Characterizations of the charge sharing and loss effects on Cadmium Telluride and Cadmium Zinc Telluride pixel detectors with a custom ASIC for astrophysical applications

We are developing imaging Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CZT) pixel detectors with potential applications in hard X-ray astrophysical NASA Explorer and Probe-class missions, utilizing wide field and focusing instruments. Our hybrid sensor consists of a CdTe and a CZT detector with segmented anode contacts directly bonded to an ASIC. We have utilized a custom low-noise, low-power ASIC developed for NuSTAR mission. While NuSTAR employed eV Products CZT detectors, for this study, we used a CdTe detector by Acrorad and a CZT detector by Redlen. Both detectors have anode pixels with a 604-micron pitch in a 32 x 32 array. The CdTe detectors have segmented Schottky blocking contacts, whereas the CZT detectors have plain contacts. Understanding the charge sharing and charge loss behavior between the pixels is crucial to achieve good energy resolutions. In this paper, we report on the study of charge sharing and charge loss effects between the pixels. We will compare the behavior among eV CZT, Redlen CZT, and Acrorad CdTe detectors. Furthermore, we will discuss how these effects might influence smaller pixel pitch detectors for our next-generation prototype ASIC.