Use of high-granularity CdZnTe pixelated detectors to correct response non-uniformities caused by defects in crystals

Journal Article · Sun Sep 06 00:00:00 EDT 2015 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI:https://doi.org/10.1016/j.nima.2015.08.051· OSTI ID:1326734

Bolotnikov, A. E. ^[1]; Camarda, G. S. ^[1]; Cui, Y. ^[1]; De Geronimo, G. ^[1]; Eger, J. ^[2]; Emerick, A. ^[2]; Fried, J. ^[1]; Hossain, A. ^[1]; Roy, U. ^[1]; Salwen, C. ^[1]; Soldner, S. ^[2]; Vernon, E. ^[1]; Yang, G. ^[1]; James, R. B. ^[1]

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1. Brookhaven National Lab. (BNL), Upton, NY (United States)
2. eV Products, Inc., Saxonburg, PA (United States)

Following our successful demonstration of the position-sensitive virtual Frisch-grid detectors, we investigated the feasibility of using high-granularity position sensing to correct response non-uniformities caused by the crystal defects in CdZnTe (CZT) pixelated detectors. The development of high-granularity detectors able to correct response non-uniformities on a scale comparable to the size of electron clouds opens the opportunity of using unselected off-the-shelf CZT material, whilst still assuring high spectral resolution for the majority of the detectors fabricated from an ingot. Here, we present the results from testing 3D position-sensitive 15×15×10 mm³ pixelated detectors, fabricated with conventional pixel patterns with progressively smaller pixel sizes: 1.4, 0.8, and 0.5 mm. We employed the readout system based on the H3D front-end multi-channel ASIC developed by BNL's Instrumentation Division in collaboration with the University of Michigan. We use the sharing of electron clouds among several adjacent pixels to measure locations of interaction points with sub-pixel resolution. By using the detectors with small-pixel sizes and a high probability of the charge-sharing events, we were able to improve their spectral resolutions in comparison to the baseline levels, measured for the 1.4-mm pixel size detectors with small fractions of charge-sharing events. These results demonstrate that further enhancement of the performance of CZT pixelated detectors and reduction of costs are possible by using high spatial-resolution position information of interaction points to correct the small-scale response non-uniformities caused by crystal defects present in most devices.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Nonproliferation and Verification Research and Development (NA-22); USDOE
• Grant/Contract Number: SC00112704
• OSTI ID: 1326734
• Alternate ID(s): OSTI ID: 1359620
• Report Number(s): BNL-111801-2016-JA; R&D Project: 21542; NN200100
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 805, Issue C; ISSN 0168-9002
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CdZnTe
high-granularity detectors
3D pixelated detectors
crystal defects
charge sharing
charge-loss correction