Optimization of <= 200 um pitch CZT detectors for future high-resolution X-ray instrumentation in astrophysics

TL;DR

This paper discusses optimizing small-pixel CZT and CdTe detectors with pitches <= 200 um to meet the demanding spatial, spectral, and energy resolution requirements of future high-resolution X-ray astrophysics missions.

Contribution

It presents R&D efforts to improve small-pixel CZT and CdTe detectors for next-generation X-ray telescopes with high angular resolution.

Findings

Achieved detector pixel pitches of <= 200 um.

Enhanced energy resolution and low energy thresholds.

Improved detector uniformity and charge collection efficiency.

Abstract

Cadmium Zinc Telluride and Cadmium Telluride are the detector materials of choice for the detection of X-rays in the X-ray energy band E >= 5keV with excellent spatial and spectral resolution and without cryogenic cooling. Owing to recent breakthroughs in grazing incidence mirror technology, next-generation hard X-ray telescopes will achieve angular resolution between 5 and 10 arc seconds - about an order of magnitude better than that of the NuSTAR hard X-ray telescope. As a consequence, the next generation of X-ray telescopes will require pixelated X-ray detectors with pixels on a grid with a lattice constant of <= 250um. Additional detector requirements include a low energy threshold of less than 5keV and an energy resolution of less than one keV. The science drivers for a high angular-resolution X-ray mission include studies and measurements of black hole spins, the cosmic evolution of super-massive black holes, active galactic nuclei feedback, and the behaviour of matter at very high densities. In this contribution, we report on our R&D studies with the goal to optimise small-pixel Cadmium Zinc Telluride and Cadmium Telluride detectors.