Prototype Imaging Cd-Zn-Te Array Detector

TL;DR

This paper reports on the development and testing of a thick, pixellated Cd-Zn-Te detector array for high-energy astrophysical imaging, achieving around 4% energy resolution at 60 keV.

Contribution

The paper introduces a novel thick CZT detector with a pixellated readout and demonstrates its initial performance for astrophysical applications.

Findings

Achieved ~4% energy resolution at 60 keV

Developed a prototype detector with 10x10x5 mm CZT and 4x4 pixel readout

Designed a full imaging detector array for future use

Abstract

We describe initial results of our program to develop and test Cd-Zn-Te (CZT) detectors with a pixellated array readout. Our primary interest is in the development of relatively thick CZT detectors for use in astrophysical coded aperture telescopes with response extending over the energy range $\sim 10-600$ keV. The coded aperture imaging configuration requires only relatively large area pixels (1-3 mm), whereas the desired high energy response requires detector thicknesses of at least 3-5 mm. We have developed a prototype detector employing a 10 x 10 x 5 mm CZT substrate and 4 x 4 pixel (1.5 mm each) readout with gold metal contacts for the pixels and continuous gold contact for the bias on the opposite detector face. This MSM contact configuration was fabricated by RMD and tested at Harvard for uniformity, efficiency and spatial as well as spectral resolution. We have developed an ASIC readout (IDE-VA-1) and analysis system and report results, including $\sim 4$% (FWHM) energy resolution at 60 keV. A prototype design for a full imaging detector array is discussed.