Analytical model of single-X-ray photon counting pixel-array detectors

Marchal, J.; McGrath, John; Medjoubi, Kadda

doi:10.1088/1748-0221/9/03/c03006

Cited by 3 publications

(2 citation statements)

References 16 publications

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“…For example, it cannot distinguish K fluorescent photons whether they originate from Cd or Te. Therefore, a more detailed and systematic model describing cascaded x-ray interactions is required [21,24].…”

Section: Discussionmentioning

confidence: 99%

X-ray interaction characteristic functions in semiconductor detectors

et al. 2020

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A: Secondary photons produced by x-ray interactions, such as scattered and fluorescent x-rays, can degrade the performance of semiconductor imaging detectors. In this article, we define characteristic functions describing the spatial-frequency-dependent absorbed energy and counting spectra for energy-integrating and single-photon counting detectors, respectively. We describe the characteristic function as a sum of contributions due to several x-ray interaction mechanisms. To obtain the characteristic function of a detector, we performed list-mode analysis on the Monte Carlo simulation results obtained for an impulsive x-ray excitation, hence discriminating x-ray interactions depositing energies over space. We apply this analysis to cadmium telluride detectors for wide ranges of energy and detector designs. The shape of characteristic functions is mostly governed by fluorescent x-ray interactions rather than scattered photons. The effects of x-ray energy, detector pitch, and threshold energy on the characteristic functions of single-photon counting are discussed. K: Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Interaction of radiation with matter; Models and simulations 1Corresponding author.

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Section: Discussionmentioning

confidence: 99%

X-ray interaction characteristic functions in semiconductor detectors

et al. 2020

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“…However, in the case of a photon counter, there is no threshold value at which all photons could be assigned to a unique pixel. If the threshold is set at half of the X-ray energy, the counting efficiency at the pixel corners will be reduced [17]. This sets a limit of the minimum pixel pitch for SPC detectors at about 40-50 µm to maintain better than 90 % efficiency.…”

Section: Observation Of Charge Sharingmentioning

confidence: 99%

Looking at single photons using hybrid detectors

et al. 2015

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The SLS detector group develops silicon hybrid detectors for X-ray applications used in synchrotron facilities all over the world. Both microstrip and pixel detectors with either single photon counting or charge integrating read out are being developed.Low noise charge integrating detectors can be operated in single photon regime, i.e. with low fluxes and high frame rates in order to detect on average less than one photon per cluster of 2×2 pixels. In this case, the analog signal read out for each single X-ray provides information about the energy of the photon. Moreover the signal from neighboring channels can be correlated in order to overcome or even take advantage of charge sharing.The linear charge collection model describing microstrip detectors and large pixels is unsuitable for the calibration of small pitch pixel detectors due to the large amount of charge sharing occurring also in the corner region.For this reason, the linear charge collection model is extended to the case of small pixels and tested with monochromatic X-ray data acquired using the 25 µm pitch M ÖNCH and the 75 µm pitch JUNGFRAU detectors.The successful outcome of the calibration of the M ÖNCH detector is proven by the high energy resolution of the spectrum obtained by accumulating the counts from more than 6000 channels after the correction of the gain mismatches using the proposed model.

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