Characterization of a CdZnTe detector for a low-power CubeSat application

Abstract

We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for the MeVCube project: a small Compton telescope on a CubeSat platform. MeVCube is expected to cover the energy range between 200 keV and 4 MeV, with a sensitivity comparable to the one of the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a 3-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed by Ideas, with a power consumption of only 0.25 mW/channel, which exhibits good performance in terms of dynamic range, noise and linearity. A 2.0 cm× 2.0 cm× 1.5 cm CdZnTe detector, with a custom 8 × 8 pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discrete Amptek A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around 3% FWHM has been measured at a gamma energy of 662 keV; at 200 keV the average energy resolution is 6.5%, decreasing to ≲ 2% at energies above 1 MeV. A 3-D spatial resolution of ≈ 2 mm is achieved in each dimension.

Evaluation of the performance of a CdZnTe-based soft gamma-ray detector for CubeSat payloads

“…This comparison study is an effort to compare the simulated performance of the new detector design with the old design, although direct comparison is not possible due to technical limitations. The CZT crystal readout for the new design is obtained using (11 × 11) pixels over the old readout design of (8 × 8) pixels (Lucchetta et al, 2022a, see Figure 1). In the old payload design simulations (Lucchetta et al, 2022b, see Figure 2), the CZT crystals are placed in a tight packing, whereas in the new design, CZT crystals are placed with an offset of 12 mm (see Figure 2 here).…”

“…While Lucchetta et al (2022b) explores simulations of payload designs using numerous CZT crystals, it only presents lab tests for a single CZT crystal detector, as detailed in Lucchetta et al (2022a). Moreover, there is no existing report on detector designs employing multiple (VATA450.3) motherboards.…”

Development of travelling heater method for growth of detector grade CdZnTe single crystals

“…Cadmium zinc telluride (CdZnTe) is one of the most promising room-temperature semiconductor gamma radiation detector material due to its wide energy band gap and high atomic number [1][2][3][4]. The research activities carried out on detector technology over the past few decades have showcased that CdZnTe is an excellent substitute for scintillation detectors in terms of high sensitivity, better energy resolution and high spatial resolution at room temperature [4][5][6][7]. In the recent past, CdZnTe detector with an energy resolution of less than ≈ 0.5 % at 662 keV of 137 Cs had already been demonstrated [7] and commercial detectors are also available in the market.…”