Study of Thick CZT Detectors for X-ray and Gamma-ray Astronomy

Journal Article · Sat Feb 12 04:00:00 EST 2011 · Astroparticle Physics

DOI:https://doi.org/10.1016/j.astropartphys.2011.01.013· OSTI ID:1049209

Li, Q; De, Geronimo G; Beilicke, M; Lee, K; Garson, III, A; Guo, Q; Martin, J; Yin, Y; Dowkontt, P; Jung, I; Krawczynski, H

CdZnTe (CZT) is a wide bandgap II-VI semiconductor developed for the spectroscopic detection of X-rays and {gamma}-rays at room temperature. The Swift Burst Alert Telescope is using an 5240 cm{sup 2} array of 2 mm thick CZT detectors for the detection of 15-150 keV X-rays from Gamma-ray Bursts. We report on the systematic tests of thicker (0.5 cm) CZT detectors with volumes between 2 cm{sup 3} and 4 cm{sup 3} which are potential detector choices for a number of future X-ray telescopes that operate in the 10 keV to a few MeV energy range. The detectors contacted in our laboratory achieve Full Width Half Maximum energy resolutions of 2.7 keV (4.5%) at 59 keV, 3 keV (2.5%) at 122 keV and 4 keV (0.6%) at 662 keV. The 59 keV and 122 keV energy resolutions are among the world-best results for 0.5 cm thick CZT detectors. We use the data set to study trends of how the energy resolution depends on the detector thickness and on the pixel pitch. Unfortunately, we do not find clear trends, indicating that even for the extremely good energy resolutions reported here, the achievable energy resolutions are largely determined by the properties of individual crystals. Somewhat surprisingly, we achieve the reported results without applying a correction of the anode signals for the depth of the interaction. Measuring the interaction depths thus does not seem to be a pre-requisite for achieving sub-1% energy resolutions at 662 keV.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1049209
• Report Number(s): BNL--95316-2011-JA; KA-04-04
• Journal Information: Astroparticle Physics, Journal Name: Astroparticle Physics Journal Issue: 10 Vol. 34; ISSN 0927-6505
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ANODES
ASTRONOMY
DETECTION
ENERGY RANGE
ENERGY RESOLUTION
TELESCOPES
THICKNESS