Mr. Marc Hansroul Profile

Marc Hansroul

Image Chain Manager at Analogic Canada Corp

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Publications (7)

Proceedings Article | 18 March 2008 Paper

Modeling of dark current and ghosting in multilayer amorphous selenium x-ray detectors

M. Kabir, F. Manouchehri, S. Mahmood, V. Devabhaktuni, O. Tousignant, H. Mani, J. Greenspan, P. Botka

Proceedings Volume 6913, 69133U (2008) https://doi.org/10.1117/12.770697

KEYWORDS: X-rays, Sensors, X-ray detectors, Electrons, Data modeling, Photoresistors, X-ray imaging, Metals, Electric field sensors, Electrodes

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A theoretical model for describing the bias-dependent transient behavior of dark current in multilayer amorphous selenium (a-Se) detectors has been developed by solving the trapping rate equations and Poisson's equation in the a-Se layer. The transient dark currents in these detectors are measured and the proposed dark model is compared with the measured data. The model shows a very good agreement with the experimental results. It has been found that the dark current is mainly controlled by the Schottky emission of holes from the metal/a-Se contact. The space charge build-up due to the hole injection and trapping in the blocking layer reduces the internal field at the metal/a-Se interface of positive side and thus the dark current eventually is limited by the space charge. It has been found that the electric fields at the metal contacts reduce to 20-30% of the applied field (applied voltage/thickness). The comparison of the model with the experimental data estimates some important properties (e.g., trap center concentrations, space charges, and effective barrier heights) of the blocking layers of the multilayer detectors. The dependence of the X-ray sensitivity of multilayer a-Se X-ray imaging detectors on repeated X-ray exposures is studied by considering accumulated trapped charges and their effects (trap filling, recombination, electric field profile, electric field dependent electron-hole pair creation), the carrier transport in the blocking layers, X-ray induced metastable deep trap center generations, and the effects of dark current. We simultaneously solve the continuity equations for both holes and electrons, trapping rate equations, and the Poisson's equation across the photoconductor for a step X-ray exposure by the Backward Euler finite difference method. The theoretical model shows a very good agreement with the experimental relative sensitivity versus cumulative X-ray exposure characteristics. The electric field distribution across the multilayer detector and the dark current density under repeated exposures are also estimated.

Proceedings Article | 20 April 2005 Paper

Digital breast tomosynthesis using an amorphous selenium flat panel detector

M. Bissonnette, M. Hansroul, E. Masson, S. Savard, S. Cadieux, P. Warmoes, D. Gravel, J. Agopyan, B. Polischuk, W. Haerer, T. Mertelmeier, J. Lo, Y. Chen, J. Dobbins, J. Jesneck, S. Singh

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.601622

KEYWORDS: Sensors, Modulation transfer functions, Breast, Image quality, X-rays, Selenium, Prototyping, Data acquisition, Reconstruction algorithms, X-ray detectors

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Proceedings Article | 6 May 2004 Paper

Ghosting comparison for large-area selenium detectors suitable for mammography and general radiography

Vincent Loustauneau, Michel Bissonnette, Sebastien Cadieux, Marc Hansroul, Eric Masson, Serge Savard, Brad Polischuk

Proceedings Volume 5368, (2004) https://doi.org/10.1117/12.535812

KEYWORDS: Sensors, Selenium, Mammography, X-rays, Digital filtering, Radiography, Image sensors, X-ray detectors, X-ray imaging, Silicon

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Proceedings Article | 5 June 2003 Paper

Imaging performance of a clinical selenium flat-panel detector for advanced applications in full-field digital mammography

Vincent Loustauneau, Michel Bissonnette, Sebastien Cadieux, Marc Hansroul, E. Masson, Serge Savard, Brad Polischuk, Mari Lehtimauki

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.484075

KEYWORDS: Sensors, Selenium, Breast, Modulation transfer functions, X-rays, Digital mammography, Image quality, Mammography, Tissues, Imaging systems

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Proceedings Article | 28 June 2001 Paper

Se-based flat-panel detector for screening mammography

Brad Polischuk, Serge Savard, Vincent Loustaneau, Marc Hansroul, Sebastien Cadieux, Anne Vaque

Proceedings Volume 4320, (2001) https://doi.org/10.1117/12.430884

KEYWORDS: Sensors, Modulation transfer functions, Selenium, Mammography, X-rays, Signal to noise ratio, Photons, Prototyping, Digital mammography, Image resolution

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Proceedings Article | 25 April 2000 Paper

Quantitative analysis of performance of selenium flat-panel detector for interventional mammography

Anne Debrie, Brad Polischuk, Henri Rougeot, Marc Hansroul, Eric Poliquin, Mario Caron, Kerwin Wong, Ziad Shukri, Jean-Pierre Martin

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384540

KEYWORDS: Sensors, Image quality, Selenium, Digital mammography, Digital imaging, Modulation transfer functions, Signal to noise ratio, Quantum efficiency, X-rays, Mammography

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Proceedings Article | 28 May 1999 Paper

Direct conversion detector for digital mammography

Brad Polischuk, Henri Rougeot, Kerwin Wong, Anne Debrie, Eric Poliquin, Marc Hansroul, Jean-Pierre Martin, Tri-Tue Truong, Martin Choquette, Luc Laperriere, Ziad Shukri

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349518

KEYWORDS: Sensors, Selenium, X-rays, Modulation transfer functions, Digital mammography, Absorption, Mammography, Electronics, Signal to noise ratio, Prototyping

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Showing 5 of 7 publications

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