Dr. Kanai S. Shah Profile

Dr. Kanai S. Shah

Deceased at Radiation Monitoring Devices Inc

SPIE Involvement:

Author

Publications (64)

Proceedings Article | 4 October 2022 Presentation + Paper

Thermal neutron detection with lithium-based semiconductors

Alireza Kargar, Huicong Hong, Joshua Tower, Paul Guggenheim, Eric Qian, Conner Brown, Mathew Breen, James Christian, Kanai Shah, Eric Lukosi, Robert Golduber, Jake Gallagher, Amine Benkechkache, Mercouri Kanatzidis, Michael Squillante

Proceedings Volume 12241, 1224108 (2022) https://doi.org/10.1117/12.2632318

KEYWORDS: Sensors, Crystals, Lithium, Semiconductors, Transmittance, Gold, Gamma radiation, Selenium, Electrons, Semiconducting wafers

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Proceedings Article | 4 October 2022 Presentation + Paper

Improved performance and longevity of large volume thallium bromide devices

H. Kim, L. Cirignano, J. F. Christian, A. Kargar, Y. Ogorodnik, S. Kim, M. Breen, M. R. Squillante, K. Shah

Proceedings Volume 12241, 1224106 (2022) https://doi.org/10.1117/12.2635925

KEYWORDS: Sensors, Cesium, Thallium, Semiconductors, Gamma radiation, Spectroscopy, Signal detection, Sensor performance, Amplifiers, Signal generators

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Proceedings Article | 3 October 2022 Presentation

Performance characterizations of position-sensitive virtual Frisch-grid TlBr detectors (Conference Presentation)

Aleksey Bolotnikov, Conner Brown, Gabriella Carini, James Christian, Leonard Cirignano, Connie-Rose Deane, Alfred Dellapenna, Grzegorz Deptuch, Jack Fried, Sven Herrmann, Hadong Kim, Giovanni Pinaroli, Alireza Kargar, Martin Koslowsky, Piotr Maj, Victor Manthena, Alexander Miller, Sandeep Miriala, Eric Raguzina, Kanai Shah, Michael Squillante, Martin Smith, Andrew Valente, Evan Weststrate

Proceedings Volume PC12241, PC122410D (2022) https://doi.org/10.1117/12.2635899

KEYWORDS: Sensors, Crystals, Semiconductors, Semiconductor materials, Ions, Gamma radiation, Electric field sensors

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Proceedings Article | 9 September 2019 Presentation

Cathode waveform analysis of TlBr semiconductor detectors (Conference Presentation)

Stephen Payne, Erik Swanberg, Sean O'Neal, Paul Bennett, Leonard Cirignano, Kanai Shah, Zhong He

Proceedings Volume 11114, 111140M (2019) https://doi.org/10.1117/12.2530334

KEYWORDS: Semiconductors, Sensors, Electrodes, Gamma radiation, Electron transport, Crystals

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Proceedings Article | 13 September 2018 Presentation + Paper

CVD diamond for beta particle detection in a gamma-ray background

Paul Bennett, Alireza Kargar, Leonard Cirignano, Hadong Kim, Kanai Shah

Proceedings Volume 10762, 107620Z (2018) https://doi.org/10.1117/12.2323695

KEYWORDS: Sensors, Diamond, Particles, Krypton, Gamma radiation, Cesium, Crystals, Strontium, Temperature metrology, Electronics

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Proceedings Article | 15 September 2017 Presentation + Paper

History and current status of strontium iodide scintillators

N. Cherepy, P. Beck, S. Payne, E. Swanberg, B. Wihl, S. Fisher, S. Hunter, P. Thelin, C. Delzer, S. Shahbazi, A. Burger, K. Shah, R. Hawrami, L. Boatner, M. Momayezi, K. Stevens, M. Randles, D. Solodovnikov

Proceedings Volume 10392, 1039202 (2017) https://doi.org/10.1117/12.2276302

KEYWORDS: Crystals, Sensors, Strontium, Radioisotopes, Scintillators, Europium, Gamma radiation, Spectrometers, Scintillation

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Proceedings Article | 2 November 2016 Presentation

Tl-based semiconductor and scintillators (Conference Presentation)

Kanai Shah

Proceedings Volume 9968, 99680Z (2016) https://doi.org/10.1117/12.2240060

KEYWORDS: Semiconductors, Scintillators, Sensors, Gamma radiation, Hard x-rays, Physics, Current controlled current source

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Proceedings Article | 30 September 2016 Presentation + Paper

Semiconductor neutron detectors

Andrey Gueorguiev, Huicong Hong, Joshua Tower, Hadong Kim, Leonard Cirignano, Arnold Burger, Kanai Shah

Proceedings Volume 9968, 99680P (2016) https://doi.org/10.1117/12.2237054

KEYWORDS: Sensors, Semiconductors, Signal detection, Crystals, Lithium, Semiconducting wafers, Absorption, Gamma radiation, Indium, Particles

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Proceedings Article | 9 September 2016 Paper

High energy resolution plastic scintillator

Edgar van Loef, Patrick Feng, Gary Markosyan, Urmila Shirwadkar, Patrick Doty, Kanai Shah

Proceedings Volume 9968, 996803 (2016) https://doi.org/10.1117/12.2237999

KEYWORDS: Scintillators, Gamma radiation, Sensors, Spectroscopy, Scintillation, Tin, X-rays, Oscilloscopes, Signal processing, Photomultipliers

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Proceedings Article | 27 August 2015 Paper

Auger compositional depth profiling of the metal contact-TlBr interface

A. Nelson, E. Swanberg, L. Voss, R. Graff, A. Conway, R. Nikolic, S. Payne, H. Kim, L. Cirignano, K. Shah

Proceedings Volume 9595, 959507 (2015) https://doi.org/10.1117/12.2186653

KEYWORDS: Thallium, Metals, Profiling, Platinum, Molybdenum, Interfaces, Sensors, Surface finishing, Scanning electron microscopy, Bromine

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Proceedings Article | 27 August 2015 Paper

Negative temporal cross covariance in SrI2:Eu

Vaibhav Bora, David Fastje, Harrison Barrett, Eric Clarkson, Lars Furenlid, Kanai Shah, Urmila Shirwadkar

Proceedings Volume 9595, 959504 (2015) https://doi.org/10.1117/12.2214406

KEYWORDS: Scintillation, Sensors, Gamma radiation, Signal detection, Crystals, Oscilloscopes, Scintillators, Photons, Interference (communication), Europium

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Proceedings Article | 26 August 2015 Paper

Linearity response of Ca2+-doped CeBr3 as a function of gamma-ray energy

Paul Guss, Michael Foster, Bryan Wong, F. Doty, Kanai Shah, Michael Squillante, Urmila Shirwadkar, Rastgo Hawrami, Josh Tower, Thomas Stampahar, Sanjoy Mukhopadhyay

Proceedings Volume 9593, 959304 (2015) https://doi.org/10.1117/12.2186181

KEYWORDS: Crystals, Calcium, Doping, Scintillators, Sensors, Spectroscopy, Ions, Cerium, Gamma radiation, Photons

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Proceedings Article | 12 September 2014 Paper

Advances in scintillators for medical imaging applications

Edgar van Loef, Kanai Shah

Proceedings Volume 9214, 92140A (2014) https://doi.org/10.1117/12.2065795

KEYWORDS: Scintillators, Positron emission tomography, Single photon emission computed tomography, Scintillation, Crystals, Sensors, Medical imaging applications, Gamma radiation, Image quality, Image resolution

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Proceedings Article | 9 September 2014 Paper

Strontium iodide instrument development for gamma spectroscopy and radioisotope identification

P. Beck, N. Cherepy, S. Payne, E. Swanberg, K. Nelson, P. Thelin, S. Fisher, S. Hunter, B. Wihl, K. Shah, R. Hawrami, A. Burger, L. Boatner, M. Momayezi, K. Stevens, M. Randles, D. Solodovnikov

Proceedings Volume 9213, 92130N (2014) https://doi.org/10.1117/12.2063056

KEYWORDS: Crystals, Sensors, Radioisotopes, Prototyping, Strontium, Scintillation, Data modeling, Performance modeling, Scintillators, Digital electronics

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Proceedings Article | 5 September 2014 Paper

Triplet harvesting plastic scintillators with neutron-gamma pulse shape discrimination

Edgar van Loef, Patrick Feng, Gary Markosyan, Urmila Shirwadkar, Patrick Doty, Kanai Shah

Proceedings Volume 9213, 921306 (2014) https://doi.org/10.1117/12.2061064

KEYWORDS: Scintillators, Scintillation, Iridium, Gamma radiation, Polymers, Energy transfer, X-rays, Oscilloscopes, Picosecond phenomena, Photography

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Proceedings Article | 5 September 2014 Paper

Oxidation/reduction reactions at the metal contact-TlBr interface: an x-ray photoelectron spectroscopy study

A. Nelson, E. Swanberg, L. Voss, R. Graff, A. Conway, R. Nikolic, S. Payne, H. Kim, L. Cirignano, K. Shah

Proceedings Volume 9213, 921313 (2014) https://doi.org/10.1117/12.2062037

KEYWORDS: Platinum, Molybdenum, Thallium, Chlorine, Metals, Sensors, Bromine, Photoemission spectroscopy, Surface finishing, X-rays

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Proceedings Article | 4 September 2014 Paper

The effect of guard ring on leakage current and spectroscopic performance of TlBr planar detectors

Alireza Kargar, Hadong Kim, Leonard Cirignano, Kanai Shah

Proceedings Volume 9215, 92150E (2014) https://doi.org/10.1117/12.2065908

KEYWORDS: Sensors, Electrodes, Spectroscopes, Gamma radiation, Thallium, Ceramics, Crystals, Amplifiers, Pulse generators, Active remote sensing

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Proceedings Article | 26 September 2013 Paper

Temperature behavior of CLYC/MPPC detectors

Jarek Glodo, Mickel McClish, Rastgo Hawrami, Patrick O'Dougherty, Josh Tower, Andrey Gueorguiev, Kanai Shah

Proceedings Volume 8852, 88520X (2013) https://doi.org/10.1117/12.2028235

KEYWORDS: Sensors, Gamma radiation, Crystals, Scintillators, Temperature metrology, Connectors, Silicon photomultipliers, Photomultipliers, Energy efficiency, Signal detection

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Proceedings Article | 26 September 2013 Paper

Photoemission analysis of chemically modified TlBr surfaces for improved radiation detectors

A. Nelson, J.-S. Lee, J. Stanford, W. Grant, L. Voss, P. Beck, R. Graff, E. Swanberg, A. Conway, R. Nikolic, S. Payne, H. Kim, L. Cirignano, K. Shah

Proceedings Volume 8852, 88520E (2013) https://doi.org/10.1117/12.2021675

KEYWORDS: Surface finishing, Thallium, Bromine, Chlorine, Sensors, Chemical analysis, Chemistry, Polishing, Heterojunctions, Synchrotron radiation

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Proceedings Article | 26 September 2013 Paper

Boron selenide semiconductor detectors for thermal neutron counting

Alireza Kargar, Joshua Tower, Leonard Cirignano, Kanai Shah

Proceedings Volume 8852, 88521M (2013) https://doi.org/10.1117/12.2027078

KEYWORDS: Sensors, Gamma radiation, Boron, Carbon, Crystals, Semiconductors, Absorption, Particles, Crystallography, Selenium

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Proceedings Article | 26 September 2013 Paper

Studies on Ca2+-doped CeBr3 scintillating materials

Paul Guss, Michael Foster, Bryan Wong, F. Patrick Doty, Kanai Shah, Michael Squillante, Urmila Shirwadkar, Rastgo Hawrami, Josh Tower, Ding Yuan

Proceedings Volume 8854, 885406 (2013) https://doi.org/10.1117/12.2021342

KEYWORDS: Crystals, Scintillators, Scintillation, Cerium, Optical properties, Electrons, Calcium, Sensors, Chemical species, Gamma radiation

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Proceedings Article | 24 October 2012 Paper

Latest advances in large diameter SrI:Eu and CLYC:Ce scintillators for isotope identification

R. Hawrami, C. Hines, I. Abselem, V. Biteman, J. Vaghini, J. Glodo, P. O'Dougherty, K. Shah, Nerine Cherepy, Stephen Payne, Arnold Burger, Lynn Boatner

Proceedings Volume 8507, 850716 (2012) https://doi.org/10.1117/12.945937

KEYWORDS: Crystals, Scintillators, Gamma radiation, Sensors, Scintillation, Quartz, Spectrometers, Chemical species, Control systems, Diamond

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Scintillator crystal detectors form the basis for many radiation detection devices. Therefore, a search for high light yield single crystal scintillators with improved energy resolution, large volume, and the potential for low cost, is an ongoing process that has increased in recent years due to a large demand in the area of nuclear isotope identification. Alkaline earth halides, elpasolites and rare earth halides are very interesting because many compositions from these crystal families provide efficient Ce3+/ Eu2+ luminescence, good proportionality and good energy resolution. They also have small band-gap leading to higher light yields. Ce3+and Eu2+ are efficient, and the emission wavelengths in the 350-500 nm region matches well with PMTs and a new generation of Siphotodiodes. In this presentation, we will the present progress made in the crystal growth of these compositions, and scintillator properties of large diameter SrI2:Eu2+ single transparent crystals. The crystals were grown successfully using the vertical Bridgeman technique. Crystals with different diameters of 1”, 1.3”, and 1.5” will be discussed. SrI2:Eu was discovered a half century ago, and was recently found to be an outstanding material for gamma ray-spectroscopy with high light yield, very good non-proportionality, and excellent energy resolution. We will also discuss growth and properties of larger Cs2LiYCl6 (CLYC) crystals. Recently, it has been shown that crystals from the elpasolite family, including CLYC, can be successfully employed for a dual gamma ray and neutron detection, which is possible with the help of pulse shape discrimination (PSD). PSD allows for recognition of an incident particle’s nature based on the shape of the corresponding scintillation pulse. CLYC has the potential to minimize the cost and complexity of dual sensing gamma ray and neutron spectrometers. We also address progress in growth of CLYC crystals with large diameters (1” and 2”) that are transparent and crack free.

Proceedings Article | 24 October 2012 Paper

Transparent garnet ceramic scintillators for gamma-ray detection

Yimin Wang, Gary Baldoni, William Rhodes, Charles Brecher, Ananya Shah, Urmila Shirwadkar, Jarek Glodo, Nerine Cherepy, Stephen Payne

Proceedings Volume 8507, 850717 (2012) https://doi.org/10.1117/12.956437

KEYWORDS: Ceramics, Garnet, Scintillators, Scintillation, Transparency, Crystals, Gamma radiation, Positron emission tomography, Optical properties, Gadolinium

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Proceedings Article | 17 October 2012 Paper

The uniformity and imaging properties of some new ceramic scintillators

George T. Chac, Brian Miller, Kanai Shah, Gary Baldoni, Kenneth Domanik, Vaibhav Bora, Nerine Cherepy, Zachary Seeley, H. Bradford Barber

Proceedings Volume 8508, 85080H (2012) https://doi.org/10.1117/12.966670

KEYWORDS: Scintillators, Ceramics, Gamma radiation, Imaging spectroscopy, Imaging systems, Sensors, Spectroscopy, Spatial resolution, Image intensifiers, Crystals

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Proceedings Article | 17 October 2012 Paper

Application of TlBr to nuclear medicine imaging

Leonard Cirignano, Hadong Kim, Alireza Kargar, Alexei Churilov, Guido Ciampi, William Higgins, Suyoung Kim, Bradford Barber, Kyle Haston, Kanai Shah

Proceedings Volume 8508, 850803 (2012) https://doi.org/10.1117/12.961447

KEYWORDS: Sensors, Single photon emission computed tomography, Crystals, Semiconductors, Gamma radiation, Solids, Signal attenuation, Scintillators, Nuclear medicine, Semiconductor materials

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Proceedings Article | 28 September 2011 Paper

Long-term room temperature stability of TlBr gamma detectors

A. Conway, L. Voss, A. Nelson, P. Beck, R. Graff, R. Nikolic, S. Payne, H. Kim, L. Cirignano, K. Shah

Proceedings Volume 8142, 81420J (2011) https://doi.org/10.1117/12.896713

KEYWORDS: Sensors, Gold, Bromine, Thallium, Crystals, Polishing, Chlorine, Etching, Electrodes, Surface finishing

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Proceedings Article | 28 September 2011 Paper

Performance of europium-doped strontium iodide, transparent ceramics and bismuth-loaded polymer scintillators

N. Cherepy, S. Payne, B. Sturm, S. O'Neal, Z. Seeley, O. Drury, L. K. Haselhorst, B. Rupert, R. Sanner, P. Thelin, S. Fisher, R. Hawrami, K. Shah, A. Burger, J. Ramey, L. Boatner

Proceedings Volume 8142, 81420W (2011) https://doi.org/10.1117/12.896656

KEYWORDS: Scintillators, Ceramics, Crystals, Strontium, Spectroscopy, Scintillation, Gamma radiation, Garnet, Bismuth, Radiography

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Proceedings Article | 28 September 2011 Paper

Lithium and boron based semiconductors for thermal neutron counting

Alireza Kargar, Joshua Tower, Huicong Hong, Leonard Cirignano, William Higgins, Kanai Shah

Proceedings Volume 8142, 81421P (2011) https://doi.org/10.1117/12.899363

KEYWORDS: Sensors, Gamma radiation, Boron, Crystals, Semiconductors, Lithium, Absorption, Chemical species, Selenium, Carbon

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Proceedings Article | 16 March 2011 Paper

6-Li enriched Cs2LiYCl6:Ce based thermal neutron detector coupled with CMOS solid-state photomultipliers for a portable detector unit

Chad Whitney, Christopher Stapels, Erik Johnson, Eric Chapman, Guy Alberghini, Jarek Glodo, Kanai Shah, James Christian

Proceedings Volume 7961, 79610U (2011) https://doi.org/10.1117/12.878225

KEYWORDS: Sensors, Gamma radiation, Crystals, CMOS sensors, Scintillation, Scintillators, Solid state electronics, Photomultipliers, Prototyping, Signal detection

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Proceedings Article | 3 September 2010 Paper

Continued development of room temperature semiconductor nuclear detectors

Hadong Kim, Leonard Cirignano, Alexei Churilov, Guido Ciampi, Alireza Kargar, William Higgins, Patrick O'Dougherty, Suyoung Kim, Michael Squillante, Kanai Shah

Proceedings Volume 7806, 780604 (2010) https://doi.org/10.1117/12.864147

KEYWORDS: Sensors, Mercury, Semiconductors, Gamma radiation, Spectroscopy, Crystals, Electrodes, Temperature metrology, Amplifiers, Thallium

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Proceedings Article | 12 September 2009 Paper

Dual gamma neutron detection with Cs[sub]2[/sub]LiLaCl[sub]6[/sub]

Jarek Glodo, Rastgo Hawrami, Edgar van Loef, William Higgins, Urmila Shirwadkar, Kanai Shah

Proceedings Volume 7449, 74490E (2009) https://doi.org/10.1117/12.830127

KEYWORDS: Cerium, Crystals, Sensors, Gamma radiation, Scintillators, Oscilloscopes, Luminescence, Spectroscopy, Scintillation, Homeland security

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Proceedings Article | 12 September 2009 Paper

SrI[sub]2[/sub] scintillator for gamma ray spectroscopy

N. Cherepy, B. Sturm, O Drury, T. Hurst, S. Sheets, L. Ahle, C. Saw, M. Pearson, S. Payne, A. Burger, L. Boatner, J. Ramey, E. van Loef, J. Glodo, R. Hawrami, W. Higgins, K. Shah, W. Moses

Proceedings Volume 7449, 74490F (2009) https://doi.org/10.1117/12.830016

KEYWORDS: Crystals, Gamma radiation, Scintillators, Spectroscopy, Scintillation, Strontium, X-ray diffraction, Europium, Crystal optics, Single crystal X-ray diffraction

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Proceedings Article | 12 September 2009 Paper

HgS: a rugged, stable semiconductor radiation detector material

Michael Squillante, William Higgins, Hadong Kim, Leonard Cirignano, Guido Ciampi, Alexei Churilov, Kanai Shah

Proceedings Volume 7449, 74491U (2009) https://doi.org/10.1117/12.829374

KEYWORDS: Mercury, Sensors, Crystals, Minerals, Semiconductors, Semiconductor materials, Gamma radiation, Scintillators, Manufacturing, Signal detection

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Proceedings Article | 2 September 2009 Paper

Lu2SiO5:Ce optical ceramic scintillator

Yimin Wang, William Rhodes, Gary Baldoni, Edgar van Loef, Jarek Glodo, Charles Brecher, Long Nguyen, Kanai Shah

Proceedings Volume 7393, 73930H (2009) https://doi.org/10.1117/12.826899

KEYWORDS: Ceramics, Crystals, Scintillation, Scintillators, Scanning electron microscopy, Transparency, Lutetium, Medical imaging applications, Gamma radiation, Particles

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Proceedings Article | 5 September 2008 Paper

Strontium iodide scintillators for high energy resolution gamma ray spectroscopy

Cody Wilson, Edgar van Loef, Jarek Glodo, Nerine Cherepy, Giulia Hull, Stephen Payne, Woon-Seng Choong, William Moses, Kanai Shah

Proceedings Volume 7079, 707917 (2008) https://doi.org/10.1117/12.806291

KEYWORDS: Crystals, Scintillation, Scintillators, Gamma radiation, Europium, Spectroscopy, Strontium, Polishing, Cerium, Patents

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Proceedings Article | 4 September 2008 Paper

Purification, crystal growth and detector performance of TlBr

Alexei Churilov, William Higgins, Guido Ciampi, Hadong Kim, Leonard Cirignano, Fred Olschner, Kanai Shah

Proceedings Volume 7079, 70790K (2008) https://doi.org/10.1117/12.794838

KEYWORDS: Sensors, Crystals, Diffraction, Sensor performance, Etching, Semiconductors, Annealing, Gamma radiation, Materials analysis, Thallium

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Proceedings Article | 15 April 2008 Paper

Nuclear material detection techniques

James Christian, Radia Sia, Purushottam Dokhale, Irina Shestakova, Vivek Nagarkar, Kanai Shah, Erik Johnson, Christopher Stapels, James Ryan, John Macri, Ulisse Bravar, Ka-Ngo Leung, Michael Squillante

Proceedings Volume 6945, 69451Q (2008) https://doi.org/10.1117/12.778730

KEYWORDS: Sensors, Gamma radiation, Imaging systems, Solid state electronics, Scintillators, Coded apertures, Standoff detection, Cameras, Telescopes, Detector development

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Proceedings Article | 18 October 2007 Paper

New scintillator compositions

W. Higgins, E. Van Loef, J. Glodo, A. Churilov, K. Shah

Proceedings Volume 6707, 670704 (2007) https://doi.org/10.1117/12.740834

KEYWORDS: Crystals, Scintillators, Gamma radiation, Spectrometers, Quartz, Oxygen, Copper, Diamond, Cesium, Photonic crystals

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Proceedings Article | 24 September 2007 Paper

Investigation of TlBr detector response under high-flux x-rays

Hadong Kim, Leonard Cirignano, Yuri Dmitriev, Mike Squillante, Philip Wong, Kanai Shah

Proceedings Volume 6706, 67061F (2007) https://doi.org/10.1117/12.734779

KEYWORDS: Sensors, X-rays, Polarization, X-ray detectors, Signal detection, Crystals, Electrons, Electrodes, Amplifiers, Gold

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Proceedings Article | 14 September 2005 Paper

A high efficiency small animal imaging system based on position sensitive avalanche photodiodes

Tobias Funk, Philippe Despres, William Barber, Kanai Shah, Bruce Hasegawa

Proceedings Volume 5923, 59230D (2005) https://doi.org/10.1117/12.624927

KEYWORDS: Imaging systems, Sensors, Spatial resolution, Single photon emission computed tomography, Reconstruction algorithms, Collimators, Avalanche photodetectors, Preclinical imaging, Avalanche photodiodes, Animal model studies

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Single photon emission computed tomography (SPECT) is an important technology for molecular imaging studies of small animals with an increasing demand for high performance imaging systems. We have designed a small animal imaging system based on position sensitive avalanche photodiodes (PSAPDs) detectors with the goal of submillimeter spatial resolution and high detection efficiency, which will allow us to minimize the radiation dose to the animal and to shorten the time needed for the imaging study. Our design will use fourteen 80×80 mm² PSAPD detectors, which can achieve an intrinsic spatial resolution of 0.5 mm. These detectors are arranged in two rings around the object and are equipped with pinhole collimators to produce magnified projection data. A mouse bed is positioned in the center of the detector rings and can be rocked about the central axis to increase angular sampling of the object. The performance of this imaging system and of a dual headed SPECT system has been simulated using a ray tracing program taking into account appropriate point spread functions. Projection data of a hot rod phantom with 84 angular samples have been simulated. Appropriate Poisson noise has been added to the data to simulate an acquisition time of 15 min and an activity of 18.5 MBq distributed in the phantom. Both sets of data were reconstructed with an ML-EM reconstruction algorithm. We also derived spatial resolution and detection efficiency from analytical equations and compared the performance of our system to a variety of other small animal SPECT imaging systems. Simulations show that our proposed system produces a spatial resolution of 0.9 mm which is in good agreement with the resolution derived from analytical equations. In contrast, simulations of the dual headed SPECT system produce a spatial resolution of 1.1 mm. In comparison to other small animal SPECT systems, our design will offer a detection efficiency which is at least 2-fold higher at better or comparable spatial resolution. These results suggest that detectors based on PSAPD technology can be used to improve the design of small animal SPECT imaging systems considerably. Our small animal system design is very compact and can achieve high resolution and detection efficiency.

Proceedings Article | 6 May 2004 Paper

Improved properties of PbI2 x-ray imagers with tighter process control and using positive bias voltage

George Zentai, Larry Partain, Raisa Pavlyuchkova, Cesar Proano, Gary Virshup, Paul Bennett, Kanai Shah, Yuri Dmitriev, Jerry Thomas

Proceedings Volume 5368, (2004) https://doi.org/10.1117/12.535994

KEYWORDS: Imaging systems, X-rays, X-ray imaging, Modulation transfer functions, Lead, Amorphous silicon, Process control, Electrodes, Glasses, Electrons

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Proceedings Article | 20 January 2004 Paper

Evaluation of CZT detectors with capacitive Frisch grid structure

Leonard Cirignano, Hadong Kim, Kanai Shah, Misha Klugerman, Philip Wong, Michael Squillante, Longxia Li

Proceedings Volume 5198, (2004) https://doi.org/10.1117/12.507891

KEYWORDS: Sensors, Cesium, Metals, Americium, Electrons, Spectroscopes, Collimation, Dielectrics, Semiconductors, Gamma radiation

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Proceedings Article | 20 January 2004 Paper

New progress in large-size CZT single-crystal growth for nuclear radiation detectors

Longxia Li, Fengying Lu, Chun Lee, H. Walter Yao, Arnold Burger, M. Groza, G. Wright, Ralph James, Richard Olsen, Paul Luke, Kanai Shah, Leonard Cirignano, Michael Squillante, Donald Ouimette

Proceedings Volume 5198, (2004) https://doi.org/10.1117/12.507745

KEYWORDS: Cadmium, Crystals, Sensors, Indium, Doping, Lithium, Gamma radiation, Nuclear radiation, Semiconducting wafers, Sodium

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Proceedings Article | 22 September 2003 Paper

Recent advances in very large area avalanche photodiodes

Michael Squillante, James Christian, Gerald Entine, Richard Farrell, Arieh Karger, Mickel McClish, Richard Myers, Kanai Shah, David Taylor, Kofi Vanderpuye, Peter Waer, Mitchell Woodring

Proceedings Volume 5071, (2003) https://doi.org/10.1117/12.517444

KEYWORDS: Avalanche photodetectors, LIDAR, Sensors, Silicon, Avalanche photodiodes, Laser induced breakdown spectroscopy, Manufacturing, Gamma radiation, Chemical elements, X-rays

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Proceedings Article | 5 June 2003 Paper

Mercuric iodide and lead iodide x-ray detectors for radiographic and fluoroscopic medical imaging

George Zentai, Larry Partain, Raisa Pavlyuchkova, Cesar Proano, Gary Virshup, L. Melekhov, A. Zuck, Barry Breen, O. Dagan, A. Vilensky, Michael Schieber, Haim Gilboa, Paul Bennet, Kanai Shah, Yuriy Dmitriyev, Jerry Thomas, Martin Yaffe, David Hunter

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.480227

KEYWORDS: Imaging systems, X-rays, Lead, Modulation transfer functions, Photoresistors, Sensors, X-ray detectors, Medical imaging, X-ray imaging, Image resolution

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Mercuric iodide (HgI₂) and lead iodide (PbI₂) have been under development for several years as direct converter layers in digital x-ray imaging. Previous reports have covered the basic electrical and physical characteristics of these and several other materials. We earlier reported on 5cm x 5cm and 10cm x 10cm size imagers, direct digital radiography X-ray detectors, based on photoconductive polycrystalline mercuric iodide deposited on a flat panel thin film transistor (TFT) array, as having great potential for use in medical imaging, NDT, and security applications. This paper, presents results and comparison of both lead iodide and mercuric iodide imagers scaled up to 20cm x 25cm sizes. Both the mercuric iodide and lead iodide direct conversion layers are vacuum deposited onto TFT array by Physical Vapor Deposition (PVD). This process has been successfully scaled up to 20cm x 25cm -- the size required in common medical imaging applications. A TFT array with a pixel pitch of 127 microns was used for this imager. In addition to increasing detector size, more sophisticated, non-TFT based small area detectors were developed in order to improve analysis methods of the mercuric and lead iodide photoconductors. These small area detectors were evaluated in radiographic mode, continuous fluoroscopic mode and pulsed fluoroscopic mode. Mercuric iodide coating thickness ranging between 140 microns and 300 microns and lead iodide coating thickness ranging between 100 microns and 180 microns were tested using beams with energies between 40 kVp and 100 kVp, utilizing exposure ranges typical for both fluoroscopic and radiographic imaging. Diagnostic quality radiographic and fluoroscopic images have been generated at up to 15 frames per second. Mercuric iodide image lag appears adequate for fluoroscopic imaging. The longer image lag characteristics of lead iodide make it only suitable for radiographic imaging. For both material the MTF is determined primarily by the aperture and pitch of the TFT array (Nyquist frequency of ~3.93 mm^-1 (127 micron pixel pitch).

Proceedings Article | 10 January 2003 Paper

Development of a large single-crystal (3-inch ingot) CdZnTe for large-volume nuclear radiation detectors

Longxia Li, Fengying Lu, Chun Lee, Gomez Wright, David Rhiger, Sanghamitra Sen, Kanai Shah, Michael Squillante, Leonard Cirignano, Ralph James, Arnold Burger, Paul Luke, Richard Olson

Proceedings Volume 4784, (2003) https://doi.org/10.1117/12.453826

KEYWORDS: Sensors, Crystals, Tellurium, Zinc, Cadmium, Nuclear radiation, Gamma radiation, Gold, X-rays, Semiconducting wafers

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Proceedings Article | 26 November 2002 Paper

Current mode operation of a Cd0.9Zn0.1Te detector for CT imaging

William Barber, Koji Iwata, Bruce Hasegawa, Paul Bennett, Leonard Cirignano, Kanai Shah

Proceedings Volume 4786, (2002) https://doi.org/10.1117/12.455944

KEYWORDS: Sensors, X-rays, X-ray computed tomography, Single photon emission computed tomography, X-ray detectors, Zinc, Tellurium, X-ray imaging, Cadmium, Imaging systems

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Proceedings Article | 28 June 2001 Paper

Comparative study of Pbl2 and Hgl2 as direct detector materials for high-resolution x-ray image sensors

Robert Street, Marcelo Mulato, Michael Schieber, Haim Hermon, Kanai Shah, Paul Bennett, Yuri Dmitryev, Jackson Ho, Rachel Lau, Evgenie Meerson, Steve Ready, Benjamin Reisman, Y. Sado, Koenraad Van Schuylenbergh, Alexander Vilensky, Asaf Zuck

Proceedings Volume 4320, (2001) https://doi.org/10.1117/12.430858

KEYWORDS: X-rays, X-ray imaging, Signal attenuation, Imaging systems, Absorption, Electrons, Image sensors, Mammography, Chlorine, X-ray detectors

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Proceedings Article | 21 November 2000 Paper

Characterization of multi-element CZT arrays

Leonard Cirignano, Kanai Shah, Paul Bennett, Longxia Li, Fengying Lu, Joseph Buturlia, H. Walter Yao, Gomez Wright, Ralph James

Proceedings Volume 4141, (2000) https://doi.org/10.1117/12.407600

KEYWORDS: Sensors, Collimation, Multi-element lenses, Gamma radiation, Detector arrays, Chemical elements, Particles, Chlorine, Floods, X-rays

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Proceedings Article | 25 April 2000 Paper

High-resolution direct-detection x-ray imagers

Robert Street, Steve Ready, Jeffrey Rahn, Marcelo Mulato, Kanai Shah, Paul Bennett, Ping Mei, Jeng-Ping Lu, Raj Apte, Jackson Ho, Koenraad Van Schuylenbergh, Francesco Lemmi, James Boyce, Per Nylen, Michael Schieber, Haim Hermon

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384516

KEYWORDS: X-rays, Modulation transfer functions, Photoresistors, X-ray imaging, Interference (communication), Image sensors, Absorption, Spatial resolution, X-ray detectors, Sensors

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Proceedings Article | 19 October 1999 Paper

Bismuth iodide crystals as a detector material: some optical and electrical properties

Yuriy Dmitriyev, Paul Bennett, Leonard Cirignano, Mikhail Klugerman, Kanai Shah

Proceedings Volume 3768, (1999) https://doi.org/10.1117/12.366625

KEYWORDS: Crystals, Bismuth, Sensors, Lead, X-ray detectors, X-rays, Iodine, Chemical species, Thulium, Crystallography

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Proceedings Article | 11 October 1999 Paper

Characterization of screen-printed dye-sensitized nanocrystalline TiO2 solar cells

Tapan Gupta, Leonard Cirignano, Kanai Shah, Larry Moy, David Kelly, Michael Squillante, Gerald Entine, Greg Smestad

Proceedings Volume 3789, (1999) https://doi.org/10.1117/12.367565

KEYWORDS: Ruthenium, Solar cells, Glasses, Electrons, Scanning electron microscopy, Quantum efficiency, X-ray diffraction, Particles, Electrodes, Titanium dioxide

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Proceedings Article | 6 October 1999 Paper

Progress in developing a combined x-ray CT and SPECT system using CdZnTe detector

Koji Iwata, Bruce Hasegawa, Colby Boles, Paul Bennett, Kanai Shah, Bernhard Boser

Proceedings Volume 3770, (1999) https://doi.org/10.1117/12.368170

KEYWORDS: Sensors, X-rays, Electronics, X-ray detectors, Single photon emission computed tomography, Gamma radiation, Digital electronics, Digital signal processing, X-ray computed tomography, Imaging systems

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Proceedings Article | 6 October 1999 Paper

PbI2 for high-resolution digital x-ray imaging

Kanai Shah, Paul Bennett, Yuriy Dmitriyev, Leonard Cirignano, Misha Klugerman, Michael Squillante, Robert Street, Jeffrey Rahn, Steve Ready

Proceedings Volume 3770, (1999) https://doi.org/10.1117/12.368179

KEYWORDS: Lead, Sensors, X-rays, Imaging systems, X-ray imaging, Modulation transfer functions, X-ray detectors, Image resolution, Spatial resolution, Crystals

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Proceedings Article | 6 October 1999 Paper

Planar APD arrays for high-resolution PET

Kanai Shah, Richard Farrell, Leonard Cirignano, Ronald Grazioso, Paul Bennett, Simon Cherry, Yiping Shao

Proceedings Volume 3770, (1999) https://doi.org/10.1117/12.368173

KEYWORDS: Avalanche photodetectors, Positron emission tomography, Crystals, Quantum efficiency, Sensors, Scintillators, Silicon, Spatial resolution, Scintillation, Semiconducting wafers

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Proceedings Article | 28 May 1999 Paper

X-ray imaging using lead iodide as a semiconductor detector

Robert Street, Jeffrey Rahn, Steve Ready, Kanai Shah, Paul Bennett, Yuriy Dmitriyev, Ping Mei, Jeng-Ping Lu, Raj Apte, Jackson Ho, Koenraad Van Schuylenbergh, Francesco Lemmi, James Boyce, Per Nylen

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349504

KEYWORDS: X-rays, X-ray imaging, Imaging systems, Absorption, Lead, Image sensors, Sensors, Modulation transfer functions, Photoresistors, Electrons

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Proceedings Article | 24 July 1998 Paper

Large-area x-ray image sensing using a Pbl2 photoconductor

Robert Street, Kanai Shah, Steve Ready, Raj Apte, Paul Bennett, Misha Klugerman, Yuriy Dmitriyev

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317027

KEYWORDS: X-rays, Photoresistors, Absorption, X-ray imaging, Imaging systems, Amorphous silicon, Image sensors, Ionization, Metals, Modulation transfer functions

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Proceedings Article | 1 July 1998 Paper

X-ray imaging with semiconductor films

Kanai Shah, Paul Bennett, Leonard Cirignano, Yuriy Dmitriyev, Mikhail Klugerman, Krishna Mandal, Larry Moy, Robert Street

Proceedings Volume 3446, (1998) https://doi.org/10.1117/12.312883

KEYWORDS: X-rays, Sensors, X-ray imaging, Lead, X-ray detectors, Spatial resolution, Imaging systems, Amorphous silicon, Scintillators, Electrodes

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Proceedings Article | 2 May 1997 Paper

Lead iodide films for x-ray imaging

Kanai Shah, Paul Bennett, Mikhail Klugerman, Larry Moy, Gerald Entine, Donald Ouimette, Richard Aikens

Proceedings Volume 3032, (1997) https://doi.org/10.1117/12.274007

KEYWORDS: Lead, Sensors, X-rays, X-ray imaging, Signal detection, X-ray detectors, Spatial resolution, Modulation transfer functions, Crystals, Photons

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Proceedings Article | 15 June 1995 Paper

Photoconducting ultraviolet detectors based on GaN films grown by electron cyclotron resonance molecular beam epitaxy

Mira Misra, Theodore Moustakas, Robert Vaudo, Rajminder Singh, Kanai Shah

Proceedings Volume 2519, (1995) https://doi.org/10.1117/12.211915

KEYWORDS: Sensors, Gallium nitride, X-rays, Ultraviolet detectors, Ultraviolet radiation, X-ray detectors, Molecular beam epitaxy, Photons, Photodiodes, Transmittance

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Proceedings Article | 22 December 1992 Paper

Computer simulation of gamma-ray spectra from semiconductor detectors

Jim Lund, Fred Olschner, Kanai Shah

Proceedings Volume 1734, (1992) https://doi.org/10.1117/12.138597

KEYWORDS: Sensors, Monte Carlo methods, Gamma radiation, Computer simulations, Semiconductors, Sensor performance, Electric field sensors, Convolution, Analytical research, Numerical simulations

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Proceedings Article | 22 December 1992 Paper

InI photodetectors for scintillation spectroscopy

Kanai Shah, Larry Moy, John Zhang, S. Medrick, Fred Olschner, Michael Squillante

Proceedings Volume 1734, (1992) https://doi.org/10.1117/12.138585

KEYWORDS: Photodetectors, Crystals, Sensors, Scintillation, Quantum efficiency, Scintillators, Spectrometers, Semiconductors, Spectroscopy, Electrodes

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Proceedings Article | 22 December 1992 Paper

Silicon-drift photodiodes for gamma-ray scintillator photodetection

Fred Olschner, Jim Lund, Kanai Shah, Michael Squillante

Proceedings Volume 1734, (1992) https://doi.org/10.1117/12.138592

KEYWORDS: Silicon, Photodiodes, Photodetectors, Scintillators, Gamma radiation, Measurement devices, Capacitance, Scintillation, Sensors, Spectroscopes

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Proceedings Article | 22 December 1992 Paper

Recent developments in the search for new semiconductor gamma-ray detector materials

Jim Lund, Fred Olschner, Kanai Shah, Michael Squillante

Proceedings Volume 1734, (1992) https://doi.org/10.1117/12.138582

KEYWORDS: Sensors, Semiconductors, Semiconductor materials, Crystals, Germanium, Gallium arsenide, Detector development, Gamma radiation, Silicon, Compound semiconductors

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