Performance of pixelated CZT detectors as a function of pixel and steering grid layout

Beilicke, M.; Geronimo, G. De; Dowkontt, P. F.; Garson, A.; Guo, Q.; Lee, K.; Martin, J.; Krawczynski, H.

doi:10.1016/j.nima.2013.01.016

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…efficiency of CdZnTe detectors, as reported, e.g., in [15]. When the steering grid is biased to a slightly negative voltage with respect to the grounded pixels (around −50 V, see also appendix B), electrons are forced to move towards the pixels when approaching the anode surface, reducing charge loss in the pixels gap.…”

Section: Jinst 17 P08004supporting

confidence: 59%

“…In pixelated CdZnTe detectors, charge sharing causes charge loss for events occurring in the gap between pixels, and is one of the factors that degrades the performance of the detector. The presence of a steering grid, surrounding the anode pixel and biased to a slightly negative voltage with respect to the grounded pixels, has shown to improve the performance of CdZnTe detectors [15,20]: when the steering grid is biased to a slightly negative voltage, electrons are forced to move towards the pixels when approaching the anode surface, reducing charge loss in the pixels gap. Typical values for the steering grid voltage are ∼ −50 V [15]: lower values do not lead to significant improvements in collection efficiency, while higher values result in an additional surface current and increased noise.…”

Section: B Steering Grid Measurementsmentioning

confidence: 99%

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Characterization of a CdZnTe detector for a low-power CubeSat application

et al. 2022

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We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for the MeVCube project: a small Compton telescope on a CubeSat platform. MeVCube is expected to cover the energy range between 200 keV and 4 MeV, with a sensitivity comparable to the one of the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a 3-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed by Ideas, with a power consumption of only 0.25 mW/channel, which exhibits good performance in terms of dynamic range, noise and linearity. A 2.0 cm× 2.0 cm× 1.5 cm CdZnTe detector, with a custom 8 × 8 pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discrete Amptek A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around 3% FWHM has been measured at a gamma energy of 662 keV; at 200 keV the average energy resolution is 6.5%, decreasing to ≲ 2% at energies above 1 MeV. A 3-D spatial resolution of ≈ 2 mm is achieved in each dimension.

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Section: Jinst 17 P08004supporting

confidence: 59%

Section: B Steering Grid Measurementsmentioning

confidence: 99%

Characterization of a CdZnTe detector for a low-power CubeSat application

et al. 2022

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“…The presence of a steering electrode has shown to improve the charge collection efficiency of CdZnTe detectors, as reported, e.g., in Ref. 13. When the steering grid is biased to a slightly negative voltage with respect to the grounded pixels (around −50 V), electrons are forced to move towards the pixels when approaching the anode surface, reducing charge loss in the pixels gap.…”

Section: Introductionmentioning

confidence: 66%

“…In pixelated CdZnTe detectors, charge sharing causes charge loss for events occurring in the gap between pixels, and is one of the factors that degrades the performance of the detector. The presence of a steering grid, surrounding the anode pixel and biased to a slightly negative voltage with respect to the grounded pixels, has shown to improve the performance of CdZnTe detectors [13,17]: when the steering grid is biased to a slightly negative voltage, electrons are forced to move towards the pixels when approaching the anode surface, reducing charge loss in the pixels gap. The performance degradation due to charge sharing effect, may vary according to several factors of the considered device, such as pixel size, width of the gap between pixels, size of the steering grid, as well as shaping performance and noise of the read-out electronics.…”

Section: B Steering Grid Measurementsmentioning

confidence: 99%

Characterization of a CdZnTe detector for a low-power CubeSat application

Lucchetta,

Ackermann,

Berge

et al. 2022

Preprint

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We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for the MeVCube project: a small Compton telescope on a CubeSat platform. MeVCube is expected to cover the energy range between 200 keV and 4 MeV, with performance comparable to the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a 3-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed by Ideas, with a power consumption of only 0.25 mW/channel, which exhibits good performance in terms of dynamic range, noise and linearity. A 2.0 cm × 2.0 cm × 1.5 cm CdZnTe detector, with a custom 8 × 8 pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discrete Amptek A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around 3% FWHM has been measured at a gamma energy of 662 keV; at 200 keV the average energy resolution is 6.5%, decreasing to 2% at energies above 1 MeV. A 3-D spatial resolution of ≈ 2 mm is achieved.

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“…The interested reader may consult (Iniewski et al, 2007;Rana et al, 2009;Kitaguchi et al, 2011;Yin et al, 2011Yin et al, , 2013Yin et al, , 2014Veale et al, 2014;Montémont et al, 2014;Ocampo Giraldo et al, 2018;Khalil et al, 2018) for discussions of charge sharing in CZT detectors, and (Zhang et al, 2004;Benoit and Hamel, 2009;De Geronimo et al, 2008;Kim et al, 2011;Zhang et al, 2012;Beilicke et al, 2013;Yin et al, 2014;Kim et al, 2014;Wahl et al, 2015;Chen et al, 2018) for discussion of CZT detectors of different thicknesses and pixel sizes.…”

Section: Discussionmentioning

confidence: 99%

Cadmium Zinc Telluride Detectors for a Next-Generation Hard X-ray Telescope

Tang,

Kislat,

Krawczynski

2021

Preprint

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We are currently developing Cadmium Zinc Telluride (CZT) detectors for a next-generation space-borne hard X-ray telescope which can follow up on the highly successful NuSTAR (Nuclear Spectroscopic Telescope Array) mission. Since the launch of NuSTAR in 2012, there have been major advances in the area of X-ray mirrors, and state-of-the-art X-ray mirrors can improve on NuSTAR's angular resolution of ∼1 arcmin Half Power Diameter (HPD) to 15 or even 5 HPD. Consequently, the size of the detector pixels must be reduced to match this resolution. This paper presents detailed simulations of relatively thin (1 mm thick) CZT detectors with hexagonal pixels at a next-neighbor distance of 150 µm. The simulations account for the non-negligible spatial extent of the deposition of the energy of the incident photon, and include detailed modeling of the spreading of the free charge carriers as they move toward the detector electrodes. We discuss methods to reconstruct the energies of the incident photons, and the locations where the photons hit the detector. We show that the charge recorded in the brightest pixel and six adjacent pixels suffices to obtain excellent energy and spatial resolutions. The simulation results are being used to guide the design of a hybrid application-specific integrated circuit (ASIC)-CZT detector package.

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Performance of pixelated CZT detectors as a function of pixel and steering grid layout

Cited by 7 publications

References 18 publications

Characterization of a CdZnTe detector for a low-power CubeSat application

Characterization of a CdZnTe detector for a low-power CubeSat application

Characterization of a CdZnTe detector for a low-power CubeSat application

Cadmium Zinc Telluride Detectors for a Next-Generation Hard X-ray Telescope

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