano-Multiplication-Region Avalanche Photodiodes and Arrays  

NASA Technical Reports Server (NTRS)

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

Zheng, Xinyu; Pain, Bedabrata; Cunningham, Thomas

2008-01-01

49

Maia X-ray Microprobe Detector Array System  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

50

Calibration of a Photodiode Array Spectrometer Against the Copper Point  

NASA Astrophysics Data System (ADS)

This paper describes a method to calibrate photodiode array spectrometers in the spectral radiance mode using a fixed-point blackbody as a reference source. Fixed-point blackbodies are characterized by their excellent emissivity, uniformity, and stability, which make them superior to both conventional standard lamps and variable temperature blackbodies. The temperature of these fixed points is accurately determined being traceable to either the International Temperature Scale (ITS-90) or thermodynamically through radiometric standards. The potential advantage of the fixed-point traceability chain is that it can be universally reproduced without recourse to any hierarchical calibrations or standards. The paper presents the calibration system and discusses the limitations of such an approach. The method used obtained an uncertainty of around 1.4 % (k = 2 ) associated with radiance responsivity across the spectral region from 550 nm to 1050 nm, which is comparable to what is readily achieved with a lamp-tile or lamp-illuminated spherical source.

Salim, S. G. R.; Woolliams, E. R.; Fox, N. P.

2014-05-01

51

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

52

Continuous multicomponent stack gas analyzer using ultraviolet-photodiode-array spectroscopy  

NASA Astrophysics Data System (ADS)

Ammonia injection is frequently used to reduce emissions of nitrogen oxides from modern combustion plant. Accurate measurements of ammonia and nitric oxide are therefore required to ensure optimum operation of the NOx control system. Measurements of sulphur dioxide are also required to ensure compliance with legislation in most countries. An extractive analytical system has been developed for continuous measurements of ammonia, nitric oxide and sulphur dioxide concentrations in stack gases based on an ultraviolet spectrometer using a photodiode array detector operating in the 200nm region. The use of the photodiode array spectrometer enables the system to have a fast response time while maintaining excellent wavelength stability and reliability, since there are no moving parts in the main optical system. A high temperature sampling system is coupled to a hot sample cell to ensure that there is no degradation of the sample prior to measurement. Tests in the laboratory and at a combustion plant in Europe have shown practical detection limits of 1ppm for all of the target gases.

Stuart, Derek D.

1997-05-01

53

Nano-multiplication region avalanche photodiodes and arrays  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

54

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

55

Photoelectron counting with an image intensifier tube and a self-scanned photodiode array  

NASA Technical Reports Server (NTRS)

A self-scanned photodiode array was fiber-optically coupled to an ITT proximity-focused image intensifier tube. It was determined that a single photoelectron event produces 34,000 charge carriers in a photodiode. This charge is only a factor of 2.8 above the rms noise level of the preamplifier used in the tests, but standard charge-sensitive techniques are at least a factor of 12 better. The image tube and photodiode array combination can be packaged in a disk 5.1 cm in diameter and 2.6 cm thick.

Sandel, B. R.; Broadfoot, A. L.

1976-01-01

56

Photoelectron counting with an image intensifier tube and a self-scanned photodiode array.  

PubMed

A self-scanned photodiode array was fiber-optically coupled to an ITT proximity-focused image intensifier tube. It was determined that a single photoelectron event produces 3.4 x 10(4) charge carriers in a photodiode. This charge is only a factor of 2.8 above the rms noise level of the preamplifier used in the tests, but standard charge-sensitive techniques are at least a factor of 12 better. The image tube and photodiode array combination can be packaged in a disk 5.1 cm in diameter and 2.6 cm thick. PMID:20168400

Sandel, B R; Broadfoot, A L

1976-12-01

57

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=2039 keV, 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?1026 y; this corresponds to an effective Majorana mass range from 0.1 eV to 0.2 eV.

Jochum, J.

2010-04-01

58

Solid state neutron detector array  

DOEpatents

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

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

1999-01-01

59

Solid state neutron detector array  

DOEpatents

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

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

1999-08-17

60

Spectral correction of silicon photodiode solar radiation detectors  

SciTech Connect

The multi-filter rotating shadowband radiometer (MFRSR) is a ground- based instrument that uses a silicon photodiode sensor to measure shortwave global and diffuse horizontal irradiance from which direct normal irradiance is calculated. Besides this multiplexing advantage, silicon sensors are rugged, stable and have a fast time response. On the other hand, silicon sensors are both thermally and spectrally sensitive. They, as do all pyranometric sensors, have an imperfect cosine response, especially at high solar-zenith angles. In the MFRSR two of these problems are solved. The MFRSR`s cosine response is measured and corrected. An automatic heater maintains the MFRSR detector at a constant temperature near 40 {degree}C. This paper describes a correction scheme, based on sky conditions, to account for the remaining spectral bias. The data base for these corrections was collected in Albany, New York, during 1993. The MFRSR and WMO firstclass thermopile instruments were sampled every 15 seconds and 5- minute averages were compared. The differences in time response between silicon and thermopile instruments contributes substantially to the remaining root-mean-square error reported.

Zhou, C.; Michalsky, J.

1994-12-31

61

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

PubMed

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

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

2012-03-01

62

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

63

Characterization of avalanche photodiodes for lidar atmospheric return signal detectors  

NASA Technical Reports Server (NTRS)

Results are presented from tests to characterize noise, dark current, overload, and gain versus bias, relationships of ten avalanche photodiodes. The advantages of avalanche photodiodes over photomultiplier tubes for given laser wavelengths and return signal amplitudes are outlined. The relationship between responsivity and temperature and dark current and temperature are examined. Also, measurements of the noise equivalent power, the excess noise factor, and linearity are given. The advantages of using avalanche photodiodes in the Lidar Atmospheric Sensing Experiment and the Lidar In-Space Technology Experiment are discussed.

Antill, C. W., Jr.; Holloway, R. M.

1988-01-01

64

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

65

Type II indium arsenide/gallium antimonide superlattice photodiodes and infrared focal plane arrays  

NASA Astrophysics Data System (ADS)

In this work, the Type II InAs/GaSb binary superlattices have been exploited particularly for photodiodes and their applications to focal plane arrays (FPAs). Empirical tight-binding method (ETBM) was developed to guide the superlattice design. Close matching between the theoretical predictions and experimental measurements was observed. Some of the critical growth parameters have been optimized and the material quality of the superlattices has been improved significantly. The surface roughness of finished detectors surface has reached 1.2-1.4 A over an area of 20 mumx20 mum, and around 1.0 A over an area of 5 mumx5 mum and below. The x-ray full width half maximum (FWHM) has been decreased to values below 20 arcsec, for both the center and the satellite peaks. High performance photodiodes with cutoff wavelength around 5 mum, 7-8 mum, 18.8 mum, and 32 mum have been demonstrated. With the highly reproducible results, the world's first 256x256 Type II FPAs with cutoff wavelength around 8 mum were concept proved. Afterwards, uncooled FPAs with cutoff wavelength around 5 mum using a same format were first demonstrated in this material system. The application of the SUMO cells for indium and gallium, and the cracker cells for arsenic and antimony has greatly improved the growth uniformity and repeatability. My invention of the GaxIn1-x mixed interface engineering technique has solved the lattice mismatch problem for these superlattices in the mid to long wavelength infrared range. It also enables very short period superlattice in the longer wavelength range. For the focal plane arrays, I also developed the etching stop techniques using InAs0.9107Sb0.0893. Material growth of AlAs0.0832 Sb0.9168 was also studied for both etching stop technique and for hetero structure designs.

Wei, Yajun

66

Advanced UV Detectors and Detector Arrays  

NASA Technical Reports Server (NTRS)

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

Pankove, Jacques I.; Torvik, John

1998-01-01

67

A microwave detector based on an MCT photodiode for subthermonuclear plasma research  

Microsoft Academic Search

A microwave detector including a single-element infrared (IR) photodiode mounted in a cooled Dewar and a preamplifier is developed.\\u000a An IR photodiode of the n\\u000a +-p type is created on the basis of mercury-cadmium telluride (HgCdTe or MCT) heteroepitaxial structures grown by means of molecular\\u000a beam epitaxy. A special profile of MCT structures throughout the MCT layer thickness ensures a

V. V. Vasilyev; S. A. Dvoretsky; V. S. Varavin; N. N. Mikhailov; I. V. Marchishin; Yu. G. Sidorov; A. O. Suslyakov; V. N. Ovsyuk; V. S. Burmasov; S. S. Popov; E. P. Kruglyakov; A. L. Aseev

2007-01-01

68

BGO Readout with Photodiodes as a Soft gamma-Ray Detector at -30C  

SciTech Connect

BGO is expected to be plausible devices for soft gamma-ray detectors, because of a high detection efficiency for soft gamma-rays. Here we report on the good performance of BGO readout with PIN-photodiode or avalanche photodiode as a soft gamma-ray detector. We confirmed that the signal output of BGO becomes comparable to that of GSO when it is readout with photodiodes due to better matching between emission wavelength of BGO and quantum efficiency of photodiode. The energy resolution of 6.2% and 3.4% for 662 keV and 1836 keV, respectively, gamma-rays at -30 C is obtained with the combination of the 5 x 5 x 5 mm{sup 3} cube BGO and the Hamamatsu avalanche photodiode (APD) S8664-55. In this combination, the lowest detectable energy is found to be {approx}10 keV. These performances are better than that obtained with Photomultiplier tube (PMT), and our results increase many possible applications of BGO readout with photodiodes as soft gamma-ray detectors.

Nakamoto, T.

2005-01-21

69

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

70

X-ray detector based on a bulk micromachined photodiode combined with a scintillating crystal  

Microsoft Academic Search

In this paper we report on the design, fabrication, assembly and testing of an x-ray detector based on a bulk micromachined photodiode (BMMPD) with a cavity filled with a scintillating crystal. The x-ray photons that reach the detector are first converted to visible light by the scintillating crystal. The visible light is then detected by the BMMPD, producing an electric

J. G. Rocha; C. G. J. Schabmueller; N. F. Ramos; S. Lanceros-Mendez; M. F. Costa; A. G. R. Evans; R. F. Wolffenbuttel; J. H. Correia

2003-01-01

71

A prototype RICH detector using multi-anode photo multiplier tubes and hybrid photo-diodes  

NASA Astrophysics Data System (ADS)

The performance of a prototype Ring Imaging Cherenkov Detector is studied using a charged particle beam. The detector performance, using CF 4 and air as radiators, is described. Cherenkov angle precision and photoelectron yield using hybrid photo-diodes and multi-anode PMTs agree with simulations and are assessed in terms of the requirements of the LHCb experiment.

Albrecht, E.; Barber, G.; Bibby, J. H.; Brook, N. H.; Doucas, G.; Duane, A.; Easo, S.; Eklund, L.; French, M.; Gibson, V.; Gys, T.; Halley, A. W.; Harnew, N.; John, M.; Piedigrossi, D.; Rademacker, J.; Simmons, B.; Smale, N.; Teixeira-Dias, P.; Toudup, L.; Websdale, D.; Wilkingson, G.; Wotton, S. A.

2001-01-01

72

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

Microsoft Academic Search

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

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

2008-01-01

73

Thin active region, type II superlattice photodiode arrays: Single-pixel and focal plane array characterization  

NASA Astrophysics Data System (ADS)

We have measured the radiometric properties of two midwave infrared photodiode arrays (320×256 pixel2 format) fabricated from the same wafer comprising a thin (0.24 ?m), not intentionally doped InAs/GaSb superlattice between a p-doped GaSb layer and a n-doped InAs layer. One of the arrays was indium bump bonded to a silicon fanout chip to allow for the measurement of properties of individual pixels, and one was bonded to a readout integrated circuit to enable array-scale measurements and infrared imaging. The superlattice layer is thin enough that it is fully depleted at zero bias, and the collection efficiency of photogenerated carriers in the intrinsic region is close to unity. This simplifies the interpretation of photocurrent data as compared with previous measurements made on thick superlattices with complex doping profiles. Superlattice absorption coefficient curves, obtained from measurements of the external quantum efficiency using two different assumptions for optical coupling into the chip, bracket values calculated using an eight-band k.p model. Measurements of the quantum efficiency map of the focal plane array were in good agreement with the single-pixel measurements. Imagery obtained with this focal plane array demonstrates the high uniformity and crystal quality of the type II superlattice material.

Little, J. W.; Svensson, S. P.; Beck, W. A.; Goldberg, A. C.; Kennerly, S. W.; Hongsmatip, T.; Winn, M.; Uppal, P.

2007-02-01

74

Massively Parallel MRI Detector Arrays  

PubMed Central

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

Keil, Boris; Wald, Lawrence L

2013-01-01

75

Uncooled infrared thermal detector arrays  

NASA Astrophysics Data System (ADS)

Uncooled detectors of infra-red radiation exploiting the pyroelectric effect have considerable potential for thermal imaging applications when used in 1-D and 2-D arrays. This paper discusses the factors controlling the performances of such arrays. Lead scandium tantalate is a new ferroelectric ceramic which gives a very high figure-of-merit. The properties of this material are reported and compared and contrasted with those of other ferroelectric ceramics. The possibilites for direct fabrication of thin films of the materials are discussed. Linear arrays of detectors with D-asterisks of up to 5 x 10 to the 8th cmHZ exp 1/2/W and 2-dimensional arrays (up to 100 x 100) with NETDs below 0.2K (25Hz, f/1) have been developed. The technologies for processing these arrays, including the use of reticulation for thermal MTF and microphony improvement, are discussed.

Shorrocks, N. M.; Porter, S. G.; Whatmore, R. W.; Parsons, A. D.; Gooding, J. N.; Pedder, D. J.

1990-10-01

76

New profiled silicon PIN photodiode for scintillation detector  

SciTech Connect

Silicon photodiodes (planar PIN) are employed for the read out of scintillation shower counters. The authors have already reported on a new doping method called molecular layer doping (MLD) which has been developed for very large scale integrated (VLSI) technologies. In tis study, several types of PIN photodiodes, in which a p{sup +} layer was formed by MLD (MLD-PIN) or BFD{sub 2} ion implantation (BF{sub 2} I/I-PIN), have been examined. The MLD-PIN has a shallow P{sup +} junction depth (x{sub j}) with sufficient high surface concentration, and simply and easily provides good performance for a short-wavelength photo sensitivity.

Saitoh, Y.; Akamine, T.; Satoh, K.; Inoue, M.; Yamanaka, J.; Aoki, K.; Miyahara, S.; Kamiya, M.; Ikeda, H.; Avrillon, S.; Okuno, S.

1995-08-01

77

Producibility of Vertically Integrated Photodiode (VIP)tm scanning focal plane arrays  

Microsoft Academic Search

Vertically integrated photodiode, VIPTM, technology is now being used to produce second generation infrared focal plane arrays with high yields and performance. The VIPTM process employs planar, ion implanted, n on p diodes in HgCdTe which is epoxy hybridized directly to the read out integrated circuits on 100 mm Si wafers. The process parameters that are critical for high performance

Arthur M. Turner; Towfik Teherani; John C. Ehmke; Cindy Pettitt; Peggy Conlon; Jeff D. Beck; Kent McCormack; Luigi Colombo; Tom Lahutsky; Terry Murphy; Robert L. Williams

1994-01-01

78

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

79

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

80

BGO suppressed gamma detector arrays  

NASA Astrophysics Data System (ADS)

Arrays of a number of high-resolution ? detectors are needed to investigate the excited states of nuclei in detail, especially in coincidence experiments. The best elements currently available for such arrays use a high-resolution Ge diode detector surrounded by a high-efficiency Bi 4Ge 3O 12 (BGO) scintillator. The BGO scintillator serves to veto those events in which the incoming ?-ray undergoes Compton scattering leading to escape of the scattered photon from the Ge crystal. The first elements of a detector array at the FSU tandem-linac laboratory have been assembled with Ortec high-purity n-type Ge crystals and single crystal BGO scintillators from Harshaw. Each Ge crystal is placed inside a 127 cm diameter by 152 cm long BGO annulus. A smaller 61 mm diameter by 81 mm long BGO split annulus is placed around the cold finger behind the Ge crystal. The performance of the array elements and repair techniques on the Ge detectors are discussed.

Tabor, S. L.

81

Performance of a prototype RICH detector using hybrid photo-diodes  

NASA Astrophysics Data System (ADS)

A prototype Ring-Imaging Cherenkov detector has been operated in a charged particle test beam. Cherenkov photons are imaged onto a plane of hybrid photo-diode detectors. The geometrical arrangement of the prototype and data-taking conditions are described. An analysis of the detector performance, using silica aerogel, air and C 4F 10 gas radiators, is presented. The photon yields and observed Cherenkov angle resolutions are found to be in good agreement with Monte Carlo simulation and satisfy the requirements of the RICH 1 detector in the LHCb experiment.

Albrecht, E.; Barber, G.; Bibby, J. H.; Brook, N. H.; Duane, A.; French, M.; Gibson, V.; Giles, R.; Halley, A. W.; Harnew, N.; John, M.; Miller, D. G.; O'Shea, V.; Teixeira-Dias, P.; Smale, N.; Websdale, D.; Wilkinson, G.; Wotton, S. A.

2001-01-01

82

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

2012-12-01

83

Evaluation of a LiI(Eu) neutron detector with coincident double photodiode readout  

NASA Astrophysics Data System (ADS)

Previous work showed that enriched 6Li halide scintillation crystal is a good candidate for portable neutron-sensitive detectors. Photodiode readout is a good alternative to PMT in compact devices. These detectors are often required to work in presence of a strong gamma background. Therefore, great discrimination against gamma rays is crucial. Because of the high Q-value of the 6Li(n,?) 3H reaction, the light yield of a neutron capture signal corresponds to 3-4 MeV gamma equivalent in spite of the quenching effect of heavily charged particles. As a result, energy discrimination is quite effective against gamma signals generated in thin crystals. However, direct gamma interactions inside the photodiode can create pulses whose amplitude is large enough to interfere with thermal neutron peak. This study shows an innovative design based on coincident readout to solve this problem. In this design, two photodiodes are attached on both sides of the LiI crystal. The output signal is only accepted when both photodiodes give out coincident output. The method is proved to effectively suppress background in the neutron window in a 420 mR/h 137Cs field down to the level of natural background.

Yang, H.; Menaa, N.; Bronson, F.; Kastner, M.; Venkataraman, R.; Mueller, W. F.

2011-10-01

84

Measurement of the spatial characteristics of radiation from pulsed UV lasers by a photodiode array  

Microsoft Academic Search

The MF-14 photodiode array was used to measure the spatial distribution of radiation from pulsed UV lasers. The measured far-field distributions of the radiation from an N2 laser and the far-field distributions of the radiation from XeF, XeCl, and KrF excimer lasers are presented. The angular sizes of the distributions have been measured.

V. M. Gorbachev; V. V. Gorokhov; A. V. Kalutskii; V. I. Karelin; V. N. Korolev; V. I. Smerdov

1992-01-01

85

Determination of the carotenoid content in selected vegetables and fruit by HPLC and photodiode array detection  

Microsoft Academic Search

Epidemiological studies have shown inverse correlations between the consumption of vegetables and fruit rich in carotenoids\\u000a and the incidence of cancer and cardiovascular diseases. A total of 22 species of vegetables (including potatoes) and 28 of\\u000a fruit (including rhubarb) were analysed for their contents of carotenoids by reversed-phase high-performance liquid chromatography\\u000a (RP-HPLC) and photodiode array detection. A total of 27

Harald Müller

1997-01-01

86

Liquid chromatographic–photodiode array mass spectrometric analysis of dietary phytoestrogens from human urine and blood  

Microsoft Academic Search

Dietary phytoestrogens have been implicated in the prevention of chronic diseases. However, it is uncertain whether the phytoestrogens or the foods associated with phytoestrogens account for the observed effects. We report here a new liquid chromatography photodiode array mass spectrometry (LC–PDA-MS) assay for the determination of nanomolar amounts of the most prominent dietary phytoestrogens (genistein, dihydrogenistein, daidzein, dihydrodaidzein, glycitein, O-desmethylangolensin,

Adrian A Franke; Laurie J Custer; Lynne R Wilkens; Abraham M. Y Nomura; Marc T Goodman; Laurence N Kolonel

2002-01-01

87

Coordinated observations of optical lightning from space using the FORTE photodiode detector and CCD imager  

Microsoft Academic Search

This paper presents an overview of the coordinated observation of optical lightning from space using the photodiode detector (PDD) and CCD-based imager known as the Lightning Location System (LLS) aboard the Fast On-Orbit Recording of Transient Events (FORTE) satellite. PDD\\/LLS coincidence statistics are presented and show that both the detected energy density and the detected peak irradiance of optical lightning

D. M. Suszcynsky; T. E. Light; S. Davis; J. L. L. Guillen; W. Myre

2001-01-01

88

Development of neutron detector using the PIN photodiode with polyethylene (n,p) converter  

Microsoft Academic Search

A Si photodiode detector PIN-type 10×10 mm, with a slim film of a converter material capable of producing charged particles, was used as sensor of neutrons and it was projected to be used in an environment of a zero power reactor. Polyethylene n(CH2), which produces recoil protons from the (n,p) interaction, was used to improve the detection efficiency. A mathematical

Carlos H. Mesquita; Tufic Madi Filho; Margarida M. Hamada

2003-01-01

89

Development of neutron detector using the PIN photodiode with polyethylene (n,p) converter  

Microsoft Academic Search

A Si photodiode detector, PIN type, 10×10mm, with a slim film of a converter material, capable to produce charged particles, was used as sensor of neutrons and it was projected to he used in an environment of a zero power reactor. Polyethylene, n(CH2), which produces recoil protons from the (n,p) interaction was used to improve the detection efficiency. The optimal

Carlos H. Mesquita; Tufic Madi Filho; Margarida M. Hamada

2002-01-01

90

A new silicon avalanche photodiode photon counting detector module for astronomy  

Microsoft Academic Search

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

N. S. Nightingale; Cavendish Labomtov

1990-01-01

91

A neutron detector using silicon PIN photodiodes for personal neutron dosimetry  

Microsoft Academic Search

A highly sensitive and small sized neutron detector was devised for use as a personal neutron dosimeter using a silicon PIN photodiode and a gadolinium-foil converter. A detection efficiency of 5.6% was obtained for thermal neutrons by detecting internal-conversion electrons emitted from neutron-captured gadolinium. The gamma-ray component contained in the output pulses was cancelled almost completely by using a twin

Takahiko Aoyama; Yasushi Oka; Kiyonari Honda; Chizuo Mori

1992-01-01

92

Photodiodes selection for the VIRGO detector, the first step.  

National Technical Information Service (NTIS)

In the framework of the Gravitational Waves detector VIRGO, the photodetector system is under construction. The diodes that will be used must satisfy at the same time quite unusual criteria, among them a good quantum efficiency at a wavelength of 1.06 (mu...

B. Caron A. Dominjon R. Flaminio R. Hermel J. C. Lacotte

1994-01-01

93

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

94

Multispectral Linear Array detector technology  

NASA Technical Reports Server (NTRS)

The Multispectral Linear Array (MLA) program sponsored by NASA has the aim to extend space-based remote sensor capabilities. The technology development effort involves the realization of very large, all-solid-state, pushbroom focal planes. The pushbroom, staring focal planes will contain thousands of detectors with the objective to provide two orders of magnitude improvement in detector dwell time compared to present Landsat mechanically scanned systems. Attenton is given to visible and near-infrared sensor development, the shortwave infrared sensor, aspects of filter technology development, the packaging concept, and questions of system performance. First-sample, four-band interference filters have been fabricated successfully, and a hybrid packaging technology is being developed.

Tower, J. R.; Mccarthy, B. M.; Pellon, L. E.; Strong, R. T.; Elabd, H.

1984-01-01

95

Hybrid and monolithic infrared detector arrays  

NASA Astrophysics Data System (ADS)

Infrared detector arrays can be divided in two distinct classes: hybrid (and typically photon) detectors and monolithic (and generally thermal) detectors. Hybrid detectors involve flip-chip integration of the detector array and the readout chip, require cooling and thus cause substantial system cost. Monolithic detectors do not suffer this system overhead and most notably the microbolometer thermal detectors allow ambient operating temperature. IMEC focuses on III-V (InGaAs, InAs and InAsSb) short-wave and mid-infrared detector arrays for hybrid integration on one side and surface micromachined uncooled polySiGe microbolometer arrays on the other hand. Progress in both types of detector systems is reported.

Van Hoof, Chris A.; Zimmermann, Lars; John, Joachim; De Moor, Piet; Kavadias, Spyros; Gastal, Martin; Nemeth, Stefan; Borghs, Gustaaf; Merken, Patrick

2001-02-01

96

A neutron detector using silicon PIN photodiodes for personal neutron dosimetry  

NASA Astrophysics Data System (ADS)

A highly sensitive and small sized neutron detector was devised for use as a personal neutron dosimeter using a silicon PIN photodiode and a gadolinium-foil converter. A detection efficiency of 5.6% was obtained for thermal neutrons by detecting internal-conversion electrons emitted from neutron-captured gadolinium. The ?-ray component contained in the output pulses was cancelled almost completely by using a twin photodiode with a tin foil instead of the gadolinium-foil converter. A low detection limit for neutron flux density of 3.1 × 10 2 cm -2 s -1 was obtained for thermal to 10 keV neutrons with a measurement time of 3 s under ?-ray background with a dose rate of 25 ?Sv/h.

Aoyama, Takahiko; Oka, Yasushi; Honda, Kiyonari; Mori, Chizuo

1992-05-01

97

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

98

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

99

Arrays of Bolometric Detectors for Submillimeter Astronomy  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

100

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

101

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

NASA Technical Reports Server (NTRS)

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

Kenimer, R. L.

1988-01-01

102

Identification and determination of flavonoids in buckwheat (Fagopyrum esculentum Moench, Polygonaceae) by high-performance liquid chromatography with electrospray ionisation mass spectrometry and photodiode array ultraviolet detection.  

PubMed

An analytical method for flavonoids present in the seed extract of buckwheat (Fagopyrum esculentum Moench, Polygonaceae), using HPLC and a photodiode array detector and interfaced to an electrospray ionisation mass spectrometer, has been developed. Structural information about the flavonols was obtained from the retention time characteristics, the UV-visible spectra and the mass spectra without the need to isolate the individual compounds. The methanol extract of buckwheat contained principally four flavonol glycosides: rutin, quercetin, kaempferol-3-rutinoside and a trace quantity of a flavonol triglycoside. PMID:12918868

Tian, Qingguo; Li, Dan; Patil, Bhimanagouda S

2002-01-01

103

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

NASA Technical Reports Server (NTRS)

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

Odenthal, J. P.

1980-01-01

104

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

105

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

106

Large Format Detector Arrays for Astrophysics  

NASA Technical Reports Server (NTRS)

Improvements in detector design and advances in fabrication techniques has resulted in devices which can reach fundamental sensitivity limits in many cases. Many pressing astrophysical questions require large arrays of such sensitive detectors. I will describe the state of far infrared through millimeter detector development at NASA/GSFC, the design and production of large format arrays, and the initial deployment of these powerful new tools.

Moseley, Harvey

2006-01-01

107

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

DOEpatents

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

Strauss, Charlie E. (Santa Fe, NM)

1997-01-01

108

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

DOEpatents

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

Strauss, C.E.

1997-11-18

109

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

110

Investigation of Avalanche Photodiodes and Multipixel Photon Counters as Light Detectors for Cosmic Rays  

NASA Astrophysics Data System (ADS)

Through the Research Scholars Institute, students of Hartnell Community College experimented with the application of avalanche photodiodes (APDs) as cosmic ray detectors during the summer of 2012. An APD detector was coupled with a 10 meter long wavelength shifting fiber (WSF) wrapped around a cylindrical plastic scintillator to maximize signal detection. A photomultiplier tube (PMT) was used in conjunction to detect the same scintillation light caused by incoming cosmic rays. Two APD detectors were evaluated to confirm the viability of the setup. In addition, a similar setup was recently utilized to implement multi-pixel photon counters (MPPCs) as readout detectors. Under this configuration, a high gain preamplifier was used to amplify the signals for both the MPPC and APD detectors. We report on our results characterizing the MPPC and discuss its overall performance. Compared to the APD, our findings suggest that the MPPC detector has greater sensitivity in detecting weak light signals, and can be used in place of the PMT for certain counting applications.

Vasquez, Jaime; Saavedra, Arthur; Ramos, Roxana; Tavares, Pablo; Wade, Marcus; Fan, Sewan; Haag, Brooke

2013-04-01

111

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

112

Signatures of differential Log -V characteristics for non-uniformity analysis of HgCdTe infrared photodiode arrays  

NASA Astrophysics Data System (ADS)

In continuation to our research on the non-uniformity in infrared focal plane arrays of HgCdTe photodiodes, we have examined and found a few important signature parameters in the forward bias region of the electrical characteristics of the photodiodes. These signatures are the peaks of the first and second order derivatives of dynamic resistance-voltage characteristics. They show good correlation with the material and devices parameters and have been investigated to be good signatures for statistical performance variation analysis. In this note, by using theoretical model and statistical analysis of these signatures, we show that the variations in the proposed signatures represent underlying non-uniformity in important material/device parameters. Such signatures may be used along with the other conventional signatures of reverse biased photodiode characteristics to identify the root cause of response non-uniformity in the array with high confidence level.

Saxena, Raghvendra Sahai; Saxena, Aparna

2014-07-01

113

Synchronous Photodiode-Signal Sampler  

NASA Technical Reports Server (NTRS)

Synchronous sampling circuit increases signal-to-noise ratio of measurements of chopped signal of known phase and frequency in presence of low-frequency or dc background noise. Used with linear array of photoelectric sensors for locating edge of metal plate. Multiplexing circuit cycles through 16 light-emitting-diode/photodiode pairs, under computer control. Synchronized with multiplexer so edge detector makes one background-subtracted signal measurement per emitter/detector pair in turn.

Primus, Howard K.

1988-01-01

114

High-speed bridge circuit for InGaAs avalanche photodiode single-photon detector  

NASA Astrophysics Data System (ADS)

Because of low power consumption and small footprint, avalanche photodiodes (APD) have been commonly applied to photon detection. Recently, high speed quantum communication has been demonstrated for high bit-rate quantum key distribution. For the high speed quantum communication, photon detectors should operate at GHz-clock frequencies. We propose balanced detection circuits for GHz-clock operation of InGaAs-APD photon detectors. The balanced single photon detector operates with sinusoidal wave gating. The sinusoidal wave appearing in the output is removed by the subtraction from APD signal without sharp band-elimination filters. Omission of the sharp filters removes the constraint on the operating frequency of the single photon detector. We present two designs, one works with two identical APDs, the other with one APD and a low-pass filter. The sinusoidal gating enables to eliminate the gating noise even with the simple configuration of the latter design. We demonstrated the balanced single photon detector operating with 1.020GHz clock at 233 K, 193 K, and 186.5 K. The dark count probability was 4.0 x 10-4 counts/pulse with the quantum efficiency of 10% at 233K, and 1.6 x 10-4 counts/pulse at 186.5 K. These results were obtained with easily available APDs (NR8300FP-C.C, RENESASS) originally developed for optical time-domain reflectmeters.

Hashimoto, Hirofumi; Tomita, Akihisa; Okamoto, Atsushi

2014-02-01

115

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

116

Profiling and Quantitation of Bacterial Carotenoids by Liquid Chromatography and Photodiode Array Detection  

PubMed Central

An analytical method for the profiling and quantitative determination of carotenoids in bacteria is described. Exhaustive extraction of the pigments from four selected bacterial strains required treatment of the cells with potassium hydroxide or liquefied phenol or both before the addition of the extracting solvent (methanol or diethyl ether). The carotenoids in the extracts were separated by nonaqueous reversed-phase liquid chromatography in conjunction with photodiode array absorption detection. The identity of a peak was considered definitive only when both its retention time and absorption spectrum, before and after chemical reactions, matched those of a reference component. In the absence of the latter, most peaks could be tentatively identified. Two examples illustrate how in the analysis of pigmented bacteria errors may result from using nonchromatographic procedures or liquid chromatographic methods lacking sufficient criteria for peak identification. Carotenoids of interest were determined quantitatively when the authentic reference substance was available or, alternatively, were determined semiquantitatively.

Nelis, H. J.; De Leenheer, A. P.

1989-01-01

117

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

1998-06-01

118

Low-Timing-Jitter Near-Infrared Single-Photon-Sensitive 16-Channel Intensified-Photodiode Detector  

NASA Technical Reports Server (NTRS)

We developed a 16-channel InGaAsP photocathode intensified-photodiode (IPD) detector with 78 ps (1-sigma) timing-jitter, less than 500 ps FWHM impulse response, greater than 15% quantum efficiency at 1064 nm wavelength with 131 kcps dark counts at 15 C.

Krainak, Michael A.; Lu, Wei; Yang, Guangning; Sun, Xiaoli; Sykora, Derek; Jurkovic, Mike; Aebi, Verle; Costello, Ken; Burns, Richard

2011-01-01

119

Pulse-height measurements with a cooled avalanche-photodiode detector.  

PubMed

A cooled avalanche-photodiode (APD) detector has been developed for X-ray diffraction experiments. Although an APD is normally used at room temperature and a high internal gain, the energy resolution can be improved by decreasing temperature and gain. The APD device was cooled to 253 K by a thermoelectric cooler. When the gain was M = 13, the energy resolution was 5% (FWHM) at 16.53 keV with a charge-sensitive preamplifier. By scanning the discriminator threshold level of a fast-counting system, energy spectra were obtained at M approximately 50 and count rates of up to 4.7 x 10(7) s(-1). PMID:15263685

Kishimoto, S

1998-05-01

120

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

2012-02-01

121

Modeling Charge Collection in Detector Arrays  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

122

Self-guarding Schottky barrier infrared detector array  

NASA Astrophysics Data System (ADS)

A two dimensional focal plane array of Schottky photodiodes on a silicon substrate for infrared imaging is presented. The array is designed for mating with multiplexing circuitry and has a self-guarding feature wherein adjacent Schottky electrodes act as guard electrodes. This feature allows a substantial increase of the focal plane area coverage ratio.

Shepherd, F. D., Jr.; Pellegrini, P. W.; Ludington, C. E.; Weeks, M. M.

1985-07-01

123

Simultaneous determination of seven lignans in Justicia procumbens by high performance liquid chromatography-photodiode array detection using relative response factors.  

PubMed

A simple and sensitive HPLC coupled with photodiode array (HPLC-PDA) method was developed for simultaneous determination of seven lignans in Justicia procumbens using relative response factors (RRFs). The chromatographic separation was performed on a Shiseido Capcell Pak C(18) column (250 × 4.6 mm id, 5 ?m), a gradient elution of acetonitrile/water, and a photodiode array detector. The column temperature was maintained at 35°C and the detection wavelength was set at 256 nm. Chinensinaphthol methyl ether was selected as the reference compound for calculating the relative response factors of the lignans. It has shown that the RRFs for lignans are quite similar at 256 nm of detection under different analytical conditions (different columns and HPLC instruments). Using RRFs, not every lignan is needed as a reference standard, making the method ideal for rapid, routine analysis, especially for those laboratories where lignans standards are not readily available. An economic and practicable HPLC method using RRFs was established for the determination of seven lignans in J. procumbens. This method not only can determine multiple indexes in traditional Chinese medicines (TCMs) simultaneously, but also resolve the problem of lacking of chemical standards. It will be a good quality evaluation method and pattern for TCMs. PMID:23355351

Luo, Zuliang; Kong, Weijun; Qiu, Feng; Yang, Meihua; Li, Qian; Wei, Riwei; Yang, Xiaoli; Qin, Jieping

2013-02-01

124

Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector  

NASA Technical Reports Server (NTRS)

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

Huntington, Andrew

2013-01-01

125

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

126

Identification and Determination of Geniposide, Genipin, Gardenoside, and Geniposidic Acid from Herbs by HPLC\\/Photodiode-Array Detection  

Microsoft Academic Search

An improved high-performance liquid chromatographic technique with photodiode-array detection was developed for the identification and determination of the active components geniposide, genipin, gardenoside and geniposidic acid from Gardenia jasminoides Ellis and Gardenia jasminoides Ellis var. grandiflora Nakai. An isocratic system consisting of a reverse-phase phenyl column with a mobile phase of acetonitrile-water-perchloric acid (6:94:0.1. v\\/v\\/v, pH 4.0) was used to

T.-H. Tsm; J. Westly; T.-F. Lee; C.-F. Chen

1994-01-01

127

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

128

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

PubMed

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 70 min using a Waters Symmetry Shield RP 18 column with gradient elution using (A) acetonitrile, (B) water, and (C) acetic acid at a flow rate of 1 ml/min, and with a PDA detector. All calibration curves showed good linear regression (r(2)>0.9992) within the test ranges. The method was validated for specificity, accuracy, precision, and limits of detection. The proposed method enables in a single run the simultaneous identification and determination for quality control of 12 multi-structural components of XYSJW forming the basis of its therapeutic effect. PMID:18977108

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

2008-12-15

129

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

130

Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors  

NASA Astrophysics Data System (ADS)

My dissertation is comprised of three projects: 1) studies of Lyman-alpha Emitting galaxies (LAEs), 2) radiation hardness studies of InGaAs photodiodes (PDs), and 3) scintillation photon detection in liquid argon (LAr) neutrino detectors. I began work on the project that has now become WFIRST, developing a science case that would use WFIRST after launch for the observation of LAEs. The radiation hardness of PDs was as an effort to support the WFIRST calibration team. When WFIRST was significantly delayed, I joined an R&D effort that applied my skills to work on photon detection in LAr neutrino detectors. I report results on a broadband selection method developed to detect high equivalent width (EW) LAEs. Using photometry from the CFHT-Legacy Survey Deep 2 and 3 fields, I have spectroscopically confirmed 63 z=2.5-3.5 LAEs using the WIYN/Hydra spectrograph. Using UV continuum-fitting techniques I computed properties such as EWs, internal reddening and star formation rates. 62 of my LAEs show evidence to be normal dust-free LAEs. Second, I present an investigation into the effects of ionizing proton radiation on commercial off-the-shelf InGaAs PDs. I developed a monochromator-based test apparatus that utilized NIST-calibrated reference PDs. I tested the PDs for changes to their dark current, relative responsivity as a function of wavelength, and absolute responsivity. I irradiated the test PDs using 30, 52, and 98 MeV protons at the IU Cyclotron Facility. I found the InGaAs PDs showed increased dark current as the fluence increased with no evidence of broadband response degradation at the fluences expected at an L2 orbit and a 10-year mission lifetime. Finally, I detail my efforts on technology development of both optical detector technologies and waveshifting light guide construction for LAr vacuum UV scintillation light. Cryogenic neutrino detectors use photon detection for both accelerator based science and for SNe neutrino detection and proton decay. I have developed waveshifter doped cast acrylic light guides that convert scintillation light and guide the waveshifted light to SiPMs detectors.

Baptista, Brian

131

Toward very large format infrared detector arrays  

NASA Astrophysics Data System (ADS)

Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024x1024 pixel InGaAs/GaAs/AlGaAs based quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NE?T) of 17 mK at a 95K operating temperature with f/2.5 optics at 300K background and the LWIR detector array has demonstrated a NE?T of 13 mK at a 70K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90K and 70K operating temperatures respectively, with similar optical and background conditions. It is well known that III-V compound semiconductor materials such as GaAs, InP, etc. are easy to grow and process into devices. In addition, III-V compound semiconductors are available in large diameter wafers, up to 8-inches. Thus, III-V compound semiconductor based infrared focal plane technologies such as QWIP, InSb, and strain layer superlattices (SLS) are potential candidates for the development of large format focal planes such as 4096x4096 pixels and larger. In this paper, we will discuss the possibility of extending the infrared detector array size up to 16 megapixels.

Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Hill, C. J.; Ting, D. Z.; Kurth, E.; Woolaway, J.; LeVan, P. D.; Tidrow, M. Z.

2007-12-01

132

Schottky type photodiodes as detectors in the VUV and soft x-ray range.  

PubMed

The quantum efficiencies of semiconductor photodiodes have been measured at photon energies from 5 to 3500 eV. For silicon photodiodes strong radiation-induced effects were found. GaAsP and GaP Schottky diodes show remarkable stability and high quantum efficiency. Use of Schottky diodes for spectroscopic and radiometric measurements is discussed. PMID:20539564

Krumrey, M; Tegeler, E; Barth, J; Krisch, M; Schäfers, F; Wolf, R

1988-10-15

133

EUV detectors based on AlGaN-on-Si Schottky photodiodes  

NASA Astrophysics Data System (ADS)

Photodetectors designed for the Extreme Ultraviolet (EUV) range with the Aluminum Gallium Nitride (AlGaN) active layer are reported. AlGaN layers were grown by Molecular Beam Epitaxy (MBE) on Si(111) wafers. Different device structures were designed and fabricated, including single pixel detectors and 2D detector arrays. Sensitivity in different configurations was demonstrated, including front- and backside illumination. The latter was possible after integration of the detector chips with dedicated Si-based readouts using high-density In bump arrays and flip-chip bonding. In order to avoid radiation absorption in silicon, the substrate was removed, leaving a submicron-thin membrane of AlGaN active layer suspended on top of an array of In bumps. Optoelectrical characterization was performed using different UV light sources, also in the synchrotron beamlines providing radiation down to the EUV range. The measured cut-off wavelength of the active layer used was 280 nm, with a rejection ratio of the visible radiation above 3 orders of magnitude. Spectral responsivity and quantum efficiency values

Malinowski, P. E.; Duboz, J.-Y.; de Moor, P.; Minoglou, K.; John, J.; Srivastava, P.; Semond, F.; Frayssinet, E.; Benmoussa, A.; Giordanengo, B.; van Hoof, C.; Mertens, R.

2011-05-01

134

SPAD Array Detectors for Astrophysical Applications.  

NASA Astrophysics Data System (ADS)

Astrophysical studies require more and more accurate, sensitive and fast detectors to detect faint sources with high variability. Since the ST-Microelectronics of Catania has been working on the development silicon devices and monolithic arrays called "SPAD" (Single Photon Avalanche Diode). These detectors are very innovative and have caracteristics that will offer interesting opportunities in astrophysics and in other science field. We describe the state of the art of the devices, the present limitations, the solutions and the potentialities of these arrays in adaptive optics and for the detection in the visible of astrophysical fast transient phenomena. We, moreover, describe the adopted solutions for the mechanical housing, the detection and control electronics, and report on the relevant electro-optical characteristics of these detectors.

Belluso, M.; Mazzillo, M. C.; Bonanno, G.; Billotta, S.; Scuderi, S.; Calí, A.; Micciché, A.; Timpanaro, M. C.; Sanfilippo, D.; Fallica, P. G.; Sciacca, E.; Lombardo, S.; Morabito, A.

135

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

136

An experimental photodiode array unit for ultrahigh-resolution recording of X-ray images  

NASA Astrophysics Data System (ADS)

The geometrical resolution of modern solid-state X-ray imagers (photodiode arrays, PDA, and charge-coupled devices, CCD) is defined by their sensitive-pixel sizes and ranges from 10 up to 20 ?m, i.e. these imagers yield considerably to photoemulsions in the resolution (0.1-1 ?m of emulsions). In the present paper, an attempt to create a recording unit with a spatial resolution comparable to that of photoemulsions is described. First results of testing of the unit is described. The last was fabricated on the basis of a PDA containing 1024 sensitive pixels which are 150 ?m high and are positioned with a 25 ?m step. The feature of the given PDA consists of the presence of an individual charge-sensitive amplifier in each pixel. This allowed us to realize an algorithm of the digital double correlated sampling and to remove KTC noise which, under ordinary conditions, limits the PDA sensitivity. To diminish the noise level, the unit is provided with a double-correlated-sampling analog highway, which removes {1}/{f} noises of the on-chip read preamplifiers and possesses the LF filter qualities, and with cooling of the PDA by a two-stage battery of Peltier cells. The unit was tested in the mode of the integrating X-ray imager. It is expected, by corresponding computer processing of the separate X-ray photon absorption events, that one will succeed in determining each event coordinate while allowing for the signal charge distribution between pixels due to charge diffusion in the PDA substratum.

Fedotov, M. G.; Panchenko, V. E.

1995-02-01

137

Development of the ORRUBA Silicon Detector Array  

SciTech Connect

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

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

2009-01-01

138

The quick single-photon detector with many avalanche photo-diodes for quantum key distribution  

NASA Astrophysics Data System (ADS)

It is the closest technology to practice in the quantum communication at present to apply single-photon scheme to implement the quantum key distribution (QKD), and may achieve the absolute security in principle. Because of the limit of the response speed of the present single-photon detector, the code rate is still too low to come into practical use. The paper has put up a new idea to design a quick single-photon detector with a multi-port optic-fiber splitter or an optical switch array and many avalanche photo diodes (APD). All of the ports with APD work on time division and cooperate with the logic discrimination and deciding unit by the clock signal, thus the quick detection can come true to high repetition-rate pulses with a single photon. The multiple of the detection rate is decided by the number of the port. The optoelectronic integration can be adopted for the reliable detector. The applying of this detector will largely raise the code rate of the QKD, and stimulate the commercial use.

Peng, Jian; Yao, Li; Fu, YiFei; Xiang, XuDong; Lu, ZhiXin; Yang, BoJun; Yu, Li

2008-01-01

139

Multiband selection with linear array detectors  

NASA Technical Reports Server (NTRS)

Several techniques that can be used in an earth-imaging system to separate the linear image formed after the collecting optics into the desired spectral band are examined. The advantages and disadvantages of the Multispectral Linear Array (MLA) multiple optics, the MLA adjacent arrays, the imaging spectrometer, and the MLA beam splitter are discussed. The beam-splitter design approach utilizes, in addition to relatively broad spectral region separation, a movable Multiband Selection Device (MSD), placed between the exit ports of the beam splitter and a linear array detector, permitting many bands to be selected. The successful development and test of the MSD is described. The device demonstrated the capacity to provide a wide field of view, visible-to-near IR/short-wave IR and thermal IR capability, and a multiplicity of spectral bands and polarization measuring means, as well as a reasonable size and weight at minimal cost and risk compared to a spectrometer design approach.

Richard, H. L.; Barnes, W. L.

1985-01-01

140

A new single nucleotide polymorphisms typing method and device by bioluminometric assay coupled with a photodiode array  

NASA Astrophysics Data System (ADS)

Easy and inexpensive single nucleotide polymorphisms (SNPs) typing systems are required for the practice of genetic testing as well as genetic medicine. Most of the SNPs typing systems use laser-induced fluorescence detection coupled with fluorophore tagging on DNA, which are expensive. A new simple and inexpensive SNPs typing system is presented. It uses a bioluminometric assay coupled with modified primer extension reactions and an inexpensive photodiode array for the luminometric detection. The reagents consumed in the assay are also inexpensive. Although the system is very small, simple and inexpensive, it gives enough sensitivity for detecting target DNAs as small as 10 fmol, which is good enough for SNPs typing.

Kamahori, Masao; Harada, Kunio; Kambara, Hideki

2002-11-01

141

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

142

Multi-channel photon counting three-dimensional imaging laser radar system using fiber array coupled Geiger-mode avalanche photodiode  

NASA Astrophysics Data System (ADS)

Photon counting laser radar is the most sensitive and efficiency detection method of direct-detection laser radar. With the use of Geiger-mode avalanche photodiode (APD) or other single photon detectors, every laser photon could be sufficiently used for ranging and three-dimensional imaging. The average energy of received laser signal could be as low as a single photon, or even less than one. This feature of photon counting laser radar enables ranging under conditions of long range, low laser pulse energy, and multi-pixel detection, while receiver size, mass, power, and complexity of laser radar are reduced. In this paper, a latest multi-channel photon counting 3D imaging laser radar system using fiber array coupled Geiger-mode avalanche photodiode (APD) is introduced. Detection model based on Poisson statistics of a photon counting laser radar is discussed. A laser radar system, working under daylight condition with ultra-low signal level (less than single photon per pulse), has been designed and analyzed with the detection model and photon counting three-dimensional imaging theory. A passively Q-switched microchip laser is used to transmit short sub-nanosecond laser pulses at 532nm. The output laser is divided into 1×8 laser spots, which correspond to 8 Geiger-mode avalanche photodiodes coupled by a 1×8-pixel fiber array. A FPGA based time-to-digital converter (TDC), which is designed by delay line interpolation technology, is used for multi-hit signal acquisition. The algorithm of photon counting three-dimensional imaging is developed for signal photon events extraction and noise filter. Three-dimensional images under daylight conditions were acquired and analyzed. The results show that system could operate at strong solar background. The ranging accuracy of the system is 6.3cm (?) while received laser pulse signal level is only 0.04 photoelectrons on average. The advantages and feasibility of photon counting laser radar working at daylight have been demonstrated experimentally.

Shu, Rong; Huang, Genghua; Hou, Libing; He, Zhiping; Hu, Yihua

2012-09-01

143

InP-based Geiger-mode avalanche photodiode arrays for three-dimensional imaging at 1.06 ?m  

NASA Astrophysics Data System (ADS)

We report on the development of 32 x 32 focal plane arrays (FPAs) based on InGaAsP/InP Geiger-mode avalanche photodiodes (GmAPDs) designed for use in three-dimensional (3-D) laser radar imaging systems at 1064 nm. To our knowledge, this is the first realization of FPAs for 3-D imaging that employ a planar-passivated buried-junction InP-based GmAPD device platform. This development also included the design and fabrication of custom readout integrate circuits (ROICs) to perform avalanche detection and time-of-flight measurements on a per-pixel basis. We demonstrate photodiode arrays (PDAs) with a very narrow breakdown voltage distribution width of 0.34 V, corresponding to a breakdown voltage total variation of less than +/- 0.2%. At an excess bias voltage of 3.3 V, which provides 40% pixel-level single photon detection efficiency, we achieve average dark count rates of 2 kHz at an operating temperature of 248 K. We present the characterization of optical crosstalk induced by hot carrier luminescence during avalanche events, where we show that the worst-case crosstalk probability per pixel, which occurs for nearest neighbors, has a value of less than 1.6% and exhibits anisotropy due to isolation trench etch geometry. To demonstrate the FPA response to optical density variations, we show a simple image of a broadened optical beam.

Itzler, Mark A.; Entwistle, Mark; Owens, Mark; Jiang, Xudong; Patel, Ketan; Slomkowski, Krystyna; Koch, Tim; Rangwala, Sabbir; Zalud, Peter F.; Yu, Young; Tower, John; Ferraro, Joseph

2009-05-01

144

Multianode microchannel array detectors for Space Shuttle imaging applications  

Microsoft Academic Search

The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric, photoncounting array detectors that have been developed and qualified specifically for use in space. MAMA detectors with formats as large as 256 x 1024 pixels are now in use or under construction for a variety of imaging and tracking applications. These photo-emissive detectors can be operated in a windowless configuration

J. G. Timothy; R. L. Bybee

1981-01-01

145

Impact of a New Highly Sensitive HgCdTe Avalanche Photodiode Detector on Receiver Performance for the CO2 Sounder Lidar for the ASCENDS Mission  

NASA Astrophysics Data System (ADS)

NASA Goddard Space Flight Center (GSFC) is currently developing a CO2 lidar as a candidate for the NASA's planned ASCENDS mission under the support of Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP). As part of this work we have demonstrated new type of lower noise HgCdTe avalanche photodiode (APD) multi-element detector for the lidar receiver. This significantly improves the receiver sensitivity, lower the laser power, and reduce the receiver telescope size compared to InGaAs photomultiplier tubes (PMT) and APDs currently used. The HgCdTe APD arrays were designed and manufactured by DRS Technologies, Reconnaissance, Surveillance and Target Acquisition (RSTA) Division, which combines their mature HgCdTe APD detector in a hybrid package with a new custom cryogenic silicon preamplifier. The new detectors were specially designed for our airborne CO2 lidar and operate at ~ 77K inside a turn-key closed-cycle cooler. The detector has 80 ?m square pixels in a 4x4 array, and >70% fill factor and was custom designed to match the optics of our airborne and eventually space-based CO2 lidar. The initial results of evaluating the detector at NASA GSFC showed the HgCdTe APD assembly has a quantum efficiency of ~90% near 1550-nm, >500 APD gain, 8-10 MHz electrical bandwidth, and an average noise equivalent power of <1fW/Hz1/2. The detector also has a much wider linear dynamic range than PMTs, since it operates in a linear analog mode and has variable gain. Given the wide range of surface reflectivities this is important for ASCENDS. The new detector also greatly improves our CO2 lidar's receiver sensitivity. Calculations show it enables us to reduce the laser transmitter power by half for the space borne instrument while staying with a conventional reasonably sized (~1.2 m) diameter receiver telescope. We will show analysis and laboratory test results of the CO2 lidar performance using a receiver with this new detector. We are also funded by NASA ESTO to develop a high bandwidth HgCdTe APD under an Advanced Component Technology (ACT) program. DRS RSTA will use a new higher speed preamplifier and reduce the input capacitance to further reduce the noise and achieve linear mode photon counting performance.

Sun, X.; Abshire, J. B.

2013-12-01

146

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

147

Neutron Holography Measurement Using Multi Array Detector  

NASA Astrophysics Data System (ADS)

Atomic-resolution neutron holography was carried out utilizing the powder diffrcatometer in JRR-3M reactor. Spherically emitted neutrons around a PdH0.78 single crystal produced by incoherent neutron-proton scattering, which formed a hologram, were efficiently collected using multi array 3He detectors. In addition to the hologram data, strong undulation due to the elastic thermal scattering was observed. To exclude this effect, the thermal scattering pattern was calculated and subtracted from the measured data. From the resulting hologram data, neighboring Pd and H nuclei images were successfully reconstructed.

Hayashi, Kouichi; Ohoyama, Kenji; Orimo, Shin-ichi; Nakamori, Yuko; Takahashi, Hideyuki; Shibata, Kaoru

2008-04-01

148

Astronomical imaging with infrared array detectors.  

PubMed

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

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

1988-12-01

149

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.

150

CsI(Tl) detector in a close-packed array  

SciTech Connect

The entrance window on the front face of the crystal is made of 0.7 {mu}m aluminum leaf purchased from a local art store. This material is thinner and easier to handle than thin aluminized Mylar. The sides of the 6 cm long CsI(TI) crystal are coated with a diffuse reflecting material made by suspending commercial TiO{sub 2} paint pigment (a fine white power) in a low viscosity, two part epoxy, EPO-TEK 301-2{sup {trademark}} A layer, tens of {mu}m thick, is trowled onto the surface of the crystal and allowed to cure. Aluminum leaf is used between the white layers of adjacent crystals to eliminate cross talk. To fit into the 60 detector array, the crystals have a trapezoidal cross section (a few cm{sup 2} in area). The best resolution is achieved when the light-collecting photodiode fully covers the end of the CsL Custom photodiodes from Silicon Sensors, Inc., Dodgeville, WI, match the shapes of the closely packed CsI crystals. These photodiodes have guard rings, but no frames around the edge of the silicon.

Yang, L.B.; Norbeck, E.; Pogodin, P. [and others

1995-10-01

151

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

152

Contactless conductivity detector array for capillary electrophoresis.  

PubMed

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

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

2014-02-01

153

Digital radiography: Present detectors and future developments  

SciTech Connect

Present detectors for digital radiography are of two classes: real time detectors and storage (non real time) types. Present real time detectors consist of image intensifier tubes with an internal cesium iodide layer x-ray converter. Non real time detectors involve linear sweep arrays or storage detectors such as film. Future detectors discussed here can be of both types utilizing new technologies such as hydrogenated amorphous silicon photodiode arrays coupled to thin film transistor arrays. 17 refs., 10 figs.

Perez-Mendez, V.

1990-08-01

154

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

PubMed

Silicon photomultipliers (SiPMs) are of great interest to positron emission tomography (PET), as they enable new detector geometries, for e.g., depth-of-interaction (DOI) determination, are MR compatible, and offer faster response and higher gain than other solid-state photosensors such as avalanche photodiodes. Here we present a novel detector design with DOI correction, in which a position-sensitive SiPM array is used to read out a monolithic scintillator. Initial characterization of a prototype detector consisting of a 4 x 4 SiPM array coupled to either the front or back surface of a 13.2 mm x 13.2 mm x 10 mm LYSO:Ce(3+) crystal shows that front-side readout results in significantly better performance than conventional back-side readout. Spatial resolutions <1.6 mm full-width-at-half-maximum (FWHM) were measured at the detector centre in response to an approximately 0.54 mm FWHM diameter test beam. Hardly any resolution losses were observed at angles of incidence up to 45 degrees , demonstrating excellent DOI correction. About 14% FWHM energy resolution was obtained. The timing resolution, measured in coincidence with a BaF(2) detector, equals 960 ps FWHM. PMID:19443953

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

2009-06-01

155

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

156

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

Microsoft Academic Search

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

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

1998-01-01

157

Development of a quantitative high-performance liquid chromatography-photodiode array detection measurement system for phenolic acids.  

PubMed

A quantitative high-performance liquid chromatography-photodiode array detection method separating 16 phenolic acids was achieved. Six columns and several mobile phases were investigated. Resolution was achieved with a high-purity silica Phenomenex Luna C18 column (150 mm x 4.6 mm, 5 microm) and a binary gradient consisting of CH3OH-water (with 0.1% formic acid) and flow rate set at 0.7 ml/min. Acids were detected and quantitation performed at wavelength representing the lowest energy lambda(max) for individual acids. Extraction procedure from wine was optimized and yields ranged from 79 to 87% based on internal standard recovery. To confirm our quantitative results, identical samples were analyzed both in-house and by a collaborating laboratory. Correlation of two data sets generated linear regression equations that approached unity (0.93-0.98) and R2 values ranging from 0.990 to 0.999. PMID:15233525

Robbins, Rebecca J; Bean, Scott R

2004-06-01

158

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

PubMed

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

Matos Pires, Nuno Miguel; Dong, Tao

2013-01-01

159

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

PubMed Central

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

Pires, Nuno Miguel Matos; Dong, Tao

2013-01-01

160

Multiwavelength infrared focal plane array detector  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

161

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

162

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

163

Detector arrays for low-background space infrared astronomy  

Microsoft Academic Search

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

C. R. McCreight; M. E. McKelvey; J. H. Goebel; G. M. Anderson; J. H. Lee

1986-01-01

164

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

SciTech Connect

We present construction methods and performance results for a production scintillator array of 64 optically isolated, 3 mm x 3 mm x 30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8x8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PD). The PMT provides an accurate timing pulse and initial energy discrimination, the PD identifies the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction (DOI). Unlike the previous LSO array prototypes, we now glue Lumirror reflector material directly onto 4 sides of each crystal to obtain an easily manufactured, mechanically rugged array with our desired depth dependence. With 511 keV excitation, we obtain a total energy signal of 3600 electrons, pulse-height resolution of 25% fwhm, and 6-15 mm fwhm DOI resolution.

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

2000-10-30

165

Fabrication of Pop-up Detector Arrays on Si Wafers  

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

166

A validated high performance liquid chromatograph-photodiode array method for simultaneous determination of 10 bioactive components in compound hongdoushan capsule  

PubMed Central

Background: The compound Hongdoushan capsule (CHC) is widely known as compound herbal preparation and is often used to treat ovarian cancer and breast cancer, and to enhance the body immunity, etc., in clinical practice. Objective: To determine simultaneously 10 bioactive components from CHC, namely glycyrrhetinic acid, liquiritin, glycyrrhizin, baccatin III, 10-deacetylbaccatin III, cephalomannine, taxol, ginsenoside Rg1, ginsenoside Re, and ginsenoside Rb1. Materials and Methods: A high performance liquid chromatograph method coupled with photodiode array detector was developed and validated for the 1st time. Chromatographic analysis was performed on a SHIMADZU C18 by utilizing a gradient elution program. The mobile phase was acetonitrile (A)-water (B) at a flow rate of 0.8 mL/min. Results: The calibration curve was linear over the investigated concentration ranges with the values of r2 higher than 0.9993 for all the 10 bioactive components. The average recovery rates range from 98.4% to 100.5% with relative standard deviations ?2.9%. The developed method was successfully applied to analyze 10 compounds in six CHC samples from different batches. In addition, the herbal sources of 32 chromatographic peaks were identified through comparative studying on chromatograms of standard, the respective extracts of Hongdoushan, RenShen, GanCao, and CHC. Conclusion: All the results imply that the accurate and reproducible method developed has high separation rate and enables the determination of 10 bioactive components in a single run for the quality control of CHC.

Zhu, Liancai; Yang, Xian; Tan, Jun; Wang, Bochu; Zhang, Xue

2014-01-01

167

Speciation of mercury by ionic liquid-based single-drop microextraction combined with high-performance liquid chromatography-photodiode array detection.  

PubMed

Room temperature ionic liquids can be considered as environmentally benign solvents with unique physicochemical properties. Ionic liquids can be used as extractant phases in SDME, being compatible with chromatographic systems. A single-drop microextraction method was developed for separation and preconcentration of mercury species (MeHg(+), EtHg(+), PhHg(+) and Hg(2+)), which relies on the formation of the corresponding dithizonates and microextraction of these neutral chelates onto a microdrop of an ionic liquid. Afterwards, the separation and determination were carried out by high-performance liquid chromatography with a photodiode array detector. Variables affecting the formation and extraction of mercury dithizonates were optimized. The optimum conditions found were: microextraction time, 20 min; stirring rate, 900 rpm; pH, 11; ionic liquid type, 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]); drop volume, 4 microL; and no sodium chloride addition. Limits of detection were between 1.0 and 22.8 microg L(-1) for the four species of mercury, while the repeatability of the method, expressed as relative standard deviation, was between 3.7 and 11.6% (n=8). The method was finally applied to the determination of mercury species in different water samples. PMID:19203620

Pena-Pereira, Francisco; Lavilla, Isela; Bendicho, Carlos; Vidal, Lorena; Canals, Antonio

2009-04-30

168

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

169

Performance characteristics of multi-anode microchannel array detector systems  

NASA Technical Reports Server (NTRS)

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

Timothy, J. G.

1984-01-01

170

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

NASA Technical Reports Server (NTRS)

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

Arbel, D.; Schwartz, J. A.

1991-01-01

171

The 1.06 micrometer avalanche photodiode detectors with integrated circuit preamplifiers  

NASA Technical Reports Server (NTRS)

The development of a complete solid state 1.06 micron optical receiver which can be used in optical communications at data rates approaching 1.5 Gb/s, or in other applications requiring sensitive, short-pulse detection, is reported. This work entailed both the development of a new type of heterojunction 3-5 semiconductor alloy avalanche photodiode and an extremely charge-sensitive wideband low-noise preamp design making use of GaAs Schottky barrier-gate field effect transistors.

Eden, R. C.

1975-01-01

172

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

PubMed Central

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

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

2013-01-01

173

Sub-Terahertz Radiation from a Photodiode-Integrated Patch Antenna Array  

Microsoft Academic Search

Enhancement of sub-terahertz radiation power from photonic emitters in an array scheme is investigated. The element of the fabricated array antenna was a UTC-PD integrated 300-GHz patch antenna. It was observed that the radiation angle of patch antenna array is about half as narrow as that of a single patch antenna. We also confirm that the radiation direction changed by

Naofumi Shimizu; T. Nagatsuma

2005-01-01

174

Multianode microchannel array detectors for Space Shuttle imaging applications  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

175

Gene expression analysis on a photodiode array-based bioluminescence analyzer by using sensitivity-improved SRPP.  

PubMed

Most methods used for gene expression analysis are based on dye-labeling, which requires costly instruments. Recently a dye-free gene expression analysis method-SRPP (Sequence-tagged reverse-transcription polymerase chain reaction coupled with pyrosequencing) was developed to compare relative gene expression levels in different tissues, but the throughput of the SRPP assay is very limited due to the use of a photomultiplier tube (PMT)-based pyrosequencer for the detection. To increase the throughput of the SRPP assay, an inexpensive photodiode (PD) array-based bioluminescence analyzer (termed as "PD-based pyrosequencer") was coupled to SRPP; however the low sensitivity of PD limited the wide application of SRPP. To enable SRPP analyzing low abundance genes in clinical samples, sequence-tagged gene-specific primers instead of sequence-tagged poly (T)(n) primers were used for reverse-transcription, and the SRPP sensitivity was thus improved more than 10 times. This improvement compensates the sensitivity loss due to the use of PD in a pyrosequencer. The accurate determination of the expression levels of ten prognostic marker genes (AL080059, MMP9, EXT1, ORC6L, AF052162, C9orf30, FBXO31, IGFBP5, ESM1, and RUNDC1) differing between normal tissues and tumor tissues of breast cancer patients demonstrated that SRPP using gene-specific RT primers coupled with the PD array-based bioluminescence analyzer is reliable, inexpensive, and sensitive in gene expression analysis. PMID:20498880

Song, Qinxin; Jing, Hua; Wu, Haiping; Zhou, Guohua; Kajiyama, Tomoharu; Kambara, Hideki

2010-06-01

176

Determination of mercury vapor in air using electrically heated, gold-coated wire-loops, in-torch vaporization sample introduction and inductively coupled plasma atomic emission spectrometry with photodiode array detection  

NASA Astrophysics Data System (ADS)

A method for the determination of Hg 0 vapor in ambient air using an electrically heated, Au-coated wire-loop, in-torch vaporization (ITV) sample introduction and inductively coupled plasma atomic emission spectrometry (ICP-AES) spectrometry with photodiode array detection is described. Tungsten wire-loops were coated with gold using sputtering methodology developed for scanning electron microscopy (SEM). Mecury vapor formed an amalgam with Au on the wire-loop, the wire-loop was inserted into a modified ICP torch about 10 cm below the plasma and electrical power was applied to the loop, thus thermally releasing mercury. Atomic emission was monitored using an ICP spectrometer equipped with a photodiode array detector. Calibration curves were constructed using a variation of the reduction-aeration method and were linear for about two-and-a-half orders of magnitude. Mercury vapor levels determined close to a polarography apparatus compared favorably with measurements taken at the same location using cold vapor atomic absorption spectrometry (CVAAS). The possibility of using a Au-coated wire-loop system as an integrating personal dosimeter is postulated.

Karanassios, Vassili; Bateman, Kevin P.; Spiers, Graeme A.

1994-08-01

177

1-D array of perforated diode neutron detectors  

NASA Astrophysics Data System (ADS)

Performance of a 4 cm long 64-pixel perforated diode neutron detector array is compared with an identical array of thin-film coated diodes. The perforated neutron detector design has been adapted to a 1-D pixel array capable of 120 ?m spatial resolution and counting efficiency greater than 12%. Deep vertical trenches filled with 6LiF provide outstanding improvement in efficiency over thin-film coated diode designs limited to only 4.5%. This work marks the final step towards the construction of a much larger array consisting of 1024 pixels spanning 10 cm. The larger detector array will be constructed with a sub-array of 64-pixel sensors, and will be used for small-angle neutron scattering experiments at the Spallation Neutron Source of Oak Ridge National Laboratory.

McNeil, Walter J.; Bellinger, Steven L.; Unruh, Troy C.; Henderson, Chris M.; Ugorowski, Phil; Morris-Lee, Bryce; Taylor, Russell D.; McGregor, Douglas S.

2009-06-01

178

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

179

Si:Bi Switched Photoconductor Infrared Detector Array.  

National Technical Information Service (NTIS)

A multiplexed infrared detector array is described. The small demonstration prototype consisted of two cryogenically cooled, bismuth doped silicon, extrinsic photoconductor pixels multiplexed onto a single output channel using an on focal plane switch int...

C. E. Eakin

1983-01-01

180

Development of 58 x 62 Si:Sb detector arrays  

NASA Technical Reports Server (NTRS)

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

Worley, S.; Gaalema, S.

1986-01-01

181

Developments in large gamma-ray detector arrays  

NASA Astrophysics Data System (ADS)

Gamma-ray spectroscopy was revolutionized with the introduction of high energy-resolution semiconductor germanium (Ge) detectors in the early 1960s. This led to the large increase in sensitivity realized by today's arrays of Compton-suppressed Ge detectors. A still larger increase in sensitivity is expected by implementing the new concept of tracking. A tracking array consists of highly segmented Ge detectors (that can cover the full 4pi solid-angle) in which gamma rays will be identified by measuring and tracking every gamma ray interaction. This article reviews the physics motivation for such detectors and the development of the new technologies involved. The concept of tracking is explained using the example of a proposed array called gamma-ray energy tracking array (GRETA).

Lee, I. Y.; Deleplanque, M. A.; Vetter, K.

2003-07-01

182

PbS-PbSe IR detector arrays  

NASA Technical Reports Server (NTRS)

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

Barrett, John R. (Inventor)

1986-01-01

183

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

184

Simultaneous determination of vitamins C, E and ?-carotene in human plasma by high-performance liquid chromatography with photodiode-array detection  

Microsoft Academic Search

Purpose: To develop a high-performance liq- uid chromatography (HPLC) method with photodiode- array ultraviolet detection for the simultaneous determi- nation of vitamin C, vitamin E and ?-carotene. Meth- ods: Following liquid-phase extraction from the human plasma samples, these three vitamins were successfully separated on the LiChrospher 100 RP-18 column (125 × 4 mm I.D.; particle size, 5 µm) at a

Bin Zhao; Su-Yin Tham; Jia Lu; Mui Hoon Lai; Lionel K. H. Lee; Shabbir M Moochhala

185

Application of liquid chromatography with mass spectrometry combined with photodiode array detection and tandem mass spectrometry for monitoring pesticides in surface waters  

Microsoft Academic Search

Liquid chromatography with photodiode array detection (LC–DAD) and liquid chromatography with mass spectrometry (LC–MS) are two techniques that have been widely used in monitoring pesticides and their degradation products in the environment. However, the application of liquid chromatography with tandem mass spectrometry (LC–MS–MS) for such purposes, once considered too costly, is now gaining considerable ground. In this study, we compare

Roger Jeannot; Hassan Sabik; Emmanuel Sauvard; Eric Genin

2000-01-01

186

Design of a large-area CsI(Tl) photo-diode array for explosives detection by neutron-activation gamma-ray spectroscopy  

Microsoft Academic Search

A design for a large area, position-sensitive gamma-ray spectrometer for use in imaging explosive materials is described. The design has been optimised for use in the energy range from 2 to 12MeV. At 5MeV, the spectral resolution of each CsI(Tl)-photodiode pixel is better than 3% FWHM. The multi-element detector system, when used in conjunction with a coded-aperture mask, is able

R. J Evans; I. D Jupp; F Lei; D Ramsden

1999-01-01

187

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

188

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

189

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

PubMed

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

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

2014-01-01

190

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

191

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

192

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

193

64-Pixel linear-array Si-APD detector for X-ray time-resolved experiments  

NASA Astrophysics Data System (ADS)

We have developed a silicon avalanche-photodiode (Si-APD) linear array detector to be used for time-resolved measurements in pulsed synchrotron X-ray experiments. The Si-APD linear array consists of 64 pixels 100×200 ?m2, with a pixel pitch of 150 ?m and a depletion depth of 10 ?m. The nanosecond response and high counting rate of the Si-APD are very valuable for time-resolved X-ray diffraction experiments using pulsed synchrotron radiation. A detector system that can resolve successive X-ray pulses within a short interval of 2 ns would be very efficient for recording the intensity and position of X-ray diffraction patterns within a nanosecond period. A prototype detector system equipped with an ultrafast application-specific integrated circuit, field-programmable gate arrays and network processor boards was fabricated. It allowed a high count-rate of >107 cps per channel with a synchrotron X-ray beam; however, the time resolution was limited to 10 ns. The detector successfully recorded small-angle X-ray scattering by scanning the detector position.

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

2013-12-01

194

Low-background detector arrays for infrared astronomy  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

195

A Study on the CdZnTe Array Detector  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

196

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

PubMed Central

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

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

2012-01-01

197

Highly-Permissible Alignment Tolerance of Back-Illuminated Photo-Diode Array Attached with a Self-Aligned Micro Ball Lens  

NASA Astrophysics Data System (ADS)

Simulation and fabrication results on back-illuminated 4-channel photodiode (PD) array with a self-aligned micro ball lens are described. The channel pitch and diameter of each photosensitive area are 250?m and 40?m, respectively. Measured photocurrent is 1.92 times larger than that without a lens. Alignment tolerance between the single mode fiber (SMF) optical axis and the photodiode is improved from 21.2?m to 42.7?m. Moreover, the separation tolerance between the fiber and the lens is 210.5?m. These large tolerances agree with simulation results, demonstrating that the device configuration is suitable for receivers for multi-channel inter-connection. Frequency response and inter-channel cross talk are also discussed.

Nishide, Kazuhiro; Ikeda, Kenji; Song, Xueliang; Wang, Shurong; Nakano, Yoshiaki

198

A 1024×1 linear photodiode array sensor with fast readout speed flexible pixel-level integration time and high stability to UV light exposure  

NASA Astrophysics Data System (ADS)

In this paper, we demonstrate two types of new photodiode array (PDA) with fast readout speed and high stability to ultraviolet (UV) light exposure. One is a high full well capacity sensor specialized for absorption spectroscopy, the other one is a high sensitivity sensor for emission spectroscopy. By introducing multiple readout paths along the long side of the rectangle PD, both two PDAs have achieved more than 150 times faster readout speed compared with a general PDA structure with a single readout path along the short side of PD. By introducing a photodiode (PD) structure with a thin and steep dopant profile p+ layer formed on a flattened Si surface, a higher stability of the light sensitivity to UV light exposure was confirmed compared with a general PD structure for conventional PDAs.

Akutsu, Takahiro; Kawada, Shun; Koda, Yasumasa; Nakazawa, Taiki; Kuroda, Rihito; Sugawa, Shigetoshi

2014-03-01

199

Microwave detector response of the Josephson junction arrays  

SciTech Connect

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

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

1991-03-01

200

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

201

Large gamma-ray detector arrays and electromagnetic separators  

NASA Astrophysics Data System (ADS)

The use of large gamma-ray detector arrays with electromagnetic separators is a powerful combination. Various types of gamma-ray detectors have been used; some provide high detector efficiency such as scintillation detector array, others use Ge detectors for good energy resolution, and recently developed Ge energy tracking arrays gives both high peak-to-background ratio and position resolution. Similarly, different types of separators were used to optimize the performance under different experimental requirements and conditions. For example, gas-filled separators were used in heavy element studies for their large efficiency and beam rejection factor. Vacuum separators with good isotope resolution were used in transfer and fragmentation reactions for the study of nuclei far from stability. This paper presents results from recent experiments using gamma-ray detector arrays in combination with electromagnetic separators, and discusses the physics opportunities provided by these instruments. In particular, we review the performance of the instruments currently in use, and discuss the requirements of instruments for future radioactive beam accelerator facilities.

Lee, I.-Yang

2013-12-01

202

Photon-counting detector arrays based on microchannel array plates  

Microsoft Academic Search

The recent development of the channel electron multiplier (CEM) and its miniaturization into the microchannel array plate (MCP) offers the possibility of fully combining the advantages of the photographic and photoelectric detection systems. The MCP has an image-intensifying capability and the potential of being developed to yield signal outputs superior to those of conventional photomultipliers. In particular, the MCP has

J. G. Timothy

1975-01-01

203

Integrated Miniature Arrays of Optical Biomolecule Detectors  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

204

Fully tileable photodiode matrix for medical imaging by using through-wafer interconnects  

NASA Astrophysics Data System (ADS)

This paper presents a technology for a fully tileable two-dimensional (2D) photodiode matrix for medical imaging, specifically X-ray computed tomography (CT). A key trend in the CT industry is to build machines with larger area detector to speed up the measurements and to avoid image blurring due to patient movement during scanning. In current CT detector constructions, a major limiting factor in providing more detector coverage is the need to read out the signals from the individual photo-detector elements of the detector array through lines along the surface facing the radiation source and wire bonds down to a substrate or to an electronics chip. Using this method, there is a physical limitation on the size of a photo-detector array that may be manufactured. A photo-detector with the possibility of expansion in all directions is known as a 'tileable' detector. A technology of integrating through-wafer interconnects (TWIs) with traditional front illuminated photodiodes is introduced. Photocurrent can be read out from back side of the photodiode chip through interconnects, giving possibility of constructing arbitrarily large area of photo-detector for CT machine. Results of a sample 2D demonstrator detector array are presented showing that the requirements of modern CT systems can be met.

Juntunen, Mikko; Ji, Fan; Henttinen, Kimmo; Luusua, Ismo; Hietanen, Iiro; Eränen, Simo

2007-10-01

205

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

206

AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors  

NASA Astrophysics Data System (ADS)

This paper describes the proposed AIGO detector for the worldwide array of interferometric gravitational wave detectors. The first part of the paper summarizes the benefits that AIGO provides to the worldwide array of detectors. The second part gives a technical description of the detector, which will follow closely the Advanced LIGO design. Possible technical variations in the design are discussed.

Barriga, P.; Blair, D. G.; Coward, D.; Davidson, J.; Dumas, J.-C.; Howell, E.; Ju, L.; Wen, L.; Zhao, C.; McClelland, D. E.; Scott, S. M.; Slagmolen, B. J. J.; Inta, R.; Munch, J.; Ottaway, D. J.; Veitch, P.; Hosken, D.; Melatos, A.; Chung, C.; Sammut, L.; Galloway, D. K.; Marx, J.; Whitcomb, S.; Shoemaker, D.; Hughes, S. A.; Reitze, D. H.; Iyer, B. R.; Dhurandhar, S. V.; Souradeep, T.; Unnikrishnan, C. S.; Rajalakshmi, G.; Man, C. N.; Heidmann, A.; Cohadon, P.-F.; Briant, T.; Grote, H.; Danzmann, K.; Lück, H.; Willke, B.; Strain, K. A.; Sathyaprakash, B. S.; Cao, J.; Cheung, Y.-K. E.; Zhang, Y.

2010-04-01

207

Integrated uncooled infrared detector imaging arrays  

Microsoft Academic Search

The authors describe a new type of infrared (IR) focal plane consisting of a 2-D array of microminiature bolometers (microbolometers) fabricated, complete with readout electronics, as a monolithic silicon chip. These focal planes require no cooling for sensitive detection of IR radiation. The authors report high-quality IR imaging obtained with such focal planes

R. A. Wood; C. J. Han; P. W. Kruse

1992-01-01

208

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

209

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

210

Development of uncooled focal plane detector arrays for smart IR sensors  

Microsoft Academic Search

This paper reports on the development of silicon microbolometer uncooled IR focal plane detector arrays at the Defence Science and Technology Organization (DSTO), in collaboration with the National Defence Research Establishment (FOA). The detector arrays were designed by Electro-optic Sensor Design, which also provided specialist scientific advice on array fabrication. Detector arrays are prepared by monolithic processing at DSTO, using

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

1997-01-01

211

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

2011-04-15

212

Electrode array detector for microchip capillary electrophoresis.  

PubMed

Selectivity and resolution for analyses conducted using microfluidic devices can be improved by increasing the total number of individual detection elements in the device. Here, a poly(dimethylsiloxane) capillary electrophoresis microchip was fabricated with an integrated electrode array for selective detection of small molecules. Eight individually addressable gold electrodes were incorporated in series after a palladium current decoupler in the separation channel of an electrophoresis microchip. The electrode array device was characterized using a mixture of biologically relevant analytes and xenobiotics: norepinephrine, 4-aminophenol, acetaminophen, uric acid, and 3,4-dihydroxyphenylacetic acid. Separation efficiencies as high as 9000 +/- 1000 plates (n = 3) for 3,4-dihydroxyphenylacetic acid and limits of detection as low as 2.6 +/- 1.2 microM (n = 3) for norepinephrine were obtained using this device. After characterizing the performance of the device, potential step detection was conducted at the array electrodes and selective detection achieved based upon differences in redox potentials for individual analytes. Utilization of potential step detection was particularly advantageous for resolving co-migrating species; resolution of 3,4-dihydroxy-l-phenylalanine from acetaminophen using potential control was demonstrated. Finally, a human urine sample was analyzed using potential step detection to demonstrate the applicability of this device for complex sample analysis. PMID:19238284

Holcomb, Ryan E; Kraly, James R; Henry, Charles S

2009-03-01

213

An Event Reconstruction Method for the Telescope Array Fluorescence Detectors  

NASA Astrophysics Data System (ADS)

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.; Fukushima, M.; Hayashi, K.; Honda, K.; Ikeda, D.; Ishimori, R.; Kobayashi, Y.; Ogio, S.; Sagawa, H.; Takahashi, Y.; Tameda, Y.; Tokuno, H.; Tomida, T.; Tsunesada, Y.; Udo, S.; Yamazaki, K.

2011-09-01

214

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

215

Application of a single area array detector for acquistion, tracking and point-ahead in space optical communications  

NASA Technical Reports Server (NTRS)

Functions of acquisition, tracking, and point-ahead in space optical communications are being combined into a single system utilizing an area array detector. An analysis is presented of the feasibility concept. The key parameters are: optical power less than 1 pW at 0.86 micrometer, acquisition in less than 30 seconds in an acquisition field of view (FOV) of 1 mrad, tracking with 0.5 microrad rms noise at 1000 Hz update rate, and point ahead transfer function precision of 0.25 microrad over a region of 150 microrad. Currently available array detectors were examined. The most demanding specifications are low output noise, a high detection efficiency, a large number of pixels, and frame rates over 1kHz. A proof of concept (POC) demonstration system is currently being built utilizing the Kodak HS-40 detector (a 128 x 128 photodiode array with a 64 channel CCD readout architecture which can be operated at frame rates as high as 40,000/sec). The POC system implements a windowing scheme and special purpose digital signal processing electronic for matched filter acquisition and tracking algorithms.

Clark, D. L.; Cosgrove, M.; Vanvranken, R.; Park, H.; Fitzmaurice, M.

1989-01-01

216

Application of a single area array detector for acquisition, tracking and point-ahead in space optical communications  

NASA Technical Reports Server (NTRS)

Functions of acquisition, tracking, and point-ahead in space optical communications are being combined into a single system utilizing an area array detector. An analysis is presented of the feasibility concept. The key parameters are: optical power less than 1 pW at 0.86 micrometer, acquisition in less than 30 seconds in an acquisition field of view (FOV) of 1 mrad, tracking with 0.5 microrad rms noise at 1000 Hz update rate, and point ahead transfer function precision of 0.25 microrad over a region of 150 microrad. Currently available array detectors were examined. The most demanding specifications are low output noise, a high detection efficiency, a large number of pixels, and frame rates over 1kHz. A proof of concept (POC) demonstration system is currently being built utilizing the Kodak HS-40 detector (a 128 x 128 photodiode array with a 64 channel CCD readout architecture which can be operated at frame rates as high as 40,000/sec). The POC system implements a windowing scheme and special purpose digital signal processing electronic for matched filter acquisition and tracking algorithms.

Clark, D. L.; Cosgrove, M.; Van Vranken, R.; Park, H.; Fitzmaurice, M .

1989-01-01

217

Plans for CHICOS a detector array in California High Schools  

Microsoft Academic Search

The California HIgh school Cosmic ray ObServatory, CHICOS, is a collabora-tive project involving Caltech, Cal State Northridge, UC Irvine, and local high school physics teachers to site a large array of particle detectors at high schools in the Los Angeles area. The Los Angeles basin is quite unique in that there is a very large area (> 5000 km2 )

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

2001-01-01

218

Si:Bi switched photoconducttor infrared detector array  

NASA Technical Reports Server (NTRS)

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

Eakin, C. E.

1983-01-01

219

Conceptual design of a hybrid Ge:Ga detector array  

NASA Technical Reports Server (NTRS)

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

Parry, C. M.

1984-01-01

220

Calibration and operational data for a compact photodiode detector useful for monitoring the location of moving sources of positron emitting radioisotopes  

NASA Astrophysics Data System (ADS)

D-Pace has developed a compact cost-effective gamma detector system based on technology licensed from TRIUMF [1]. These photodiode detectors are convenient for detecting the presence of positron emitting radioisotopes, particularly for the case of transport of radioisotopes from a PET cyclotron to hotlab, or from one location to another in an automated radiochemistry processing unit. This paper describes recent calibration experiments undertaken at the Turku PET Centre for stationary and moving sources of F18 and C11 in standard setups. The practical diagnostic utility of using several of these devices to track the transport of radioisotopes from the cyclotron to hotlab is illustrated. For example, such a detector system provides: a semi-quantitative indication of total activity, speed of transport, location of any activity lost en route and effectiveness of follow-up system flushes, a means of identifying bolus break-up, feedback useful for deciding when to change out tubing.

Marsland, M. G.; Dehnel, M. P.; Johansson, S.; Rajander, J.; Solin, O.; Theroux, J.; Stewart, T. M.; Christensen, T.; Hollinger, C.

2013-04-01

221

High resolution decoding of Multi-Anode Microchannel Array detectors  

NASA Technical Reports Server (NTRS)

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

Kasle, David B.; Morgan, Jeffrey S.

1991-01-01

222

Uncooled MEMS-based detector arrays for THz imaging applications  

NASA Astrophysics Data System (ADS)

We report experimental results on recently developed MEMS-based, uncooled THz detectors and imaging applications for linear focal plane arrays constructed from them. The detector incorporates a broadband micro-antenna coupled to an impedance-matched microbridge. Micro-antennas were fabricated having cut-on frequencies of 500GHz, 650GHz, and 1.5THz, each with bandwidth of several hundred GHz. Sensitivity and frequency response of the detectors is predicted to be ~6pW/?Hz (with backplane) and 7kHz, respectively, and supporting measurements of the first devices will be presented. Fully integrated 1x8 linear focal plane arrays have been assembled and will be used in on-going imaging demonstrations.

Cox, J. Allen; Higashi, R.; Nusseibeh, F.; Newstrom-Peitso, K.; Zins, C.; Osiander, R.; Lehtonen, J.; Dodson, E.

2009-05-01

223

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

224

The NSLS 100 element solid state array detector  

SciTech Connect

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

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

1991-12-31

225

The NSLS 100 element solid state array detector  

SciTech Connect

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

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

1991-01-01

226

Avalanche photodiode arrays for a high-angular resolution X-ray and gamma-ray imaging telescopes  

Microsoft Academic Search

Avalanche photodiodes (APDs) have been investigated as the basis for a very high angular resolution coded aperture telescope with sensitivity over a wide energy range. Using custom electronics, software and a unique shadow-masking technique, we have achieved angular resolution from an X-ray point source of about 30arcsec. In addition we have demonstrated imaging of higher gamma-ray energies by coupling to

M. R. Squillante; R. A. Myers; F. Robertson; R. Farrell; J. F. Christian; G. Entine

2007-01-01

227

Absolute calibration of soft x-ray detectors (photocathodes, XUV photodiodes, thinned CCD, ...) with the synchrotron radiation of SUPER ACO at the LURE, Orsay  

NASA Astrophysics Data System (ADS)

To interpret the experimental results in laser matter interaction experiments, the absolute spectral response of soft x-ray detectors is often needed. For this purpose CEL-V uses calibration lines of synchrotron radiation of SUPER-ACO at the LURE. The energy of output photons can be selected from 50 eV to 1000 eV. The output photon flux is absolutely calibrated with a bolometer or a soft x-ray photodiode. Then we measure the response of the studied detector installed at the same location. Measurements of quantum efficiencies of photocathodes (Al and CsI on Al) and of the response of a thinned CCD are presented versus photon energy.

Reverdin, C.; Troussel, P.; Bourgade, J. L.; Le Guern, F.; Mens, A.; Schirmann, D.; Dalmasso, J. M.; Gontier, D.; Mazataud, D.

1994-10-01

228

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

229

Analysis of xanthene dyes by reversed-phase high-performance liquid chromatography on a polymeric column followed by characterization with a diode array detector.  

PubMed

A high-performance liquid chromatographic method on a polymeric column was developed for the analysis of xanthene dyes. The rigid polystyrene-divinylbenzene column was connected to a photodiode array detector to verify the identity and the purity of the dyes. For eosin Y a within-day precision of 1-2% was obtained, and on a day-to-day basis the coefficient of variation was 4.2%. The purity of commercial xanthene dyes was investigated, and the results show the divergence between the actual dye contents and the dye contents indicated on the label. PMID:2384549

Van Liedekerke, B M; De Leenheer, A P

1990-06-01

230

Noise correlation and decorrelation in arrays of bolometric detectors  

NASA Astrophysics Data System (ADS)

Bolometers are phonon mediated detectors used in particle physics experiments to search for rare processes, such as neutrinoless double beta decay and dark matter interactions. They feature an excellent energy resolution, which is a few keV over an energy range extending from a few keV up to several MeV. Nevertheless the resolution can be limited by the noise induced by vibrations of the mechanical apparatus. In arrays of bolometers part of this noise is correlated among different detectors and can be removed using a multichannel decorrelation algorithm. In this paper we present a decorrelation method and its application to data from the CUORICINO experiment, an array of 62 TeO2 bolometers.

Mancini-Terracciano, C.; Vignati, M.

2012-06-01

231

A high-efficiency Si-detector array for HELIOS  

NASA Astrophysics Data System (ADS)

HELIOS at ATLAS consists of a large superconducting solenoid with its magnetic axis aligned with the beam. Light charged particles emitted from the target are bent in helical orbits back to the axis where their energy and point of impact are measured by a position-sensitive Si-detector array to fully characterize two-body reactions [1]. Using an array assembled from a set of 24 Si wafers from an earlier project, this spectrometer has been in operation since August 2008 [2,3]. We will discuss the challenges in designing a new, optimized Si detector configuration that simultaneously allows for the beam to enter the spectrometer through a large bore in the upstream array, kinematic recoil detection through the bore of the downstream array, liquid cooling of the Si wafers, optimal efficiency, and the possibility of replacing individual Si wafers in the case of failure. [1] A.H. Wuosmaa et al., Nucl. Inst. Meth. A 580, 1290 (2007) [2] B.B. Back et al., Phys. Rev. Lett. 104, 132501 (2010) [3] J.C. Lighthall et al., Submitted to Nucl. Instr. Meth. (May 2010)

Back, B. B.; Digiovine, B.; Heimsath, S.; James, A. M.; Hoffman, C. R.; Kay, B. P.; Rogers, A. M.; Schiffer, J. P.; Wuosmaa, A. H.; Lighthall, J. C.; Marley, S. T.

2010-11-01

232

Imaging MAMA detector systems. [Multi-Anode Microchannel Array  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

233

The Telescope Array Middle Drum fluorescence detector simulation on GPUs  

NASA Astrophysics Data System (ADS)

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

Abu-Zayyad, Tareq; Telescope-Array Collaboration

2014-06-01

234

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

Microsoft Academic Search

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

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

235

Autofocus technique for three-dimensional imaging, direct-detection laser radar using Geiger-mode avalanche photodiode focal-plane array.  

PubMed

An autofocus technique is proposed for a three-dimensional imaging, direct-detection laser radar system that uses a Geiger-mode avalanche photodiode focal plane array (GmAPD-FPA). This technique is implemented by pointing laser pulses on a target of interest and observing its scattered photon distribution on a GmAPD-FPA. Measuring the standard deviation of the photon distribution on a GmAPD-FPA enables the best focus condition to be found. The feasibility of this technique is demonstrated experimentally by employing a 1 × 8 pixel GmAPD-FPA. It is shown that the spatial resolution improves when the GmAPD-FPA is located in the best focus position found by the autofocus technique. PMID:21165141

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

2010-12-15

236

Multicolor focal plane array detector technology: a review  

NASA Astrophysics Data System (ADS)

A major concern today is to accurately measure CO2, O3, H2O, and CH4 in the atmosphere for the prediction of climate and weather. These measurements are critical for understanding the Earth's atmosphere, atmospheric chemistry, and systemic forcing driving climactic changes. For these measurements, detectors with high quantum efficiency and near background limited performance detectivity over a wide wavelength range are necessary. In this article, we will review the state-of-the-art single and multicolor detector technologies in a wide spectral-range, for use in space-based and airborne remote sensing applications. Simultaneous detection in multi-wavelength bands with a single focal plane array (FPA) will result in reduction or elimination of heavy and complex optical components now required for wavelength differentiation in atmospheric remote sensors leading to smaller, lighter, simpler instruments with higher performance. Discussions are focused on current and the most recently developed FPA in addition to emphasizing future development in UV-to-Far infrared multicolor FPA detectors for next generation space-based instruments to measure water vapor and greenhouse gases. This novel detector component will make instruments designed for these critical measurements more efficient while reducing complexity and associated electronics and weight. Finally, we will discuss the on-going detector technology efforts at NASA Langley Research Center (LaRC), Jet Propulsion Laboratory (JPL), and Rensselaer Polytechnic Institute (RPI).

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

2003-11-01

237

Effect of Atmospheric Turbulence on the Bit Error Probability of a Space to Ground Near Infrared Laser Communications Link Using Binary Pulse Position Modulation and an Avalanche Photodiode Detector,  

National Technical Information Service (NTIS)

The effect of atmospheric turbulence on the bit error rate of a space-to-ground near infrared laser communications link is investigated, for a link using binary pulse position modulation and an avalanche photodiode detector. Formulas are presented for the...

H. G. Safren

1987-01-01

238

Distributed Antenna-Coupled TES for FIR Detector Arrays  

NASA Astrophysics Data System (ADS)

We report progress toward large arrays of sensitive TES bolometers for submillimeter and far-infrared wavelengths with noise equivalent power (NEP) suitable for either imaging from a cooled space telescope or ground based spectroscopy. The arrays are based on a pixel design that makes use of a distributed transition edge sensor (TES) coupled to a slot antenna array. We have electrically characterized prototype detectors consisting of 256 TiN hot-electron TES microbolometers biased in parallel with T c =50 mK. The measured electron-phonon thermal conductance of prototype devices is as low as 1.1 pW/K at 50 mK corresponding to an electrical NEP of 4×10-19 W/Hz1/2. The time constant of two detectors with different geometries and transition widths was measured under a range of bias conditions. We have measured time constants ?10-3 seconds, which is long enough for straightforward multiplexing with existing multiplexer technology.

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

2008-04-01

239

Bolometric Array Detectors for Space-Borne Astronomy  

NASA Technical Reports Server (NTRS)

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

Lange, Andrew E.

2000-01-01

240

Fast, High-Precision Readout Circuit for Detector Arrays  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

241

Novel Multiplexing Technique for Detector and Mixer Arrays  

NASA Technical Reports Server (NTRS)

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

Karasik, Boris S.; McGrath, William R.

2001-01-01

242

Development of a fast analytical method for the determination of sudan dyes in chili- and curry-containing foodstuffs by high-performance liquid chromatography-photodiode array detection.  

PubMed

A simple and fast analytical method for the determination of sudans I, II, III, and IV in chili- and curry-containing foodstuffs is described. These dyes are extracted from the samples with acetonitrile and analyzed by high-performance liquid chromatography coupled to a photodiode array detector. The chromatographic separation is carried out on a reverse phase C18 column with an isocratic mode using a mixture of acetonitrile and water. An "in-house" validation was achieved in chili- and curry-based sauces and powdered spices. Depending on the dye, limits of detection range from 0.2 to 0.5 mg/kg in sauces and from 1.5 to 2 mg/kg in spices. Limits of quantification are between 0.4 and 1 mg/kg in sauces and between 3 and 4 mg/kg in spices. Validation data show a good repeatability and within-lab reproducibility with relative standard deviations < 15%. The overall recoveries are in the range of 51-86% in sauces and in the range of 89-100% in powdered spices depending on the dye involved. Calibration curves are linear in the 0-5 mg/kg range for sauces and in the 0-20 mg/kg range for spices. The proposed method is specific and selective, allowing the analysis of over 20 samples per working day. PMID:16448161

Cornet, Vanessa; Govaert, Yasmine; Moens, Goedele; Van Loco, Joris; Degroodt, Jean-Marie

2006-02-01

243

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

244

Undersampling Correction for Array Detector-Based Satellite Spectrometers  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

245

Cerenkov radiators for photodiodes  

SciTech Connect

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

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

1982-01-01

246

Photon-counting detector arrays based on microchannel array plates. [for image enhancement  

NASA Technical Reports Server (NTRS)

The recent development of the channel electron multiplier (CEM) and its miniaturization into the microchannel array plate (MCP) offers the possibility of fully combining the advantages of the photographic and photoelectric detection systems. The MCP has an image-intensifying capability and the potential of being developed to yield signal outputs superior to those of conventional photomultipliers. In particular, the MCP has a photon-counting capability with a negligible dark-count rate. Furthermore, the MCP can operate stably and efficiently at extreme-ultraviolet and soft X-ray wavelengths in a windowless configuration or can be integrated with a photo-cathode in a sealed tube for use at ultraviolet and visible wavelengths. The operation of one- and two-dimensional photon-counting detector arrays based on the MCP at extreme-ultraviolet wavelengths is described, and the design of sealed arrays for use at ultraviolet and visible wavelengths is briefly discussed.

Timothy, J. G.

1975-01-01

247

A YSO\\/LSO phoswich array detector for single and coincidence photon imaging  

Microsoft Academic Search

The performance of a phoswich array detector module for possible use in a combined single and coincidence photon imaging system has been evaluated. The detector consist of a linear array of discrete 4×4×15 mm3 YSO elements coupled to a combined detector array\\/light guide of LSO, 10 mm thick. Since the scintillation light decay time is different in YSO and LSO

M. Dahlbom; L. R. MacDonald; M. Schmand; L. Eriksson; M. Andreaco; C. Williams

1998-01-01

248

Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry  

NASA Astrophysics Data System (ADS)

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

Bock, James

2014-01-01

249

Design of a CMOS Potentiostat Circuit for Electrochemical Detector Arrays  

PubMed Central

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

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

2010-01-01

250

Geant4 simulation of backgrounds in a p-type point contact Ge detector array  

Microsoft Academic Search

Plans are currently underway to construct an array of P-type Point Contact (PPC) Ge detectors for the Majo-ra-na neutrinoless double beta decay experiment. An important aspect of any ultra-low background detector design is estimating the background due to the detectors, associated small parts and cables, and the cryostat components. To this end, the current detector array design has been implemented

M. Boswell

2008-01-01

251

IDENTIFICATION AND QUANTITATION OF ALKYLATED NUCLEOBASIS BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH UV PHOTODIODE ARRAY DETECTION  

EPA Science Inventory

The application of UV diode array detection in high-performance liquid chromatographic (HPLC) identification and quantitation of several classes of synthetic and commercially available alkylated nucleobases is investigated. uantitative spectral overlays of these compounds to meth...

252

Nova photodiode cooling undergraduate Research  

NASA Astrophysics Data System (ADS)

Nova, an experiment that will study oscillation of neutrinos and ordering of neutrino masses, consists of a 200-ton detector on the Fermilab site (near detector) and a 14,000 ton detector in Northern Minnesota (far detector). These detectors require a massive amount of photodetectors (12,500 in all), called Hamamatsu Avalanche Photodiodes (APDs). These APDs require a stable temperature of -15C. I will describe tests of heat sink and thermoelectric cooler (TEC) designs (taken at Indiana University) to meet specifications for the APDs. These tests were done as a student in an REU (Research Experience for Undergraduates) during the summer of 2009.

Meyer, Benjamin

2010-01-01

253

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

NASA Technical Reports Server (NTRS)

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

Ando, K. J.

1978-01-01

254

Method of fabricating multiwavelength infrared focal plane array detector  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

255

Characterization of area arrays of microbolometer-based un-cooled IR detectors without using ROIC  

Microsoft Academic Search

We present the characterization of microbolometer area arrays being developed for IR imaging applications. Here, we propose a technique that does not use readout integrated circuit for accessing detector array elements for characterization, which is useful for initial detector technology development. The technique is based on a connection scheme that uses two levels of metal lines in a row–column fashion,

R. S. Saxena; R. K. Bhan; C. R. Jalwania; P. S. Rana; S. K. Lomash

2008-01-01

256

Photodiode-Coupled Light Modulator  

NASA Technical Reports Server (NTRS)

Absorption of one light beam controls transmission of another. High-performance monolithic light modulator comprised of p-doped/intrinsic/n-doped (PIN) GaAs photodiode grown directly over InAs/GaAs PIN multiple-quantum-well (MQW) diode. Photodiode-coupled multiple-quantum-well modulator includes advanced semi-conductor microstructures enhancing electro-optical properties. Using standard lithographic and etching techniques for defining picture elements, structures fabricated into two-dimensional arrays for use as spatial light modulators.

Maserjian, Joseph; Eng, Sverre T.

1989-01-01

257

Energy spectrum measured by the telescope array surface detector  

NASA Astrophysics Data System (ADS)

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

Ivanov, Dmitri

2012-05-01

258

Identification and analysis of alkaloids in cortex Phellodendron amurense by high-performance liquid chromatography with electrospray ionization mass spectrometry coupled with photodiode array detection.  

PubMed

Alkaloids from Cortex Phellodendron amurense Rupr. were identified to determine the material basis for the bioactivity of this herb. HPLC-ESI-MS with photodiode array detection coupled to XCharge C18 column was applied to analyze the alkaloids qualitatively and quantitatively. A total of 37 alkaloids were identified and tentatively characterized from the ethanol extract by online ESI-MS(n) fragmentation and UV spectral analysis. A total of ten alkaloids, including four novel natural products, were tentatively identified for the first time in P. amurense. The fragmentation pathways for certain compounds were analyzed. The contents of a pair of isomers (columbamine and jatrorrhizine) and four main alkaloids (phellodendrine, magnoflorine, berberine, and palmatine) were simultaneously quantified using the aforementioned method. Results showed that the newly discovered and known components of P. amurense were helpful in determining the material basis for the bioactivity of the herb. The application of the XCharge C18 column is a suitable and practical method for the isolation of alkaloids in plants. PMID:24723373

Xian, Xiaoyan; Sun, Bohang; Ye, Xueting; Zhang, Guanying; Hou, Pengyi; Gao, Huiyuan

2014-07-01

259

Advanced ultra-performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometric methods for simultaneous screening and quantification of triterpenoids in Poria cocos.  

PubMed

A sensitive, precise and accurate method was developed to screen and quantify triterpenoids based on ultra-performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry (UPLC-PDA-QTOF-MS). An exact neutral loss scan of 62.0004 Da (CH2O3) was used to selectively detect triterpenoids in Poria cocos, followed by a survey scan for exact masses of precursor and fragment ions of these triterpenoids. The developed method was applied to quantify seven major triterpenoids in 40 P. cocos samples of different origins within 18 min, and a total of 31 triterpenoids were unequivocally or tentatively identified. Principal component analysis of these samples showed a clear separation of three groups, and ten triterpenoids play key roles in differentiating these samples were obtained from the OPLS-DA variable influence on projection (VIP) plot and then unequivocally or tentatively identified. The developed method can be applied for rapid bitterness evaluation, quality control and authenticity establishment of P. cocos. PMID:24444932

Xia, Bing; Zhou, Yan; Tan, Hong Sheng; Ding, Li Sheng; Xu, Hong Xi

2014-06-01

260

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

PubMed

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

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

2007-03-14

261

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

262

Fingerprinting and simultaneous determination of alkaloids in Picrasma quassioides from different locations by high performance liquid chromatography with photodiode array detection.  

PubMed

A simple and sensitive method was developed and validated for profiling and simultaneous quantitation of seven alkaloids (6-hydroxy-?-carboline-1-carboxylic acid, ?-carboline-1-carboxylic acid, ?-carboline-1-propanoic acid, 3-methylcanthin-5,6-dione, 5-hydroxy-4-methoxycanthin-6-one, 1-methoxycarbony-?-carboline, and 4,5-dimethoxycanthin-6-one) in Picrasma quassioide grown in different locations by high-performance liquid chromatography with photodiode array detection. The analysis was conducted on a Phenomenex Gemini C(18) column at 35°C with mobile phase of 25 mM aqueous ammonium acetate (pH 4.0, adjusted by glacial acetate acid) and acetonitrile. A common fingerprint chromatograph under 254 nm consisting of 27 peaks was constructed for the evaluation of the similarities among 31 P. quassioide samples. Samples from Guangdong and Guangxi Provinces were found to be within group linkage and showed significant difference from that of Jiangxi Province origin by using principal component analysis and hierarchical clustering analysis. In addition, the seven alkaloids were identified by electrospray ionization mass spectrometry and comparing with reference standards and literature data. All of them were determined simultaneously using the established HPLC method. This rapid and effective analytical method could be employed for quality assessment of P. quassioide, as well as pharmaceutical products containing this herbal material. PMID:22888096

Liao, Hui-Jun; Lai, Zheng-Quan; Su, Ji-Yan; Yi, Yu-Yang; Li, Yu-Cui; Lai, Xiao-Ping; Su, Zi-Ren; Lin, Zhi-Xiu

2012-09-01

263

Simultaneous determination of liquiritin, hesperidin, and glycyrrhizin by HPLC-photodiode array detection and the anti-inflammatory effect of Pyungwi-san.  

PubMed

A high-performance liquid chromatographic method was developed and validated to determine liquiritin, hesperidin, and glycyrrhizin levels in a traditional Korean medicine, Pyungwi-san (PWS). Reverse-phase chromatography using a C18 column operating at 40oC, and photodiode array detection at 254 nm and 280 nm, were used for quantification of the three marker components of PWS. The mobile phase using gradient flow consisted of two solvent systems. Solvent A was 1.0% (v/v) aqueous acetic acid and solvent B was acetonitrile with 1.0% (v/v) acetic acid. Calibration curves were acquired with r (2) > 0.9999, and the relative standard deviation values (%) for intra- and inter-day precision were both less than 4.0%. The recovery of each compound was in the range 97.33-110.72%, with an relative standard deviation less than 6.0%. To provide information on the biological activity of PWS, anti-inflammatory action was evaluated. Production of nitric oxide and prostaglandin E(2) were measured using the Griess reagent and enzyme-linked immunosorbent assay, respectively. PWS showed inhibitory effect on prostaglandin E(2) production in LPS-treated RAW 264.7 cells. PMID:21380802

Seo, Chang Seob; Lee, Jin-Ah; Jung, Dayoung; Lee, Ho-Young; Lee, Jun Kyoung; Ha, Hyekyung; Lee, Mee-Young; Shin, Hyeun Kyoo

2011-02-01

264

Cimicifuga species identification by high performance liquid chromatography-photodiode array/mass spectrometric/evaporative light scattering detection for quality control of black cohosh products.  

PubMed

Black cohosh has become one of the most important herbal products in the US dietary supplements market. It is manufactured from roots and rhizomes of Cimicifuga racemosa (Ranunculaceae). Botanical identification of the raw starting material is a key step in the quality control of black cohosh preparations. The present report summarizes a fingerprinting approach based on high performance liquid chromatography-photodiode array/mass spectrometric/evaporative light scattering detection (HPLC-PDA/MS/ELSD) that has been developed and validated using a total of 10 Cimicifuga species. These include three North American species, Cimicifuga racemosa, Cimicifuga americana, Cimicifuga rubifolia, and seven Asian species, Cimicifuga acerina, Cimicifuga biternat, Cimicifuga dahurica, Cimicifuga heracleifolia, Cimicifuga japonica, Cimicifuga foetida, and Cimicifuga simplex. The chemotaxonomic distinctiveness of the HPLC fingerprints allows identification of all 10 Cimicifuga species. The triterpene glycoside cimigenol-3-O-arabinoside (3), cimifugin (12), and cimifugin-3-O-glucoside (18) were determined to be suitable species-specific markers for the distinction of C. racemosa from the other Cimicifuga species. In addition to identification, the fingerprint method provided insight into chemical interconversion processes occurring between the diverse triterpene glycosides contained in black cohosh. The reported method has proven its usefulness in the botanical standardization and quality control of black cohosh products. PMID:16515793

He, Kan; Pauli, Guido F; Zheng, Bolin; Wang, Huikang; Bai, Naisheng; Peng, Tangsheng; Roller, Marc; Zheng, Qunyi

2006-04-21

265

Status of uncooled focal plane detector arrays for smart IR sensors  

NASA Astrophysics Data System (ADS)

A cooperative research project between the Defense Science and Technology Organization, Australia, and the National Defense Research Establishment, Sweden, seeks to investigate concepts for smart IR focal plane detector arrays, whereby a monolithic Semiconductor Film Bolometer detector array is integrated with a CMOS signal conditioning circuit, analog- to-digital conversion and signal processing functions on the same silicon chip. Novel signal conditioning and on-chip digital readout techniques have been successfully demonstrated, and the supporting signal processing electronic design is being developed. This paper discusses the status of detector materials research and staring focal plane array development. The first experimental array has been delivered and is undergoing evaluation.

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

1996-06-01

266

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

NASA Astrophysics Data System (ADS)

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

Wikner, David; Grossman, Erich

2009-05-01

267

Development and Test of Multi-Anode Microchannel Array Detector Systems. Part 2. Soft X-ray Detectors.  

National Technical Information Service (NTIS)

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 wi...

J. G. Timothy

1986-01-01

268

Spectral reflectance of silicon photodiodes.  

PubMed

A precision spectrometer was used to measure the spectral reflectance of a silicon photodiode over the wavelength range from 250 to 850 nm. The results were compared with the corresponding values predicted by a model based on thin-film Fresnel formulas and the known refractive indices of silicon and silicon dioxide. The good agreement at the level of 2 x 10(-3) in the visible wavelength range verifies that the reflection model can be used for accurate extrapolation of the spectral reflectance and responsivity of silicon photodiode devices. In addition, characterization of the photodiode reflectance in the ultraviolet region improves the accuracy of the spectral irradiance measurements when filter radiometers based on trap detectors are used. PMID:18268645

Haapalinna, A; Kärhä, P; Ikonen, E

1998-02-01

269

In-orbit performance of avalanche photodiode as radiation detector onboard a pico-satellite Cute-1.7+APD II  

NASA Astrophysics Data System (ADS)

Cute-1.7+APD II is the third pico-satellite developed by students at the Tokyo Institute of Technology. One of the primary goals of the mission is to validate the use of avalanche photodiodes (APDs) as a radiation detector for the first time in a space experiment. The satellite was successfully launched by an ISRO PSLV-C9 rocket in Apr 2008 and has since been in operation for more than 20 months. Cute-1.7+APD II carries two reversetype APDs to monitor the distribution of low energy particles down to 9.2 keV trapped in a Low Earth Orbit (LEO), including 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-hour observations, will be presented to demonstrate the initial flight performance of the APDs in orbit.

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

2010-07-01

270

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

271

Delta-Doped CCDs as Detector Arrays in Mass Spectrometers  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

272

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

273

[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

274

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

NASA Technical Reports Server (NTRS)

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

Timothy, J. G.

1984-01-01

275

Focal plane arrays: Technology and applications; Proceedings of the Meeting, Cannes, France, Nov. 19, 20, 1987  

NASA Astrophysics Data System (ADS)

Focal plane array (FPA) technology is reviewed, and astrophysical and space applications of FPAs are described. Particular papers are presented on a CCD for SWIR photodiode multiplexing, the performance of a thermal imager using a hybrid pyroelectric detector array with MOSFET readout, a near-IR focal FPA for the Infrared Space Observatory camera (ISOCAM), FPAs for the ISOPHOT experiment, and performance measurements on a 32x32 InSb charge inspection device detector array for astronomical observations.

Chatard, Jean-Pierre

276

Method of fabricating a PbS-PbSe IR detector array  

NASA Technical Reports Server (NTRS)

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

Barrett, John R. (Inventor)

1987-01-01

277

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

278

Monte Carlo simulation of the standardization of 22Na using scintillation detector arrays.  

PubMed

In order to calibrate PET devices by a sealed point source, we contrived an absolute activity measurement method for the sealed point source using scintillation detector arrays. This new method was verified by EGS5 Monte Carlo simulation. PMID:20083411

Sato, Y; Murayama, H; Yamada, T; Hasegawa, T; Oda, K; Unno, Y; Yunoki, A

2010-01-01

279

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

280

Development of a Gamma-ray Burst Detector Based on the Silicon Drift Detector Array and Scintillators  

SciTech Connect

We propose a gamma-ray burst (GRB) detector combining the silicon drift detector (SDD) array and scintillators with broadband X-ray and gamma-ray coverage (0.5-1000 keV or more), high energy resolution (2-10%) and high time resolution ({approx}{mu}s) in space. To realize such compact high-performance detector without photomultiplier tubes, we constructed proto-type model using KETEK SDD with a detection area of 1 cm{sup 2} and BGO crystal. The detector shows a very good performance. Obtained FWHM energy resolution was 191 eV at 5.9 keV in the SDD, while 6.5 % at 662 keV in the BGO at -30 deg. C. Evaluation of the 7 channel SDD array and development of analog ASIC for its readout are also presented.

Yamaoka, Kazutaka; Arai, Yusuke; Doshida, Takaaki; Watanabe, Tsuyoshi; Tsutsui, Akihito; Asano, Satoshi; Yoshida, Kotaro; Yoshida, Atsumasa [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 229-8558 (Japan); Pahlke, Andreas [KETEK GmbH, Hofer Strasse 3, 81737 Munchen (Germany); Ikeda, Hirokazu; Takahashi, Tadayuki [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Mori, Kunishiro [Clear Pulse Ltd, 6-25-17 Chuoh, Ohta-ku, Tokyo 143-0024 (Japan); Kato, Hiroshi [Makishima Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2008-05-22

281

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

DOEpatents

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

Enke, Christie

2013-02-19

282

On site calibration for new fluorescence detectors of the telescope array experiment  

NASA Astrophysics Data System (ADS)

The Telescope Array experiment is searching for the origin of ultra-high energy cosmic rays using a ground array of particle detectors and three fluorescence telescope stations. The precise calibration of the fluorescence detectors is important for small systematic errors in shower reconstruction. This paper details the process of calibrating cameras for two of the fluorescence telescope stations. This paper provides the operational results of these camera calibrations.

Tokuno, H.; Murano, Y.; Kawana, S.; Tameda, Y.; Taketa, A.; Ikeda, D.; Udo, S.; Ogio, S.; Fukushima, M.; Azuma, R.; Fukuda, M.; Inoue, N.; Kadota, K.; Kakimoto, F.; Sagawa, H.; Sakurai, N.; Shibata, T.; Takeda, M.; Tsunesada, Y.

2009-04-01

283

XRF spectrometers based on monolithic arrays of silicon drift detectors: elemental mapping analyses and advanced detector structures  

Microsoft Academic Search

This paper describes a new X-ray fluorescence spectrometer based on a ring-shaped monolithic array of silicon drift detectors (SDD), presents several examples of the application of this instrument in elemental mapping analyses and introduces a new multi-element detector based on SDDs whose structure has been specifically optimized for very high energy-resolution and very fast sample scanning in elemental mapping. The

A. Longoni; C. Fiorini; C. Guazzoni; S. Buzzetti; M. Bellini; A. Gola; L. Struder; P. Lechner; A. Bjeoumikov; J. Kemmer

2004-01-01

284

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

SciTech Connect

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

Dereniak, E.L.

1988-01-01

285

58 x 62 Si:Sb DRO infrared detector array performance (Poster)  

NASA Astrophysics Data System (ADS)

Preliminary test results from the evaluation of two 58×62 element Si:Sb infrared detector arrays produced by Hughes Aircraft Co./Santa Barbara Research Center are presented. The arrays are hybridized to silicon direct readout (DRO) multiplexers which allow random-access and non-destructive readout.

McKelvey, M. E.; Goebel, J. H.; McCreight, C. R.; Moss, N. N.

286

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

287

A Low-Complexity Multiuser Detector for Asynchronous CDMA QPSK Adaptive Antenna Array Systems  

Microsoft Academic Search

This paper proposes a low complexity joint space-time multiuser detection algorithm for asynchronous DS\\/CDMA antenna array systems. The proposed multiuser detector is composed of an adaptive antenna array, used as a linear beamformer, and a sliding window decorrelator. A QPSK modulation scheme is used in order to increase bandwidth efficiency. Numerical results are given in terms of Bit Error Rate

Enrico Del Re; Romano Fantacci; Simone Morosi; S. Marapodi

2003-01-01

288

The use of large arrays of HPGe detectors and the study of fission  

Microsoft Academic Search

The use of large arrays of detectors has gained importance in nuclear structure studies in the past decade. These arrays have added new information for the cases of high multiplicity of radiation emitted for nuclear reaction work. They have applied the criteria to experimental measurement of radiation from the fission of actinide nuclei. The current series of experiments is designed

J. D. Cole; M. W. Drigert; R. Aryaeinejad

1999-01-01

289

Si-Ga array detectors optimized for the 10?m atmospheric window (Contributed)  

NASA Astrophysics Data System (ADS)

Si-Ga DRO detector arrays, specifically designed for 10 ?m ground-based observations, are under development at the LETI/LIR. These detectors will be integrated, at the end of this year, in an IR camera currently built for INSU by the astrophysical laboratories of Lyon, Saclay and Grenoble.

Lagage, P. O.; Audaire, L.; Cesarsky, C.; Lucas, C.; Monin, J. L.; Sibille, F.

290

Brief Introduction to the ?-DETECTOR Array at Institute of Modern Physics in Lanzhou  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

291

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

292

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

293

Photodiodes array as potential diagnostic for measuring short bursts of K-? radiation from Ti targets irradiated with 45 fs laser pulses  

NASA Astrophysics Data System (ADS)

We report on a study comparing absolute K-? yield from Ti foils measured with a calibrated system of an X-ray CCD coupled to a curved LiF Von-Hamos crystal spectrometer to the difference in the signals measured simultaneously with two similar photodiodes fitted with two different filters. Our data indicate that a combination of photodiodes with different filters could be developed into an alternative and inexpensive diagnostic for monitoring single shot pulsed emission in a narrow band of X-ray region.

Khattak, F. Y.; Angulo-Gareta, J. J.; Foster, P. S.; Clarke, R. J.; Riley, D.

2006-12-01

294

Detection probabilities for photon-counting avalanche photodiodes applied to a laser radar system  

NASA Astrophysics Data System (ADS)

Arrays of photon-counting avalanche photodiodes with time-resolved readout can improve the performance of three-dimensional laser radars. A comparison of the detection and false-alarm probabilities for detectors in linear mode and in Geiger mode is shown. With low background radiation their performance is comparable. It is shown that in both cases it will be necessary to process several laser shots of the same scene to improve detection and reduce the false-alarm rate. Additional calculations show that the linear mode detector is much better at detecting targets behind semitransparent obscurations such as vegetation and camouflage nets.

Henriksson, Markus

2005-08-01

295

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

Microsoft Academic Search

Radioactive decay has long played a role in contributing to the elucidation of nuclear structure. However compared to in-beam gamma-ray spectroscopy, which has been combined with the extraordinary power of multi-detector arrays, radioactive decay scheme studies have been carried out usually with rather modest detector set-ups (two detectors, no Compton suppression). An extensive program to rectify this situation has been

John L. Wood

2000-01-01

296

Integrated filter and detector array for spectral imaging  

NASA Astrophysics Data System (ADS)

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

Labaw, Clayton C.

1991-08-01

297

Integrated filter and detector array for spectral imaging  

NASA Astrophysics Data System (ADS)

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

Labaw, Clayton C.

1992-10-01

298

Energy harvesting photodiodes with integrated 2D diffractive storage capacitance  

Microsoft Academic Search

Integrating photodiodes with logic and exploiting on-die interconnect capacitance for energy storage can enable new, low-cost energy harvesting wireless systems. To further explore the tradeoffs between optical efficiency and capacitive energy storage for integrated photodiodes, an array of photovoltaics with various diffractive storage capacitors was designed in TSMC's 90nm CMOS technology. Transient effects from interfacing the photodiodes with switching regulators

Nathaniel J. Guilar; Erin G. Fong; Travis Kleeburg; Diego R. Yankelevich; Rajeevan Amirtharajah

2008-01-01

299

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

NASA Astrophysics Data System (ADS)

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

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

1983-01-01

300

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

301

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

302

Detector Arrays for the James Webb Near Infrared Spectrograph  

NASA Technical Reports Server (NTRS)

NASA Goddard Space Flight Center is delivering the detector subsystem for the James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec). Of all JWST instruments, NIRSpec has the most stringent detector requirements. In this poster, we describe recent performance testing results and relate them to NIRSpec's science requirements.

Rauscher, Bernard J.

2009-01-01

303

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

NASA Technical Reports Server (NTRS)

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.

1986-01-01

304

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

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

305

A large underground water Cherenkov muon detector array with the Tibet air shower array for Gamma-ray astronomy in the 100 TeV region: detector design and simulation  

Microsoft Academic Search

We are planning to build a large water-Cherenkov-type muon detector array around the Tibet air shower array for Gamma-ray astronomy in the 100 TeV Region. In this paper, we describe the design of the Tibet MD array and details of the Monte Carlo simulation to demonstrate the sensitivity of the Tibet AS+MD array.

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

2008-01-01

306

Waveguide biosensor with integrated detector array for tuberculosis testing  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

307

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

308

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

NASA Technical Reports Server (NTRS)

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

309

A cooled avalanche photodiode with high photon detection probability  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

310

Spectral Matching Properties between Avalanche Photodiodes and Typical Objects  

Microsoft Academic Search

Avalanche photodiode detector has come to more and more attention due to single photon detection sensitivity, low noise in night vision field. However, avalanche photodiodes (APD) made of different materials have different photon detection efficiency characteristics. The spectral matching factors were computed and analyzed based on the spectrums of night sky, Si APD & InGaAs APD and typical object under

Liju Yin; Qian Chen; Canlin Zhang

2009-01-01

311

Photodiode Read-out of CsI (Tl) Scintillators.  

National Technical Information Service (NTIS)

The photodiode read-out of CsI(Tl) scintillator detectors up to a size of 100 cm/sup 3/ was examined and developed further. In preparatory measurements with a combination of small crystals (approx. = 3 cm/sup 3/) and photodiodes with active surfaces of 1 ...

P. Kreutz

1988-01-01

312

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

313

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.

2013-12-01

314

Ultra High Flux 2-D CdZnTe Monolithic Detector Arrays for X-Ray Imaging Applications  

Microsoft Academic Search

The performance of 2-D CdZnTe monolithic detector arrays designed for high flux X-ray imaging applications was studied. For the first time we have obtained 5 times 106 counts\\/s\\/mm2 count-rate for a CdZnTe pixelated detector array. This count-rate is more than twice the highest count-rate ever achieved using a CdZnTe detector array. Such excellent performance was demonstrated for more than 600

Csaba Szeles; Stephen A. Soldner; Steve Vydrin; Jesse Graves; Derek S. Bale

2007-01-01

315

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

NASA Technical Reports Server (NTRS)

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

Kasle, David B.; Horch, Elliott P.

1993-01-01

316

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

317

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

PubMed

This paper proposes a real-time human identification system using a pyroelectric infrared (PIR) detector array and hidden Markov models (HMMs). A PIR detector array with masked Fresnel lens arrays is used to generate digital sequential data that can represent a human motion feature. HMMs are trained to statistically model the motion features of individuals through an expectation-maximization (EM) learning process. Human subjects are recognized by evaluating a set of new feature data against the trained HMMs using the maximum-likelihood (ML) criterion. We have developed a prototype system to verify the proposed method. Sensor modules with different numbers of detectors and different sampling masks were tested to maximize the identification capability of the sensor system. PMID:19516845

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

2006-07-24

318

Measurements of fibre optic power using photodiodes with and without an integrating sphere  

Microsoft Academic Search

We have studied two kinds of reference detectors to be used for calibration of fibre optic power meters. The first type consists of an InGaAs photodiode mounted directly on an adapter using a standard FC connector. In the second type, a similar photodiode is fitted into a 5 cm diameter integrating sphere. The plain photodiodes are used for low power

Jouni Envall; Petri Kärhä; Erkki Ikonen

2004-01-01

319

Performance comparison of CMOS-based photodiodes for high-resolution and high-sensitivity digital mammography  

NASA Astrophysics Data System (ADS)

In order to develop a high-resolution and high-sensitivity digital mamographic detector, to use a commercially-available and well-developed CMOS image sensor (CIS) process can be a cost-effective way. However, in any commercial CIS process, several different types of n- or p-layers can be used so that various pn-junction structures could be formed depending on the choice of n- and p-layer combination. We performed a comparative analysis on the characteristics of three types of photodiodes formed on a high-resistivity p-type epitaxial wafer by applying three available n-layer processes in order to develop the high-sensitivity photodiode for a scintillator-based X-ray imaging detector. As a preliminar study, a small test-version CIS chip with an 80 × 80 pixel array of a 3-transistor active pixel sensor structure, 50 ?m pitch and 80{%} fill factor was fabricated. The pixel area is subdivided into four 40 × 40 sub-arrays and 3 different types of photodides are designed for each sub-array by using n+, n- and n-well layers. All other components are designed to be identical for impartial comparison of the photodiodes only. Among 3 types, the n-/p-epi photodiode exhibited high charge-to-voltage gain (0.86 ?V/e-), high quantum efficiency (49% at 532 nm wavelength) and low dark current (294 pA/cm2). The test CIS chip was coupled to a phosphor screen, Lanex Fine or Lanex Regular, both composed of Gd2O2S:Tb, and was tested using X-rays in a mammography setting. Among 6 cases, n-/p-epi photodiode coupled with the Lanex Regular also showed the highest sensitivity of 30.5 mV/mR.

Bae, J. H.; Cho, M.; Kim, M. S.; Lee, D. H.; Cho, G.

2011-12-01

320

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

NASA Astrophysics Data System (ADS)

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

Ikeda, Daisuke

2013-02-01

321

IR Imaging Using Arrays of SiO2 Micromechanical Detectors  

SciTech Connect

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

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

2012-01-01

322

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

NASA Technical Reports Server (NTRS)

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

Bailey, G.

1982-01-01

323

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

324

High-efficiency microstructured semiconductor neutron detectors that are arrayed, dual-integrated, and stacked.  

PubMed

Silicon diodes with large aspect ratio 3D microstructures backfilled with 6LiF show a significant increase in neutron detection efficiency beyond that of conventional thin-film coated planar devices. Described in this work are advancements in the technology using detector stacking methods and summed-detector 6×6-element arraying methods to dramatically increase the sensitivity to thermal neutrons. The intrinsic detection efficiency of the 6×6 array for normal-incident 0.0253 eV neutrons was found 6.8% compared against a calibrated 3He proportional counter. PMID:22365111

Bellinger, Steven L; Fronk, Ryan G; Sobering, Timothy J; McGregor, Douglas S

2012-07-01

325

3D imaging LADAR with linear array devices: laser, detector and ROIC  

NASA Astrophysics Data System (ADS)

This paper introduces the recent development of 3D imaging LADAR (LAser Detection And Ranging) in Mitsubishi Electric Corporation. The system consists of in-house-made key devices which are linear array: the laser, the detector and the ROIC (Read-Out Integrated Circuit). The laser transmitter is the high power and compact planar waveguide array laser at the wavelength of 1.5 micron. The detector array consists of the low excess noise Avalanche Photo Diode (APD) using the InAlAs multiplication layer. The analog ROIC array, which is fabricated in the SiGe- BiCMOS process, includes the Trans-Impedance Amplifiers (TIA), the peak intensity detectors, the Time-Of-Flight (TOF) detectors, and the multiplexers for read-out. This device has the feature in its detection ability for the small signal by optimizing the peak intensity detection circuit. By combining these devices with the one dimensional fast scanner, the real-time 3D range image can be obtained. After the explanations about the key devices, some 3D imaging results are demonstrated using the single element key devices. The imaging using the developed array devices is planned in the near future.

Kameyama, Shumpei; Imaki, Masaharu; Tamagawa, Yasuhisa; Akino, Yosuke; Hirai, Akihito; Ishimura, Eitaro; Hirano, Yoshihito

2009-07-01

326

Measuring the ultra-high energy comic ray flux with the Telescope Array Middle Drum detector  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA) Experiment, located 200 kilometers southwest of Salt Lake City, Utah, is the largest Ultra-High Energy cosmic ray detector in the northern hemisphere. TA is a follow up to the High Resolution Fly's Eye (HiRes) and AGASA experiments, and seeks to gain insight into cosmic ray acceleration by measuring the flux of cosmic rays with energies over 10^18 eV. The detector consists of 507 scintillator counters distributed in a square grid with 1.2 km spacing. Three fluorescence detector stations sit on the corners of a 30 km equilateral triangle overlooking the array of surface detectors, and provide full hybrid coverage with the scintillator array above 10 EeV. Telescope Array underwent commissioning in 2007 and began routine data collection operations at the beginning of 2008. One of the three fluorescence stations, the Middle Drum (MD) site, is instrumented with detectors previously used at the HiRes-1 site. The inclusion of the MD site makes possible a direct comparison between the fluorescence energy scales and spectra between TA and HiRes. We will present a progress report on the analysis of the TA data collected by the MD site.

Sonley, Thomas

2009-10-01

327

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

PubMed

A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 x 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 x 0.8 x 3 mm(3) and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 x 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and +/-5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when +/-10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing among multiple MPPC and to diffuse and direct scintillation light can reduce the nonlinearity of the detector response within the limited dynamic range of a typical MPPC. As a result, the proposed PET detector module has the potential to be refined for use in high-resolution PET insert applications. PMID:20393236

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

2010-05-01

328

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

329

FPGA-based electronics for confocal line scanners with linear detector arrays  

NASA Astrophysics Data System (ADS)

One-dimensional linear detector arrays have been used in the development of microscopes. Our confocal line scanning microscope electronics incorporate two printed circuit boards: control board and detector board. This architecture separates control electronics from detection electronics allowing us to minimize the footprint at microscope detector head. The Field Programmable Gate array (FPGA) on the control board generates timing and synchronization signals to three systems: detector board, frame grabber and galvanometric mirror scanner. The detector is kept away from its control electronics, and the clock and control signals are sent over a differential twisted-pair cable. These differential signals are translated to single ended signals and forwarded to the detector at the microscope detector head. The synchronization signals for the frame grabber are sent over a shielded cable. The control board also generates a saw tooth analog ramp to drive the galvanometric mirror scanner. The analog video output of the detector is fed into an operational amplifier where the white and the black levels are adjusted. Finally the analog video is send to the frame grabber via a shielded cable. FPGA-based electronics offer an inexpensive convenient means to control and synchronize simple line-scanning confocal microscopes.

Abeytunge, Sanjee; Toledo-Crow, Ricardo; Rajadhyaksha, Milind

2009-02-01

330

Spatial resolution of SCD's InSb 2D detector arrays  

Microsoft Academic Search

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 15mum. 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:

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

2007-01-01

331

Performances Of Arrays Of Ge:Ga Far-Infrared Detectors  

NASA Technical Reports Server (NTRS)

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

Mccreight, C.; Farhoomand, J.

1992-01-01

332

The acceptance of surface detector arrays for high energy cosmological muon neutrinos  

NASA Astrophysics Data System (ADS)

In order to search for ultra-high energy cosmological earth-skimming muon neutrinos by the surface detector array (SD) similar to one of the Pierre Auger Observatory (PAO), we propose to use the transition electromagnetic radiation at the medium interface induced by earth-skimming muons for triggering a few of aligned neighboring Cherenkov SD stations. Simulations of the acceptance of a modeling SD array have been done to estimate the detection probability of earth-skimming muon neutrinos.

Van Thuan, Vo; Van Khanh, Hoang

2011-03-01

333

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

334

X-RAY FOCUSING CRYSTAL VON HAMOS SPECTROMETER WITH A CCD LINEAR ARRAY AS A DETECTOR  

Microsoft Academic Search

An x-ray focusing crystal von Hamos spectrometer was developed using mica and graphite cylindrical crystals (radius of curvature R=20 mm) with a CCD linear array detector. The commercial CCD (Toshiba model TCD 1304AP) used for x-ray detection has 3724 pixels (8 ?m width and 200 ?m height) giving a total length of ~30 mm. The CCD detector was absolutely calibrated

A. Shevelko; A. Antonov; I. Grigorieva; O. Yakushev; L. Knight; Q. Wang

2002-01-01

335

XRF spectrometers based on monolithic arrays of silicon drift detectors: elemental mapping analyses and advanced detector structures  

Microsoft Academic Search

We present a novel X-ray Fluorescence (XRF) spectrometer based on a ring-shaped monolithic array of silicon drift detectors (SDDs) with a hole laser-cut in the center and we show some examples of its application in elemental mapping analyzes. The X-ray excitation beam, focused by a polycapillary X-ray lens in a small and intense spot, reaches the sample going through the

A. Longoni; C. Fiorini; C. Guazzoni; S. Buzzetti; M. Bellini; L. Struder; P. Lechner; A. Bjeoumikhov; J. Kemmer

2006-01-01

336

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

NASA Technical Reports Server (NTRS)

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

Timothy, J. G.

1983-01-01

337

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

NASA Technical Reports Server (NTRS)

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

Kasle, David B. (inventor)

1995-01-01

338

Instrumentation and performance of the water Cherenkov detector array at Sierra La Negra site  

NASA Astrophysics Data System (ADS)

We present results from the operation of the high mountain array of 4 water Cherenkov detectors located at 4550 m. a.s.l. located at Sierra Negra mountain (N 18 59.1, W 97 18.76 ) near of Puebla city in Mexico. The detectors consist of 4 light-tight cylindrical containers of 4 m2 cross section separated 25m. The vertices of the array form a triangle with one detector in the middle. The detector containers are filled with 5000 l of purified water and have a 5'' photomultiplier (EMI model 9030 A) facing down along the cylindrical axes. The acquisition electronics consists of scalers counting the number of particles every 5 ms, and an osciloscope used to fully record the traces of the four signals coming from the water Cherenkov detectors. The trigger signals correspond to photon candidate coming from a selected direction with an accuracy lower than one degree. Data and preliminary analysis are described corresponding to the last six months when operation of this detector array has been stable.

Salazar, H.; Alvarez, C.; Martinez, O.; et al.

339

Multi-residue determination of non-steroidal anti-inflammatory drug residues in animal serum and plasma by HPLC and photo-diode array detection.  

PubMed

The European Union regulated the use of non-steroidal anti-inflammatory drugs (NSAIDs) in animal production and set the official analytical controls to detect their residues in plasma, serum, and milk within the frame of national monitoring programs in each member state. In this work, a multi-residue reversed-phase high-performance liquid chromatography with diode array detector (DAD) method is described for the simultaneous determination of 13 NSAIDs in serum and plasma of farm animals. Chromatographic separation by a C12 stationary phase column with a linear gradient is able to resolve all the compounds considered: salicylic acid, ketoprofen, flurbiprofen, phenylbutazone and its metabolite (oxyphenbutazone), carprofen, ibuprofen, naproxen, niflumic acid, suxibutazone, diclofenac, mefenamic acid, and tolfenamic acid. These compounds are chosen as the most representative of the different NSAID chemical sub-classes. The DAD analysis allows the confirmation of all drugs on the basis of their own UV-vis spectrum, according to the requirements of the European Council Decision 2002/657/EC. Moreover, the method is in-house validated, evaluating mean recoveries, specificity, repeatability, and within-laboratory reproducibility as the performance parameters required by the Decision. The results of this study indicate the method is specific and repeatable, with the mean percentage recoveries of the drugs ranging between 72.5% and 104.5%. Only salicylic acid has poor recovery, with results ranging between 36.3% and 54.9%. PMID:17254366

Gallo, Pasquale; Fabbrocino, Serena; Vinci, Floriana; Fiori, Maurizio; Danese, Vincenzo; Nasi, Antonella; Serpe, Luigi

2006-01-01

340

Deterioration of Electrical and Spectroscopic Properties of a Detector Grade Silicon Photodiode Exposed to Short Range Proton, Lithium and Oxygen Ion Irradiation  

Microsoft Academic Search

The electrical properties and spectral response of a Hamamatsu S5821 silicon PIN photodiode were investigated in-situ during and after irradiation by 430 keV H+, 2.15 MeV Li2+, 4 MeV O3+ and 6.5 MeV O4+ ion beams focused to a sub-micrometer beam size. Ion species and their respective energies were selected to approximately have the same end range of 5 mum

Zeljko Pastuovic; Milko Jaksic; Gabor Kalinka; Mihaly Novak; Aliz Simon

2009-01-01

341

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

NASA Technical Reports Server (NTRS)

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

Timothy, J. G.

1976-01-01

342

Measurement of the Ultra-High Energy Cosmic Ray Spectrum by the Telescope Array Surface Detector  

NASA Astrophysics Data System (ADS)

The Telescope Array experiment is the largest cosmic ray observatory in the northern hemisphere. Telescope Array consists of an array of 507 scintillation counter surface detectors (TASD) augmented by three optical fluorescence telescope observatories. In analyzing the data collected by the TASD, a novel technique is employed which consists of generating a very detailed simulation that can be directly compared against actual observations. This enables a very careful analysis with a thoroughgoing understanding of the resolution constraints in the data. This method will be described and the most recent TASD measurement of the cosmic ray energy spectrum will be presented.

Stokes, Benjamin

2013-04-01

343

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

344

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

345

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

346

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

347

Ge\\/Si photodiodes with embedded arrays of Ge quantum dots forthe near infrared (1.3–1.5 µm) region  

Microsoft Academic Search

A method has been devised for MBE fabrication of p-i-n photodiodes for the spectral range of 1.3–1.5 m, based on multilayer Ge\\/Si heterostructures with Ge quantum dots (QDs) on\\u000a a Si substrate. The sheet density of QDs is 1.21012 cm?2, and their lateral size is ?8 nm. The lowest room-temperature dark current reported hitherto for Ge\\/Si photodetectors is\\u000a achieved (210?5

A. I. Yakimov; A. V. Dvurechenskii; A. I. Nikiforov; S. V. Chaikovskii; S. A. Tiis

2003-01-01

348

Development of a Low Noise Optoelectronic Integrated Readout with N-I A-SI:H Photodiode Array for Positron Emission Tomography  

NASA Astrophysics Data System (ADS)

Detection of scintillation light from LSO crystals used in Positron Emission Tomography is traditionally based on photo multipliers. The proposal is to develop a novel photo sensor, which is based on vertically integrating an hydrogenated amorphous silicon (a-Si:H) film on a pixel readout chip. The a-Si:H film is deposited with a n-i-p diode structure. Section 1 compares different circuit topologies, at the transistor level, in order to fulfill the noise requirement for the circuit. Quantum Efficiency results of a-Si:H photodiodes deposited on glass and on integrated circuits are reported in section 2.

Nardulli, Alessandro; Despeisse, M.; Dissertori, G.; Dunand, S.; Jarron, P.; Lustermann, W.; Moraes, D.; Schinzel, D.; Wyrsch, N.

2008-06-01

349

Measuring the ultra-high energy comic ray flux with the Telescope Array Middle Drum detector  

Microsoft Academic Search

The Telescope Array (TA) Experiment, located 200 kilometers southwest of Salt Lake City, Utah, is the largest Ultra-High Energy cosmic ray detector in the northern hemisphere. TA is a follow up to the High Resolution Fly's Eye (HiRes) and AGASA experiments, and seeks to gain insight into cosmic ray acceleration by measuring the flux of cosmic rays with energies over

Thomas Sonley

2009-01-01

350

High spin gamma-ray coincidence spectroscopy with large detector arrays.  

National Technical Information Service (NTIS)

In-beam (gamma)-ray spectroscopy has been used to study rapidly rotating nuclei in the rare-earth region. The experiments were performed using the high-resolution multi detector arrays ESSA30 and TESSA3 at the Nuclear Structure Facility, Daresbury Laborat...

M. H. Bergstroem

1992-01-01

351

An electrochemical detector array to study cell biology on the nanoscale  

Microsoft Academic Search

Nanobiotechnology is a field that utilizes the techniques of nano- and microfabrication to study biosystems or to use biological material and principles to build new devices. As an example we discuss the development of a nanofabricated electrochemical detector array that reveals the spatio-temporal dynamics of exocytosis in single chromaffin cells. In a quantal release event a single vesicle fuses with

Andrew F. Dias; Gregor Dernick; Vicente Valero; Ming G. Yong; Conrad D. James; Harold G. Craighead; Manfred Lindau

2002-01-01

352

Thin Film CdZnTe Detector Arrays for Digital Mammography.  

National Technical Information Service (NTIS)

The objective of this program was to develop large-area, flat-panel detectors for digital mammography using CdTe or CdZnTe deposited by metalorganic chemical vapor deposition (MOCVD) directly on thin-film transistor (TFT) active matrix arrays for image re...

N. M. Kalkhoran

2001-01-01

353

Analyzing the performance of a nanosatellite cluster-detector array receiver for laser communication  

Microsoft Academic Search

This work analyzes laser communication between a cluster of nanosatellites, which is a concentrated formation of small lightweight satellites and a ground station. The scenario under consideration is a cluster of nanosatellites communicating by means of a laser beam with a detector array receiver that is located on the earth's surface and equipped with a common optical system for all

Denis Bushuev; Debbie Kedar; Shlomi Arnon

2003-01-01

354

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

Microsoft Academic Search

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

Zhi Liu

2007-01-01

355

Status of LWIR HgCdTe infrared detector technology  

NASA Technical Reports Server (NTRS)

The performance requirements that today's advanced Long Wavelength Infrared (LWIR) focal plane arrays place on the HgCdTe photovoltaic detector array are summarized. The theoretical performance limits for intrinsic LWIR HgCdTe detectors are reviewed as functions of cutoff wavelength and operating temperature. The status of LWIR HgCdTe photovoltaic detectors is reviewed and compared to the focal plane array (FPA) requirements and to the theoretical limits. Emphasis is placed on recent data for two-layer HgCdTe PLE heterojunction photodiodes grown at Loral with cutoff wavelengths ranging between 10 and 19 microns at temperatures of 70 to 80 K. Development trends in LWIR HgCdTe detector technology are outlined, and conclusions are drawn about the ability for photovoltaic HgCdTe detector arrays to satisfy a wide variety of advanced FPA array applications.

Reine, M. B.

1990-01-01

356

Phytochemical and morphological characterization of hop (Humulus lupulus L.) cones over five developmental stages using high performance liquid chromatography coupled to time-of-flight mass spectrometry, ultrahigh performance liquid chromatography photodiode array detection, and light microscopy techniques.  

PubMed

Hop (Humulus lupulus L.) inflorescences, commonly known as "hop cones", are prized for their terpenophenolic contents, used in beer production and, more recently, in biomedical applications. In this study we investigated morphological and phytochemical characteristics of hop cones over five developmental stages, using liquid chromatography coupled to time-of-flight mass spectrometry (LC-TOF-MS), and ultrahigh performance liquid chromatography photodiode array detection (UHPLC-PDA) methods to quantitate 21 polyphenolics and seven terpenophenolics. Additionally, we used light microscopy to correlate phytochemical quantities with changes in the morphology of the cones. Significant increases in terpenophenolics, concomitant with glandular trichome development and associated gross morphological changes, were mapped over development to fluctuations in contents of polyphenolic constituents and their metabolic precursor compounds. The methods reported here can be used for targeted metabolic profiling of flavonoids, phenolic acids, and terpenophenolics in hops, and are applicable to quantitation in other crops. PMID:21456557

Kavalier, Adam R; Litt, Amy; Ma, Chunhui; Pitra, Nicholi J; Coles, Mark C; Kennelly, Edward J; Matthews, Paul D

2011-05-11

357

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

2011-09-15

358

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

359

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

NASA Astrophysics Data System (ADS)

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

Franco, L.; Gómez, F.; Badano, A.

2008-11-01

360

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

361

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

362

Multiple detector focal plane array ultraviolet spectrometer for the AMPS laboratory  

NASA Technical Reports Server (NTRS)

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

Feldman, P. D.

1975-01-01

363

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

NASA Astrophysics Data System (ADS)

We have performed the study on the dependence of laser beam induced current (LBIC) spectra on the temperature for the vacancy-doped molecular beam epitaxy grown Hg1-xCdxTe (x = 0.31) photodiodes by both experiment and numerical simulations. It is found that the measured LBIC signal has different distributions for different temperature extents. The LBIC profile tends to be more asymmetric with increasing temperature below 170 K. But the LBIC profile becomes more symmetric with increasing temperature above 170 K. Based on a localized leakage model, it is indicated that the localized junction leakage can lead to asymmetric LBIC signal, in good agreement with the experimental data. The reason is that the trap-assisted tunneling current is the dominant leakage current at the cryogenic temperature below 170 K while the diffusion current component becomes dominant above the temperature of 170 K. The results are helpful for us to better clarify the mechanism of the dependence of LBIC spectra on temperature for the applications of HgCdTe infrared photodiodes.

Feng, A. L.; Li, G.; He, G.; Sun, Z. Q.; Hu, W. D.; Chen, X. S.; Yin, F.; Zhang, B.; Lu, W.

2013-11-01

364

High-resolution ultrasonic imaging using an etalon detector array  

PubMed Central

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

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

2008-01-01

365

Twelve-channel individually addressable InGaAs\\/InP p-i-n photodiode and InGaAsP\\/InP LED arrays in a compact package  

Microsoft Academic Search

We report on monolithically integrated 1 × 12 arrays of In0.53Ga0.47As p-i-n detectors and InGaAsP LED's for use in long-wavelength optical communication system applications. The detectors are sensitive in the wavelength region of0.95-1.65 mum, and the LED's emit at 1.30 ?m. The devices utilize Si V-block fiber array connectors with one end polished at a 45° angle with respect to

YUSUKE OTA; RICHARD C. MILLER; STEPHEN R. FORREST; DANIEL R. KAPLAN; CHARLES W. SEABURY; ROBERT B. HUNTINGTON; JULIA G. JOHNSON; JOSEPH R. POTOPOWICZ

1987-01-01

366

Photon detection with cooled avalanche photodiodes  

NASA Technical Reports Server (NTRS)

Commercial avalanche photodiodes have been operated as single-photon detectors at an optimum operating temperature and bias voltage. These detectors were found to be 1.5-3 times more sensitive than presently available photomultiplier tubes (PMTs). Both single-photon detection probability and detector noise increase with bias voltage; detection probabilities greater than twice that of a PMT were obtained with detector noise levels below 100 counts per second. Higher probabilities were measured at higher noise levels. The sources of noise and their dependence on temperature and bias voltage are discussed.

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

1987-01-01

367

Cooled avalanche photodiode used for photon detection  

NASA Technical Reports Server (NTRS)

Commercial avalanche photodiodes have been operated as single-photon detectors at an optimum operating temperature and bias voltage. These detectors were found to be 1.5 to 3 times more sensitive than presently-available photomultiplier tubes (PPMTs). Both single-photon detection probability and detector noise increase with bias voltage; detection probabilities greater than 25 percent were obtained with detector noise levels comparable to the noise of a PMT; higher probabilities were measured at higher noise levels. The sources of noise and their dependence on temperature and bias voltage are discussed.

Robinson, Deborah L.; Metscher, Brian D.

1987-01-01

368

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

369

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

370

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

371

Range performance modeling for staring focal plane array infrared detectors  

NASA Astrophysics Data System (ADS)

The generally accepted models for imaging and range performance modeling of thermal imagers have not been able to properly model under-sampled systems, i.e. staring focal plane arrays (FPAs). The ruling STANAGs 4349 and 4350 on measurement and modeling of Minimum Resolvable Temperature Difference (MRTD), by definition only deal with properly sampled systems and thus cannot address performance beyond the Nyquist frequency. This includes the FLIR92 model which is based on the models defined in STANAG 4350. Range performance modeling, defined through STANAG 4347, is based on MRTD and thus likewise limits performance to below Nyquist frequencies. Practical experience has long shown that this limitation is not valid and development of new modeling techniques to address these problems has been performed e.g. in Germany, the TRM3 model, and in the US, with the NVTherm model. TRM3 addresses the under-sampled systems by introducing a concept of Minimum Temperature Difference Perceived (MTDP) which replaces MRTD for frequencies beyond Nyquist. NVTherm instead introduces a modified MRTD function through the concept of MTF squeeze. Typically, range performance predictions from NVTherm will increase ranges by some 15% over Nyquist resolution based predictions, and TRM3 based predictions exceed Nyquist ranges by up to 30%. A study is done to compare modeling results from these two models with laboratory measurements (MRTD) on QWIP long wave staring FPA based thermal imagers and finally relate these to empirical data from range performance field trials against actual targets.

Dahlberg, Anders G. M.; Holmgren, Olof

2005-05-01

372

New detector array - the HRIBF Modular Total Absorption Spectrometer  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

373

Development of the superorruba detector array and the measurement of single particle states in 81Ge  

NASA Astrophysics Data System (ADS)

The study of nuclei far from stability elucidates the evolution of nuclear shell structure, and also affects estimates of heavy element nucleosynthesis in supernova explosions. Measurement of transfer reactions in inverse kinematics with radioactive ion beams is a powerful technique for these types of studies. Rare isotope beams often have relatively low intensities, and this places difficult requirements on the detection systems for reaction products. The detectors must provide large solid angle coverage in the laboratory along with good position and energy resolution. The Super ORRUBA detector array has been developed for such measurements and is comprised of 18 double-sided, nonresistive silicon strip detectors. This configuration features low thresholds and improved resolution over detectors employing charge division. As a first implementation of this system, the 80Ge(d,p)81Ge neutron transfer reaction in inverse kinematics was measured at HRIBF at ORNL, to determine the properties of levels in 81Ge.

Ahn, S.; Adekola, A. S.; Bardayan, D. W.; Blackmon, J. C.; Chae, K. Y.; Chipps, K. A.; Cizewski, J. A.; Elson, J.; Hardy, S.; Howard, M. E.; Jones, K. L.; Kozub, R. L.; Manning, B.; Matos, M.; Nesaraja, C. D.; O'Malley, P. D.; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Rasco, B. C.; Smith, M. S.; Sobotka, L. G.; Spassova, I.

2013-04-01

374

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

375

Trigger electronics of the new Fluorescence Detectors of the Telescope Array Experiment  

NASA Astrophysics Data System (ADS)

The Telescope Array Project is an experiment designed to observe Ultra High Energy Cosmic Rays via a “hybrid” detection technique utilizing both fluorescence light detectors (FDs) and scintillator surface particle detectors (SDs). We have installed three FD stations and 507 SDs in the Utah desert, and initiated observations from March 2008. The northern FD station reuses 14 telescopes from the High Resolution Fly's Eye, HiRes-I station. Each of the two southern FD stations contains 12 new telescopes utilizing new FADC electronics. Each telescope is instrumented with a camera composed of 256 PMTs. Since the detectors are composed of many PMTs and each PMT detects fluorescence photons together with the vast amount of night sky background, a sophisticated triggering system is required. In this paper, we describe the trigger electronics of these new FD stations. We also discuss performance of the FDs with this triggering system, in terms of efficiencies and apertures for various detector configurations.

Tameda, Yuichiro; Taketa, Akimichi; Smith, Jeremy D.; Tanaka, Manobu; Fukushima, Masaki; Jui, Charles C. H.; Kadota, Ken'Ichi; Kakimoto, Fumio; Matsuda, Takeshi; Matthews, John N.; Ogio, Shoichi; Sagawa, Hiroyuki; Sakurai, Nobuyuki; Shibata, Tatsunobu; Takeda, Masahiro; Thomas, Stanton B.; Tokuno, Hisao; Tsunesada, Yoshiki; Udo, Shigeharu

2009-10-01

376

Integration of PMCC detector in seismic operational automatic processing chain. Validation on MMAI array.  

NASA Astrophysics Data System (ADS)

The PMCC method (Progressive Multi-Channels Correlation; Cansi, 1995) has been applied to the Mount Meiron array (MMAI station code) with the perspective to improve data processing such as detection and categorization. PMCC algorithm is based on a study of the cross-correlation functions between each stations of the array, which leads to a consistent set of time-delays when a seismic phase is present. The set of time-delays allows calculation of horizontal velocity and azimuth of arrival wavefront. We show that PMCC detector with a configuration designed for P-wave characteristics allows improving significantly the detection threshold of MMAI array compared to standard seismic-to-noise ratio detectors. |In addition a comparison of pmcc performance for several International Monitoring System (IMS) to the current array detector used by the International Data Center (IDC) is given. Moreover, the analysis of P-wave parameters gives a first insight to the categorization issue. Statistic approach applied to PMCC results allow identification of seismic sequence and differentiation with independent seismic or noise detections. Categorization is essential to reduce drastically the number of detections, in order to integer PMCC results in operational automatic detection processing chain. We propose also a python routine for uploading pmcc detections into database for storage compatible with CTBTO environment.

Cano, Y.; Ben-Horin, Y.

2012-04-01

377

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

PubMed

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

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

2013-04-01

378

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

379

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

380

Photodiode design study  

Microsoft Academic Search

The purpose of this work was to apply the analytical method developed for single junction and multijunction solar cells, Contract No. F33615-76-C-1283, to photodiodes and avalanche photodiodes. It was anticipated that this analytical method will advance the state-of-the-art because of the following: (1) the analysis considers the total photodetector multilayer structure rather than just the depleted region; (2) a model

M. F. Lamorte

1977-01-01

381

Application of far-infrared, integrated detector arrays to chord-averaged plasma measurements (invited)  

SciTech Connect

The recent development of linear, monolithic microbolometer detector arrays for the far infrared has led to the construction of active imaging diagnostics for tokamak plasmas. Detector arrays have an advantage over discrete detectors in that the cost per detector is significantly reduced since many detectors are fabricated simultaneously. Also, the plasma can be probed with a higher spatial resolution than conventional discrete-beam systems because of the higher channel density. Another advantage is provided by the increased channel number which is important to chord-averaged measurements since it allows an increase in the accuracy of the calculation of Abel inversions of the measured line density profile which are used to reconstruct the actual electron density distribution. The usefulness of this technique has been demonstrated on the UCLA Microtor tokamak (a = 11 cm, B/sub T/ = 20 kG, I = 70 kA, n/sub e/ = 5 x 10/sup 13/ cm/sup -3/) in which a 20-channel heterodyned interferometer at wavelengths of 800 and 1000 ..mu..m has been used to study the behavior of the plasma profile. Line density profiles during the startup phase of the tokamak discharge have been obtained, as well as sawtooth fluctuation profiles. The imaging technique can also be applied to Faraday rotation measurements of the poloidal magnetic field in the tokamak. A 20-channel polarimeter has been developed that operates simultaneously with the multichannel interferometer.

Young, P.E.

1985-05-01

382

Synchrotron x-ray photoconductor detector arrays made on MBE grown CdTe  

SciTech Connect

We have been fabricating x-ray photoconductor linear array detectors using molecular beam epitaxially (MBE) grown (111)B undoped CdTe layers on (100) Si substrates. A novel technique was developed to remove the Si and to mount the fragile MBE grown CdTe layers onto insulating ceramic substrates. 256 channel linear photoconductor array devices were fabricated on the resulting CdTe layers. The resistivity of MBE (111)B CdTe was high (> 10{sup 8} {Omega}cm) enough to utilize the material for low energy (8 to 25 keV) x-ray detectors. The stability of the detectors are satisfactory, and they were tested at room temperature routinely for over a year. The performance of the photoconductor was greatly improved when the detector was cooled to 230K. Due to its reduced dark current at low temperatures, the dynamic range of the detector response increased to nearly four decades at 230K. 29 refs., 8 figs.

Yoo, S.S.; Montano, P.A. [Univ. of Illinois, Chicago, IL (United States)]|[Argonne National Lab., IL (United States); Rodricks, B. [Argonne National Lab., IL (United States); Sivananthan, S.; Faurie, J.P. [Univ. of Illinois, Chicago, IL (United States)

1996-08-01

383

Very fast integrated optoelectronic logic for parallel computation using photodiode gates  

NASA Astrophysics Data System (ADS)

A new configuration of an integrated optoelectronic logic unit using GaAs photodiode gates is proposed. Implementation of AND and EOR logic units are performed monolithically using GaAs/AlGaAs multilayer structures. Discussions are made on the realization of the full adder by means of optical feedback between the photodiode logic array and the surface emitting diode laser array.

Kamiyama, Hiroyuki; Shouno, Atsuo; Kamiya, Takeshi; Umemoto, Yasunari

1990-07-01

384

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

385

Calibration and monitoring of the air fluorescence detector for the Telescope Array experiment  

NASA Astrophysics Data System (ADS)

The air fluorescence detectors (FDs) of the Telescope Array (TA) experiment have been constructed in a dessert of Utah, USA. We can measure the longitudinal developments of EASs directly with the FDs by detecting air fluorescence lights and determine the primary energies of ultra-high energy cosmic rays. In order for accurate observation and measurements of EASs, elaborate detector calibrations and monitoring systems are required. We will present the result of calibration and monitoring systems for the reflectance and curvature radius of segment mirrors, the characteristics of PMT (absolute gain, linearity, temperature dependence of gain), and the uniformity of the camera surface, etc.

Tokuno, H.; Azuma, R.; Fukushima, M.; et al.

386

Evaluation of a far infrared Ge:Ga multiplexed detector array  

Microsoft Academic Search

The performance of a multielement Ge:Ga linear array under low-background conditions is investigated. On-focal plane switching is accomplished by MOSFET switches and the integrated charge is made available through MOSFET source followers. The tests were conducted at 106 microns and the radiation on the detectors was confined to a spectral window 1.25 microns wide using a stack of cold filters.

Jam Farhoomand; Craig McCreight

1990-01-01

387

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

Microsoft Academic Search

The performance of two multi-element, multiplexed Ge:Ga linear arrays under low-background conditions was investigated. The on-focal switching is accomplished by MOSFET switches, and the integrated charge is made available through MOSFET source followers. The tests were conducted at 106 microns, and the radiation on the detectors was confined to a spectral window 1.25 microns wide using a stack of cold

Jam Farhoomand; Craig McCreight

1990-01-01

388

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

Microsoft Academic Search

The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 mum cutoff (lambdaco =5 mum) 2048×2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T ~ 37 K. In this article, we provide a brief introduction to NIRSpec,

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

2007-01-01

389

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

390

The HAWAII Infrared Detector Arrays: testing and astronomical characterization of prototype and science-grade devices  

Microsoft Academic Search

Two generations of prototypes of a HgCdTe infrared detector array with 1024 × 1024 pixels developed by the Rockwell International Science Center have been tested in the new Quick Infrared Camera (QUIRC) and an upgraded version of KSPEC a cross-dispersed near-infrared spectrograph, on the University of Hawaii 2.2 m telescope.The HAWAII (HgCdTe Astronomical Wide Area Infrared Imager) prototype devices achieved

K.-W. Hodapp; J. L. Hora; D. N. B. Hall; L. L. Cowie; M. Metzger; E. Irwin; K. Vural; L. J. Kozlowski; S. A. Cabelli; C. Y. Chen; D. E. Cooper; G. L. Bostrup; R. B. Bailey; W. E. Kleinhans

1996-01-01

391

58 X 62 Si:As IBC detector arrays on PMOS multiplexers for astronomy  

Microsoft Academic Search

Four 58 X 62-element Si:As impurity-band-conduction (IBC) detector arrays produced by the Hughes Technology Center were tested to evaluate their usefulness for space- and ground- based astronomical observations. PMOS circuitry was used in the multiplexers to improve low-temperature noise performance. Laboratory tests at background levels simulating those expected on space-based observing platforms were combined with ground-based telescope IR observations. The

Mark E. McKelvey; Robert E. McMurray; Craig R. McCreight; Thomas L. Roellig; Robert Cooper; Lunming Yuen; Lynne K. Deutsch

1993-01-01

392

The EAS-TOP array at Gran Sasso: results of the electromagnetic detector  

NASA Astrophysics Data System (ADS)

The detector of the e.m. component of Extensive Air Showers of the EAS-TOP array at Gran Sasso has been in operation for part of 1988 and 1989. We present the results obtained at primary energy E? ~ 150 TeV in the study of the candidate sources observable in the northern emisphere. The observations of Cygnus X-3 during the radio burst of June '89 are discussed.

Aglietta, M.; Alessandro, B.; Badino, G.; Bergamasco, L.; Castagnoli, C.; Castellina, A.; Cini, G.; D'Ettorre Piazzoli, B.; Fulgione, W.; Galeotti, P.; Ghia, P. L.; Mannocchi, G.; Morello, C.; Navarra, G.; Periale, L.; Picchi, P.; Riccati, L.; Saavedra, O.; Trinchero, G. C.; Vallania, P.; Vernetto, S.

1990-08-01

393

Photo sensor array technology development  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

394

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

395

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

NASA Astrophysics Data System (ADS)

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

Kwon, Sun Il; Lee, Jae Sung

2014-10-01

396

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

397

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

SciTech Connect

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

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

2009-08-15

398

Detector arrays for photometric measurements at soft X-ray, ultraviolet and visible wavelengths  

NASA Technical Reports Server (NTRS)

The construction and modes of operation of the Multi-Anode Microchannel Array (MAMA) detectors are described, and the designs of spectrometers utilizing them are outlined. MAMA consists of a curved microchannel array plate, an opaque photocathode (peak quantum efficiency of 19% at 1216 A), and a multi-anode (either discrete- or coincidence-anode) readout array. Designed for use in instruments on spaceborne telescopes, MAMA can be operated in a windowless configuration in extreme-ultraviolet and soft X-ray wavelengths, or in a sealed configuration at UV and visible wavelengths. Advantages of MAMA include low applied potential (less than 3.0 kV), high gain (greater than 10 to the 6th electrons/pulse), low sensitivity to high-energy charged particles, and immunity to external magnetic fields of less than 500 Gauss

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

1979-01-01

399

Design and Fabrication of Microwave Kinetic Inductance Detectors using NbN Symmetric Spiral Resonator Array  

NASA Astrophysics Data System (ADS)

We designed and fabricated a microwave kinetic inductance detector (MKID) using a niobium nitride (NbN) symmetric spiral resonator array. Previously we revealed that a rewound spiral structure works as not only a high-Q half-wavelength resonator but also as a broadband terahertz antenna. We conducted simulations for a 9 resonator array assuming NbN as the superconducting material and sapphire as the dielectric substrate, and obtained a maximum attenuation of over 30 dB and unloaded quality factors of over 2×105 for frequencies between 4.4 and 4.9 GHz. We fabricated the 9 resonator array MKID using NbN thin film deposited on an m-sapphire substrate by using dc magnetron sputtering. We observed half-wavelength resonances of around 4.5 GHz at 4 K. We measured the optical response of the MKID. The frequency shift was 0.5 MHz when illuminated with 650 nm photons.

Hayashi, K.; Saito, A.; Ogawa, Y.; Murata, M.; Sawada, T.; Nakajima, K.; Yamada, H.; Ariyoshi, S.; Taino, T.; Tanoue, H.; Otani, C.; Ohshima, S.

2014-05-01

400

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

401

Development of Ta-based STJ X-ray Detector Arrays for Synchrotron Science  

NASA Astrophysics Data System (ADS)

We are developing a cryogen-free Ta-based superconducting tunnel junction (STJ) detector for soft X-ray spectroscopy at synchrotrons. With an energy resolution 10 times higher than conventional solid-state X-ray detectors and count-rate capabilities above 5 kHz/pixel, STJ detectors offer potentially increased sensitivity for fluorescence-yield X-ray absorption spectroscopy (FY-XAS). We have developed 36-pixel arrays of 208 × 208 \\upmu m Ta STJs with an energy resolution of ˜ 9 eV FWHM at the 525 eV oxygen K line. Compared to earlier Nb-based STJs, Ta-STJs offer improved energy resolution and absorption efficiency and extend the operating range to several keV. Here we describe the integration of the 36-pixel arrays into a cryogen-free, user-friendly X-ray spectrometer. A computer-controlled adiabatic demagnetization refrigerator coupled to a two-stage pulse tube refrigerator allows operation below 100 mK. The detector chip is located at the end of a 42 cm shielded snout for insertion into the analysis chamber. The system is currently being commissioned at the Advanced Light Source synchrotron.

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

2014-05-01

402

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

SciTech Connect

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

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

1997-03-01

403

Development of Ta-based STJ X-ray Detector Arrays for Synchrotron Science  

NASA Astrophysics Data System (ADS)

We are developing a cryogen-free Ta-based superconducting tunnel junction (STJ) detector for soft X-ray spectroscopy at synchrotrons. With an energy resolution 10 times higher than conventional solid-state X-ray detectors and count-rate capabilities above 5 kHz/pixel, STJ detectors offer potentially increased sensitivity for fluorescence-yield X-ray absorption spectroscopy (FY-XAS). We have developed 36-pixel arrays of 208 208 m Ta STJs with an energy resolution of 9 eV FWHM at the 525 eV oxygen K line. Compared to earlier Nb-based STJs, Ta-STJs offer improved energy resolution and absorption efficiency and extend the operating range to several keV. Here we describe the integration of the 36-pixel arrays into a cryogen-free, user-friendly X-ray spectrometer. A computer-controlled adiabatic demagnetization refrigerator coupled to a two-stage pulse tube refrigerator allows operation below 100 mK. The detector chip is located at the end of a 42 cm shielded snout for insertion into the analysis chamber. The system is currently being commissioned at the Advanced Light Source synchrotron.

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

2014-08-01

404

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

PubMed

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. PMID:23082277

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

2012-10-01

405

Large-scale numerical simulation of reduced-pitch HgCdTe infrared detector arrays  

NASA Astrophysics Data System (ADS)

Numerical simulations play an important role in the development of large-format infrared detector array tech- nologies, especially when considering devices whose sizes are comparable to the wavelength of the radiation they are detecting. Computational models can be used to predict the optical and electrical response of such devices and evaluate designs prior to fabrication. We have developed a simulation framework which solves Maxwell's equations to determine the electromagnetic properties of a detector and subsequently uses a drift-diffusion ap- proach to asses the electrical response. We apply these techniques to gauge the effects of cathode placement on the inter- and intra-pixel attributes of compositionally graded and constant Hg1-xCdxTe mid-wavelength infrared detectors. In particular, the quantum efficiency, nearest-neighbor crosstalk, and modulation transfer function are evaluated for several device architectures.

Pinkie, Benjamin; Bellotti, Enrico

2013-06-01

406

a Cosmic Ray Detector Array for Schools in the Cambridge Region  

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

407

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, Ch. O.; Bocage, F.; Bougault, R.; Brou, R.; Buchet, Ph.; 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.; Le Fèvre, A.; Lefort, T.; Legrain, R.; Le Neindre, N.; 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

408

Numerical Simulation of the Modulation Transfer Function in HgCdTe Detector Arrays  

NASA Astrophysics Data System (ADS)

In this work, we develop a method for simulating the modulation transfer function (MTF) of infrared detector arrays, which is based on numerical evaluation of the detector physics. The finite-difference time-domain and finite element methods are used to solve the electromagnetic and electrical equations for the device, respectively. We show how the total MTF can be deconvolved to examine the effects of specific physical processes. We introduce the MTF area difference and use it to quantify the effectiveness of several crosstalk mitigation techniques in improving the system MTF. We then apply our simulation methods to two-thirds generation mercury cadmium telluride (HgCdTe) detector architectures. The methodology is general, can be implemented with commercially available software, has experimentally realizable analogs, and is extendable to other material systems and device designs.

Pinkie, Benjamin; Bellotti, Enrico

2014-04-01

409

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

410

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

PubMed

This study described the performance of an array of high-purity Germanium detectors, designed with two different end cap materials-steel and carbon fibre. The advantages and disadvantages of using this detector type in the estimation of the minimum detectable activity (MDA) for different energy peaks of isotope (152)Eu were illustrated. A Monte Carlo model was developed to study the detection efficiency for the detector array. A voxelised Lawrence Livermore torso phantom, equipped with lung, chest plates and overlay plates, was used to mimic a typical lung counting protocol with the array of detectors. The lung of the phantom simulated the volumetric source organ. A significantly low MDA was estimated for energy peaks at 40 keV and at a chest wall thickness of 6.64 cm. PMID:22355171

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

2012-08-01

411

A micro GC detector array based on chemiresistors employing various surface functionalized monolayer-protected gold nanoparticles.  

PubMed

Aspects of the design, fabrication, and characterization of a chemiresistor type of microdetector for use in conjunction with gas chromatograph are described. The detector was manufactured on silicon chips using microelectromechanical systems (MEMS) technology. Detection was based on measuring changes in resistance across a film comprised of monolayer-protected gold nanoclusters (MPCs). When chromatographic separated molecules entered the detector cell, the MPC film absorbed vapor and undergoes swelling, then the resistance changes accordingly. Thiolates were used as ligand shells to encapsulate the nano-gold core and to manipulate the selectivity of the detector array. The dimensions of the ?-detector array were 14(L)×3.9(W)×1.2(H)mm. Mixtures of eight volatile organic compounds with different functional groups and volatility were tested to characterize the selectivity of the ?-detector array. The detector responses were rapid, reversible, and linear for all of the tested compounds. The detection limits ranged from 2 to 111ng, and were related to both the compound volatility and the selectivity of the surface ligands on the gold nanoparticles. Design and operation parameters such as flow rate, detector temperature, and width of the micro-fluidic channel were investigated. Reduction of the detector temperature resulted in improved sensitivity due to increased absorption. When a wider flow channel was used, the signal-to-noise ratio was improved due to the larger sensing area. The extremely low power consumption and small size makes this ?-detector array potentially useful for the development of integrated ?-GC. PMID:22265482

Jian, Rih-Sheng; Huang, Rui-Xuan; Lu, Chia-Jung

2012-01-15

412

Low-flux measurements with Cornell's LCLS integrating pixel array detector  

NASA Astrophysics Data System (ADS)

Next generation light sources are revolutionizing x-ray science by delivering ultra-intense, hard x-ray pulses many orders of magnitude brighter and shorter in duration than previously achievable. Maximizing the scientific potential of these light sources requires the development of suitable detectors. Experiments such as coherent x-ray imaging of single particles require detectors that can record extremely high instantaneous flux rates produced by femtosecond x-ray pulses (i.e. thousands of photons incident on a single pixel of an area detector in a few femtoseconds) while also being able to accurately distinguish single photon events so that many thousands of frames of data can be used to reconstruct extremely low flux information (e.g. less than 1/1000 photons per pixel per frame). This paper presents data from an integrating pixel array detector (PAD) possessing the ability to record high- and low-flux x-ray data at an X-ray Free Electron Laser (XFEL). Methods are presented to process extremely low-flux data (less than 1/10000 8-keV x-rays per pixel per frame) to accurately recover diffraction patterns from thousands of frames. The data were collected using a detector developed by Cornell for the Linac Coherent Light Source (LCLS) at SLAC National Lab. A copy of this detector was delivered to SLAC in the middle of 2008. The ASIC developed for this detector was used by SLAC as the basis for the CS-PAD (Cornell SLAC-PAD) being used on the Coherent X-ray Imaging beamline at the LCLS. These methods extend beyond XFEL applications because they allow for the suppression of dark accumulation noise which typically limits the low-flux capability of integrating detectors on conventional x-ray sources.

Philipp, Hugh T.; Tate, Mark W.; Gruner, Sol M.

2011-11-01

413

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

414

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

NASA Astrophysics Data System (ADS)

We have designed and developed from the discrete component level a high resolution dynamic x-ray detector to be used for fluoroscopic and angiographic medical imaging. The heart of the detector is a 1024 ×1024 pixel electron multiplying charge coupled device (EMCCD) with a pixel size of 13 × 13 ?m2 (Model CCD201-20, e2v Technologies, Inc.), bonded to a fiber optic plate (FOP), and optically coupled to a 350 ?m thick micro-columnar CsI(TI) scintillator via a fiber optic taper (FOT). Our aim is to design an array of these detectors that could be extended to any arbitrary X × Y size in two dimensions to provide a larger field of view (FOV). A physical configuration for a 3×3 array is presented that includes two major sub-systems. First is an optical front end that includes (i) a phosphor to convert the x-ray photons into light photons, and (ii) a fused array of FOTs that focuses light photons from the phosphor onto an array of EMCCD's optically coupled using FOPs. Second is an electronic front end that includes (i) an FPGA board used for generating clocks and for data acquisition (ii) driver boards to drive and digitize the analog output from the EMCCDs, (iii) a power board, and (iv) headboards to hold the EMCCD's while they are connected to their respective driver board using flex cables. This configuration provides a larger FOV as well as region-of-interest (ROI) high-resolution imaging as required by modern neurovascular procedures.

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

2012-02-01

415

Avalanche photodiodes for electromagnetic calorimeters  

NASA Astrophysics Data System (ADS)

Hamamatsu S8148 silicon avalanche photodiode (APD) working in proportional mode has been chosen as readout device for the PbWO 4 crystals in the barrel of the CMS electromagnetic calorimeter (ECAL). High hadron fluences strongly affect the main parameters of both the scintillation crystals and the silicon detectors. In this work, we offer a new zinc sulfide-silicon (ZnS-Si) isotype heterojunction APD structure that is able to operate in high-radiation levels. A Monte Carlo simulation code has been performed in order to compare the Hamamatsu S8148 and the ZnS-Si APD structures for the photons emitting from PbWO 4 crystal during 10 years of CMS operation. Based on this work, the performance of these two APD structures has been investigated.

Pilicer, Ercan; Kocak, Fatma; Tapan, Ilhan; Ahmetoglu (Afrailov), Muhitdin

2007-03-01

416

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

417

Multi-Parameter High-Resolution Spatial Maps of a CdZnTe Radiation Detector Array.  

National Technical Information Service (NTIS)

Resistivity results from a 48x48 pixelated CdZnTe (CZT) radiation detector array are presented alongside X-ray topography and detector mapping with a collimated gamma-ray beam. By using a variety of measurements performed on the same sample and registerin...

1998-01-01

418

Hybrid UV Imager Containing Face-Up AlGaN/GaN Photodiodes  

NASA Technical Reports Server (NTRS)

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

Zheng, Xinyu; Pain, Bedabrata

2005-01-01

419

Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging  

PubMed Central

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

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

2009-01-01