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.Peer Reviewe
