Dr. Karim Salaudin Karim Profile

Dr. Karim Salaudin Karim

Professor at Univ. of Waterloo

SPIE Involvement:

Conference Program Committee | Author

Publications (78)

Proceedings Article | 1 April 2024 Presentation + Paper

Kidney stone compositional analysis and identification using a benchtop high-resolution multi-modal x-ray phase-contrast micro-CT imaging system

Abdollah Pil-Ali, Zachary Birch, Sahar Adnani, Chris Scott, Karim Karim

Proceedings Volume 12925, 129250K (2024) https://doi.org/10.1117/12.3005886

KEYWORDS: X-rays, X-ray imaging, Renal calculi, Imaging systems, X-ray detectors, Signal attenuation, Scattering, Minerals, Calcium, Phosphates

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Proceedings Article | 1 April 2024 Poster + Paper

Enhancing temporal performance of a-Se detectors using a low-temperature hole-blocking bilayer design

Sahar Adnani, Abdollah Pil-Ali, Karim Karim

Proceedings Volume 12925, 1292538 (2024) https://doi.org/10.1117/12.3009196

KEYWORDS: Dark current, Sensors, Electrodes, Selenium, X-rays, Design, Baking, Interfaces, X-ray detectors, Mammography

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Proceedings Article | 7 April 2023 Presentation + Paper

Multimodal single-shot x-ray phase-contrast imaging using a high-resolution micropillar-based grating

Abdollah Pil-Ali, Serena Qinyun Shi, Sahar Adnani, Peter Noël, Karim Karim

Proceedings Volume 12463, 1246309 (2023) https://doi.org/10.1117/12.2655809

KEYWORDS: X-rays, X-ray imaging, X-ray detectors, Imaging systems, Silicon, Absorption, Particles, Electroplating

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Grating-based X-ray phase-contrast imaging (XPCi) systems offer higher sensitivity compared to other XPCi methods; however, realizing a high-resolution, compact, dose-efficient imaging system has been a significant challenge from technological and practical points of view until now. X-ray gratings quality and characteristics directly determine the final imaging quality, where a proper grating fabrication process can potentially minimize image artifacts and increase the system visibility. To achieve a high-resolution, compact, dose-efficient XPCi system, high-resolution detectors and high-resolution X-ray absorption gratings are a must. Moreover, an efficient image processing method is required to retrieve multimodal XPCi information—transmission, refraction (phase-contrast), and dark-field—efficiently and simultaneously. In this work, we report on a compact XPCi system that enables multimodal information retrieval through single-shot imaging with two-directional sensitivity. We first present an elegant cost-effective fabrication method to make high-resolution micropillar-based X-ray absorption gratings. A prototype 2D grating is fabricated with micropillars with 4 μm in diameter, periodicity of 16.3 μm, and aspect ratio of more than 40. This grating is then employed along with a prototype hybrid a-Se/CMOS direct conversion high-resolution X-ray detector with a pixel pitch of 8 μm in a compact system with a polychromatic microfocus source to perform X-ray phase-contrast imaging of various samples. We successfully demonstrate a single-shot XPCi and retrieve multimodal XPCi data with transmission and dark-field metrics. The final system is a promising candidate for XPCi applications as it facilitates single-shot imaging, which reduces the exposure dose on samples and yields multimodal XPCi images efficiently, all in a compact bench-top setup. The delivered X-ray dose at the sample, resolution of the system, and compactness of the reported imaging setup are potentially beneficial for ex vivo, in vivo, and computed tomography (CT) imaging applications.

Proceedings Article | 4 April 2022 Presentation + Paper

Investigation of position linearity in position-sensitive microstrip amorphous selenium-based detector

Sahar Adnani, Abdollah Pil-Ali, Celal Con, Karim Karim

Proceedings Volume 12031, 120310M (2022) https://doi.org/10.1117/12.2613306

KEYWORDS: Sensors, Electrodes, Photons, Single photon emission computed tomography, Spatial resolution, Light sources, Signal detection, Selenium, Scintillators

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Proceedings Article | 4 April 2022 Poster + Presentation + Paper

Improving adhesion quality of SU-8 to gold thin film for absorption grating fabrication in x-ray phase-contrast imaging

Abdollah Pil-Ali, Mohammad Soltani, Sahar Adnani, Muhammed Kayaharman, Mahla Poudineh, Bo Cui, Karim Karim

Proceedings Volume 12031, 120313M (2022) https://doi.org/10.1117/12.2613026

KEYWORDS: Phase contrast, Fabrication, Thin films, Gold, X-rays, Absorption, X-ray imaging, Chromium, Electroplating, Thin film coatings, Silicon, Scanning electron microscopy

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Proceedings Article | 4 April 2022 Poster + Presentation + Paper

A novel multi-layer grating structure for x-ray phase-contrast imaging

Abdollah Pil-Ali, Mohammad Soltani, Sahar Adnani, Bo Cui, Karim Karim

Proceedings Volume 12031, 120313J (2022) https://doi.org/10.1117/12.2613038

KEYWORDS: X-rays, X-ray imaging, Gold, X-ray lithography, Ultraviolet radiation, Chromium, Absorption, Lithography, Optical design, Electroplating, Multilayers, Fabrication, Phase contrast, High aspect ratio silicon micromachining

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Proceedings Article | 4 April 2022 Poster + Presentation + Paper

Self-aligned fabrication of high-aspect ratio high-resolution x-ray gratings

Abdollah Pil-Ali, Sahar Adnani, Pranav Gavirneni, Seokjee Shin, Bahareh Sadeghimakki, Mahla Poudineh, William Wong, Karim Karim

Proceedings Volume 12031, 120313K (2022) https://doi.org/10.1117/12.2613059

KEYWORDS: X-rays, Lithography, Photomasks, X-ray imaging, Electroplating, Ultraviolet radiation, Scanning electron microscopy, Gold, X-ray lithography, Thin films

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Proceedings Article | 4 April 2022 Presentation

Energy resolution of amorphous selenium detectors: conventional vs unipolar charge sensing

Ahmet Camlica, Denny Lee, Hyunsuk Jang, M. Zahangir Kabir, Karim Karim

Proceedings Volume PC12031, PC120310G (2022) https://doi.org/10.1117/12.2613030

KEYWORDS: Sensors, Selenium, Photon counting, Electric field sensors, Spatial resolution, Time metrology, Surgery, Spectroscopy, Spectroscopes, Single photon

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Proceedings Article | 15 February 2021 Poster + Presentation + Paper

Challenges of employing a high resolution x-ray detector in a coded-aperture x-ray phase-contrast imaging system

Abdollah Pil-Ali, Sahar Adnani, Christopher Scott, Karim Karim

Proceedings Volume 11595, 115954O (2021) https://doi.org/10.1117/12.2582351

KEYWORDS: X-ray detectors, X-ray imaging, Imaging systems, Absorption, X-rays, Image resolution, Environmental sensing, Sensors, Phase contrast, Mask making

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Proceedings Article | 15 February 2021 Presentation + Paper

Monte Carlo simulation of an amorphous selenium-based multi-layer photon-counting detector for SPECT applications

Sahar Adnani, Abdollah Pil-Ali, Christopher Scott, Karim Karim

Proceedings Volume 11595, 1159515 (2021) https://doi.org/10.1117/12.2582325

KEYWORDS: Sensors, Single photon emission computed tomography, Monte Carlo methods, Photon transport, Photodetectors, Modulation transfer functions, Spatial resolution, Point spread functions, Energy efficiency, Compton scattering

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Proceedings Article | 15 February 2021 Presentation + Paper

Evaluation of edge-illumination and propagation-based x-ray phase contrast imaging methods for high resolution imaging application

Abdollah Pil-Ali, Sahar Adnani, Christopher Scott, Karim Karim

Proceedings Volume 11595, 115951N (2021) https://doi.org/10.1117/12.2582225

KEYWORDS: X-rays, X-ray imaging, Image resolution, X-ray detectors, Visibility, Systems modeling, Sensors, Mammography, Data modeling, Absorption

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Proceedings Article | 16 March 2020 Paper

A comparison of phase retrieval methods for propagation-based contrast x-ray imaging with polychromatic sources

Rhiannon Lohr, Chris Scott, Abdollah Pil-Ali, Karim Karim

Proceedings Volume 11312, 1131251 (2020) https://doi.org/10.1117/12.2544419

KEYWORDS: Phase retrieval, X-ray imaging, Contrast transfer function, X-rays, Absorption, Signal attenuation, Image retrieval, Sensors, Computer simulations, Phase shifts

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Proceedings Article | 16 March 2020 Paper

Performance of amorphous selenium-based unipolar charge sensing detector for photon counting x-ray imaging

Ahmet Camlica, Denny Lee, Hyunsuk Jang, Salman Arnab, Yuan Fang, M. Kabir, Karim Karim

Proceedings Volume 11312, 113120G (2020) https://doi.org/10.1117/12.2550318

KEYWORDS: Sensors, Electrodes, Signal detection, Photon counting, Selenium, Photoresistors, Electric field sensors, Near field, X-ray imaging, Photodetectors

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Proceedings Article | 1 March 2019 Presentation + Paper

Performance evaluation of a Se/CMOS prototype x-ray detector with the Apodized Aperture Pixel (AAP) design

Tomi Nano, Christopher Scott, Yunzhe Li, Celal Con, Karim Karim, Ian Cunningham

Proceedings Volume 10948, 1094816 (2019) https://doi.org/10.1117/12.2512954

KEYWORDS: Sensors, Modulation transfer functions, X-rays, X-ray detectors, Prototyping, Signal to noise ratio, X-ray imaging, Signal detection, Photons, Selenium

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Proceedings Article | 12 March 2018 Paper

Increased temporal resolution of amorphous selenium detector using preferential charge sensing approach

Ahmet Camlica, Denny Lee, Karim Karim

Proceedings Volume 10573, 105735W (2018) https://doi.org/10.1117/12.2293889

KEYWORDS: Sensors, Electrodes, X-rays, Selenium, Electrons, Spatial resolution, Real time imaging, Temporal resolution, Photoresistors, X-ray detectors

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Amorphous selenium (a-Se) is a direct conversion photoconductor capable of very high spatial resolution that can enable early detection of small and subtle lesions. A-Se also offers cost effective and reliable coupling to large area readout circuitry. Currently, the highest performance commercial flat panel detectors used for mammography are based on a-Se technology. However, this inherent spatial resolution has not been leveraged for real-time imaging applications, e.g. micro- angiography for imaging fine brain vessels that requires spatial resolution approaching 20 lp/mm, which is achievable with selenium technology. The challenge is that a-Se detectors suffer from memory artifacts such as lag that limits the frame rate of the X-ray imager. The frame rate reduction is attributed primarily to lag, which manifests itself as an increased dark conductivity after an X-ray exposure. Increased lag degrades the temporal response of the detector and makes a-Se photoconductor impractical for real-time imaging. Furthermore, high ionization energy required for electron-hole pair creation with a-Se limits the sensitivity of detector for a given X-ray dose, achieving a quantum noise limited system become a challenge. In this study, we investigate preferential sensing of those charge carriers having a higher mobility, i.e. holes for a-Se, to improve the temporal response of a-Se detectors for real-time imaging. A new preferential charge sensing detector with a field shaping internal grid, called Multi Pixel Proportional Counter, is fabricated and tested under the typical clinical usage conditions similar to that of fluoroscopy. The fabricated detector offers high frame rate and low noise imaging through avalanche gain. Conventional a-Se detectors are also fabricated for comparison purposes. Experimental results show that image lag as low as 1% can be achieved with the new structure with an internal grid while the conventional detector exhibits higher lag around 5%.

Proceedings Article | 9 March 2018 Paper

A novel radiation imaging detector with proportional charge gain

Denny Lee, Hyunsuk Jang, Ahmet Camlica, Karim Karim

Proceedings Volume 10573, 105735X (2018) https://doi.org/10.1117/12.2293429

KEYWORDS: Electrodes, Sensors, Selenium, Dielectrics, Interfaces, Image sensors, Ionization, Electrons, Image processing, Digital imaging

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Proceedings Article | 29 August 2017 Paper

Feasibility of current mediated amorphous silicon active pixel sensor readout circuits for large area diagnostic medical imaging

K. Karim

Proceedings Volume 10313, 103133M (2017) https://doi.org/10.1117/12.2283926

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Proceedings Article | 29 March 2016 Paper

Theoretical and Monte Carlo optimization of a stacked three-layer flat-panel x-ray imager for applications in multi-spectral diagnostic medical imaging

Sebastian Lopez Maurino, Aldo Badano, Ian Cunningham, Karim Karim

Proceedings Volume 9783, 97833Z (2016) https://doi.org/10.1117/12.2217085

KEYWORDS: Sensors, X-ray imaging, X-ray detectors, Diagnostics, Monte Carlo methods, Dual energy imaging, X-rays, Radiography, Medical imaging, Image quality, Scintillators, Photons, Imaging systems, Signal detection, Tissues

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Proceedings Article | 22 March 2016 Paper

A novel x-ray detector design with higher DQE and reduced aliasing: Theoretical analysis of x-ray reabsoprtion in detector converter material

Tomi Nano, Terenz Escartin, Karim Karim, Ian Cunningham

Proceedings Volume 9783, 978318 (2016) https://doi.org/10.1117/12.2217287

KEYWORDS: Quantum efficiency, Image quality, X-ray detectors, Sensors, X-ray imaging, Selenium, Signal to noise ratio, Photons, Interference (communication)

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Proceedings Article | 22 March 2016 Paper

Quantitative comparison using generalized relative object detectability (G-ROD) metrics of an amorphous selenium detector with high resolution microangiographic fluoroscopes (MAF) and standard flat panel detectors (FPD)

M. Russ, A. Shankar, A. Jain, S. V. Setlur Nagesh, C. Ionita, C. Scott, K. Karim, D. Bednarek, S. Rudin

Proceedings Volume 9783, 97833N (2016) https://doi.org/10.1117/12.2216733

KEYWORDS: Sensors, Selenium, CMOS sensors, Sensor performance, Image sensors, Optical spheres, Modulation transfer functions, Performance modeling, X-ray imaging, Spatial frequencies

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Proceedings Article | 18 March 2015 Paper

Apodized-aperture pixel design to increase high-frequency DQE and reduce noise aliasing in x-ray detectors

Elina Ismailova, Karim Karim, Ian Cunningham

Proceedings Volume 9412, 94120D (2015) https://doi.org/10.1117/12.2082020

KEYWORDS: Sensors, X-ray detectors, Signal detection, X-rays, Modulation transfer functions, Spatial frequencies, CMOS sensors, Interference (communication), Selenium, X-ray imaging

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Proceedings Article | 19 March 2014 Paper

Amorphous selenium direct detection CMOS digital x-ray imager with 25 micron pixel pitch

Christopher Scott, Shiva Abbaszadeh, Sina Ghanbarzadeh, Gary Allan, Michael Farrier, Ian Cunningham, Karim Karim

Proceedings Volume 9033, 90331G (2014) https://doi.org/10.1117/12.2043770

KEYWORDS: Modulation transfer functions, X-rays, X-ray imaging, CMOS sensors, Imaging systems, Sensors, Spatial resolution, Selenium, X-ray detectors, Gold

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Proceedings Article | 9 September 2013 Paper

Using segmented models for initial mask perturbation and OPC speedup

Ayman Hamouda, Mohab Anis, Karim Karim

Proceedings Volume 8880, 88801I (2013) https://doi.org/10.1117/12.2027718

KEYWORDS: Optical proximity correction, Model-based design, Photomasks, Image segmentation, Optical lithography, Printing, Data modeling, Ions, Resolution enhancement technologies, Lithography

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Proceedings Article | 29 May 2013 Paper

A microfabricated, low dark current a-Se detector for measurement of microplasma optical emission in the UV for possible use on-site

Shiva Abbaszadeh, Karim Karim, Vassili Karanassios

Proceedings Volume 8726, 87260S (2013) https://doi.org/10.1117/12.2016229

KEYWORDS: Sensors, Ultraviolet radiation, Spectroscopy, Electrodes, Fiber optics, Solid state electronics, Fiber optics sensors, Chemical analysis, Monochromators, Photons

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Proceedings Article | 19 March 2013 Paper

Spatial resolution characteristics of a-Se imaging detectors using Monte Carlo methods with detailed spatiotemporal transport of x-rays, electrons, and electron-hole pairs under applied bias

Yuan Fang, Andreu Badal, Aldo Badano, Karim Karim

Proceedings Volume 8668, 86683R (2013) https://doi.org/10.1117/12.2007436

KEYWORDS: Sensors, Monte Carlo methods, X-rays, X-ray detectors, Modulation transfer functions, Photons, Electrons, Spatial resolution, 3D modeling, Quantum efficiency

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Proceedings Article | 19 March 2013 Paper

Fabrication and characterization of a novel x-ray silicon detector

Kyung-Wook Shin, Karim Karim

Proceedings Volume 8668, 86683S (2013) https://doi.org/10.1117/12.2007900

KEYWORDS: Silicon, Sensors, Electrodes, Plasma enhanced chemical vapor deposition, X-ray detectors, Proteins, X-rays, Semiconducting wafers, Reactive ion etching, Crystallography

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Proceedings Article | 6 March 2013 Paper

Low dark current and high dynamic range a-Si:H MSM photodetector for large area medical imaging

Sina Ghanbarzadeh, Shiva Abbaszadeh, Michael Adachi, Karim Karim

Proceedings Volume 8668, 86683U (2013) https://doi.org/10.1117/12.2007973

KEYWORDS: Sensors, Interfaces, Photodetectors, Amorphous silicon, Silicon, High dynamic range imaging, Electrodes, Medical imaging, PIN photodiodes, Thin films

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Proceedings Article | 6 March 2013 Paper

Characterization of a digital x-ray detector for region of interest tuberculosis screening

Ryan Mann, Ian Cunningham, Karim Karim

Proceedings Volume 8668, 86685H (2013) https://doi.org/10.1117/12.2005949

KEYWORDS: Sensors, X-ray detectors, Imaging systems, Modulation transfer functions, X-rays, Radiography, Chest imaging, Chest, Diagnostics, Amorphous silicon

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Proceedings Article | 6 March 2013 Paper

Application of organic semiconductors in amorphous selenium based photodetectors for high performance X-ray imaging

Shiva Abbaszadeh, Zhechen Du, Nicholas Allec, Karim Karim

Proceedings Volume 8668, 86683Q (2013) https://doi.org/10.1117/12.2006705

KEYWORDS: Sensors, Electric field sensors, Photodetectors, Selenium, Organic materials, Organic semiconductors, X-ray imaging, Ionization, Electrodes, Electrons

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Proceedings Article | 9 March 2012 Paper

Spatio-temporal Monte Carlo modeling of a-Se detectors for breast imaging: energy-weighted Swank noise and detective quantum efficiency

Yuan Fang, Andreu Badal, Karim Karim, Aldo Badano

Proceedings Volume 8313, 83135S (2012) https://doi.org/10.1117/12.912012

KEYWORDS: Monte Carlo methods, Quantum efficiency, Sensors, X-rays, X-ray detectors, Breast imaging, Image sensors, Semiconductors, Mammography, Molybdenum

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Proceedings Article | 9 March 2012 Paper

Performance of a prototype 32x32 pixel indirect x-ray imager based on a lateral selenium passive pixel sensor

Rasoul Keshavarzi, Kai Wang, Mohammad Yazdandoost, Kyung-Wook Shin, Feng Chen, Shaikh Hasibul Majid, Shiva Abbaszadeh, Karim Karim

Proceedings Volume 8313, 83135O (2012) https://doi.org/10.1117/12.912286

KEYWORDS: Sensors, Selenium, X-rays, Field programmable gate arrays, X-ray imaging, X-ray detectors, Prototyping, Signal detection, Image quality, Imaging arrays

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Proceedings Article | 9 March 2012 Paper

Novel silicon x-ray detector with TFT readout

Kyung-Wook Shin, Kai Wang, Nicholas Allec, Yuan Fang, Karim Karim

Proceedings Volume 8313, 83135R (2012) https://doi.org/10.1117/12.911359

KEYWORDS: Sensors, Silicon, X-rays, X-ray detectors, Crystallography, Proteins, Interference (communication), Silicon films, Capacitance, Crystals

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Proceedings Article | 3 March 2012 Paper

High performance amorphous selenium lateral photodetector

Shiva Abbaszadeh, Nicholas Allec, Karim Karim

Proceedings Volume 8313, 83135W (2012) https://doi.org/10.1117/12.912287

KEYWORDS: Electrodes, Photodetectors, Sensors, Selenium, Capacitance, X-ray imaging, Absorption, Image sensors, Medical imaging applications, Scintillators

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Proceedings Article | 3 March 2012 Paper

Amorphous selenium photodetector on a flexible substrate for indirect conversion medical imaging

Shiva Abbaszadeh, Shaikh Majid, Nicholas Allec, Karim Karim

Proceedings Volume 8313, 83135X (2012) https://doi.org/10.1117/12.912288

KEYWORDS: Glasses, Selenium, Photodetectors, X-ray imaging, X-rays, Sensors, Medical imaging, Solids, X-ray detectors, Medical imaging applications

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Proceedings Article | 3 March 2012 Paper

Motion artifacts in dual-energy contrast-enhanced mammography

Nicholas Allec, Shiva Abbaszadeh, John Lewin, Karim Karim

Proceedings Volume 8313, 83134P (2012) https://doi.org/10.1117/12.912295

KEYWORDS: Motion models, Systems modeling, Tumors, Spatial frequencies, Mammography, Sensors, Breast, Performance modeling, Motion detection, Linear filtering

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Proceedings Article | 3 March 2012 Paper

Characterization of gated selenium photo detector

Shaikh Hasibul Majid, Kai Wang, Nicholas Allec, Umar Shafique, Karim Karim

Proceedings Volume 8313, 83135U (2012) https://doi.org/10.1117/12.912250

KEYWORDS: Sensors, Selenium, X-rays, Electrodes, Photodetectors, Photoresistors, X-ray detectors, X-ray imaging, Electric field sensors, Blue light emitting diodes

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Proceedings Article | 3 March 2012 Paper

A study of factors limiting spatial resolution using a 25 micron pixel pitch direct-detection amorphous selenium imaging system

Chris Scott, Nicholas Allec, Karim Karim

Proceedings Volume 8313, 83135Y (2012) https://doi.org/10.1117/12.912429

KEYWORDS: Modulation transfer functions, X-rays, Spatial resolution, Photons, Spatial frequencies, Sensors, Mammography, Fluoroscopy, Electrons, Selenium

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Proceedings Article | 5 April 2011 Paper

Aerial image retargeting (AIR): achieving litho-friendly designs

Ayman Yehia Hamouda, James Word, Mohab Anis, Karim Karim

Proceedings Volume 7974, 797411 (2011) https://doi.org/10.1117/12.882073

KEYWORDS: Optical proximity correction, Artificial intelligence, Metals, Resolution enhancement technologies, Model-based design, Photomasks, Lithography, Semiconducting wafers, Electrochemical etching, Optical lithography

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Proceedings Article | 17 March 2011 Paper

Photon quantum shot noise limited array in amorphous silicon technology for protein crystallography applications

Mohammad Yazdandoost, K. Wang, Karim Karim

Proceedings Volume 7961, 79614O (2011) https://doi.org/10.1117/12.878118

KEYWORDS: Proteins, Crystallography, Amorphous silicon, Photonic crystals, Sensors, X-rays, CMOS technology, X-ray detectors, Signal detection, Oscillators

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An array of ring voltage controlled oscillators (RVCO) aiming for photon quantum shot noise limited applications such as protein crystallography is presented. The pixilated array consists of 24 by 21 RVCO pixels. RVCO pixel converts x-ray generated input charge into an output oscillating frequency signal. This architecture can be used in both direct and indirect detection schemes. In this paper the direct detection using a layer of amorphous selenium (a-Se) coupled with the RVCO array is proposed. Theoretical and Experimental results for an in-house fabricated array of RVCOs in amorphous silicon (a-Si) technology are presented. All different requirements for protein crystallography application are listed in this paper and also the way this array addresses each of these requirements is discussed in details in this paper. The off-panel readout circuitry, designed and implemented in-house, is given in this paper. The off-panel readout circuits play an important role in the imaging applications using frequency based pixels. They have to be optimized in order to reduce the fixed pattern noise and fringing effects in an imaging array containing many such RVCO pixels. Since the frequency of oscillation of each of these pixels is in the range of 100 KHz, there is no antenna effect in the array. Antenna effect becomes an important issue in other technologies such as poly silicon (poly-Si) and CMOS technologies due to higher frequency of oscillation ranges (more than 100 MHz). Noise estimations, stability simulations and measurements for some randomly selected pixels in the array for the fabricated RVCO array are presented. The reported architecture is particularly promising for large area photon quantum shot noise applications, specifically protein crystallography. However, this architecture can be used for low dose fluoroscopy, dental computed tomography (CT) and other large area imaging applications limited by input referred electronic noise due to its very low input referred electronic noise, high sensitivity and ease of fabrication in low cost a-Si technology.

Proceedings Article | 17 March 2011 Paper

Lateral organic photodetectors for imaging applications

Umar Shafique, Karim Karim

Proceedings Volume 7961, 796103 (2011) https://doi.org/10.1117/12.878812

KEYWORDS: Sensors, Excitons, Photodetectors, Organic semiconductors, Heterojunctions, Electrons, Absorption, Imaging systems, Absorbance, Electrodes

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Proceedings Article | 17 March 2011 Paper

Study of gain phenomenon in lateral metal-semiconductor-metal detectors for indirect conversion medical imaging

Shiva Abbaszadeh, Nicholas Allec, Kai Wang, Feng Chen, Karim Karim

Proceedings Volume 7961, 79614P (2011) https://doi.org/10.1117/12.877860

KEYWORDS: Selenium, Sensors, External quantum efficiency, Photons, Electrodes, Medical imaging, Quantum efficiency, Measurement devices, Photoresistors, Ionization

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Proceedings Article | 17 March 2011 Paper

Characterization and comparison of lateral amorphous semiconductors with embedded Frisch grid detectors on 0.18um CMOS processed substrate for medical imaging applications

Christos Hristovski, Amir Goldan, Shaikh Hasibul Majid, Kai Wang, Umar Shafique, Karim Karim

Proceedings Volume 7961, 79610Q (2011) https://doi.org/10.1117/12.877708

KEYWORDS: Sensors, Electrodes, External quantum efficiency, Amorphous semiconductors, CMOS sensors, Metals, Capacitance, Photoresistors, Photodetectors, Medical imaging applications

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Proceedings Article | 17 March 2011 Paper

Integration of an amorphous silicon passive pixel sensor array with a lateral amorphous selenium detector for large area indirect conversion x-ray imaging applications

Kai Wang, Mohammad Yazdandoost, Rasoul Keshavarzi, Kyung-Wook Shin, Christos Hristovski, Shiva Abbaszadeh, Feng Chen, Shaikh Hasibul Majid, Karim Karim

Proceedings Volume 7961, 79610V (2011) https://doi.org/10.1117/12.877592

KEYWORDS: Sensors, X-ray imaging, Amorphous silicon, Selenium, Blue light emitting diodes, Thin films, Capacitors, Photodetectors, Cesium, Electrodes

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Proceedings Article | 17 March 2011 Paper

Selenium coated CMOS passive pixel array for medical imaging

Shaikh Hasibul Majid, Amir Goldan, Bahman Hadji, George Belev, Safa Kasap, Karim Karim

Proceedings Volume 7961, 79614L (2011) https://doi.org/10.1117/12.877684

KEYWORDS: Sensors, Selenium, X-rays, CMOS sensors, Transistors, Capacitors, Amplifiers, CMOS technology, X-ray detectors, Imaging arrays

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Proceedings Article | 16 March 2011 Paper

Analysis of multilayer and single layer X-ray detectors for contrast-enhanced mammography using imaging task

Nicholas Allec, Shiva Abbaszadeh, Karim Karim

Proceedings Volume 7961, 796111 (2011) https://doi.org/10.1117/12.877854

KEYWORDS: Sensors, Photons, Mammography, Interference (communication), Breast, Tumors, Dual energy imaging, Signal detection, Systems modeling, Selenium

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