Monte Carlo Transport Methods for Semiconductor X-ray Imaging Detectors

dc.comment.hiddenPatent and publication pending Confidential defense was granteden
dc.contributor.authorFang, Yuan
dc.date.accessioned2013-07-17T20:05:10Z
dc.date.available2015-07-08T05:30:11Z
dc.date.issued2013-07-17T20:05:10Z
dc.date.submitted2013
dc.description.abstractThis thesis describes the development of a novel comprehensive Monte Carlo simulation code, ARTEMIS, for the investigation of electron-hole pair transport mechanisms in a-Se x-ray imaging detectors. ARTEMIS allows for modeling of spatiotemporal carrier transport in a-Se, combining an existing Monte Carlo simulation package, PENELOPE, for simulation of x-ray and secondary electron interactions and new routines for electron-hole pair transport with three-dimensional spatiotemporal signal output considering the effects of applied electric field. The detector Swank factor, an important imaging performance metric is calculated from simulated pulse-height spectra and shown to depend on incident x-ray energy and applied electric field. Simulation results are compared to experimental measurements and are found to agree within 2%. Clinical x-ray spectra are also used to study detector performance in terms of energy weighting and electronic noise. Simulation results show energy-weighting effects are taken into account in the ARTEMIS model, where the Swank factor and DQE have a higher dependence on the high-energy incident x rays due to increased carrier yield. Electronic noise is found to widen the pulse-height spectra and degrade the Swank factor. The effect of recombination algorithms and burst models are studied. A comparison of a first-hit algorithm and a nearest-neighbor approach shows no significant difference in the simulation output while achieving reduced simulation time. The examination of the initial generation of carriers in the burst shows that the recombination efficiency of carriers is dependent on the carrier density and electric field. Finally, the spatial resolution characteristics of a flat-panel a-Se detector are studied by using the ARTEMIS model for spatial output and image generation. The modulation transfer functions are calculated from simulated detector point response functions for monoenergetic and clinical radiation qualities.en
dc.description.embargoterms1 yearen
dc.identifier.urihttp://hdl.handle.net/10012/7650
dc.language.isoenen
dc.pendingtrueen
dc.publisherUniversity of Waterlooen
dc.subjectMonte Carloen
dc.subjectX-ray Detectoren
dc.subject.programElectrical and Computer Engineeringen
dc.titleMonte Carlo Transport Methods for Semiconductor X-ray Imaging Detectorsen
dc.typeDoctoral Thesisen
uws-etd.degreeDoctor of Philosophyen
uws-etd.degree.departmentElectrical and Computer Engineeringen
uws.peerReviewStatusUnrevieweden
uws.scholarLevelGraduateen
uws.typeOfResourceTexten

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