Development and in orbit testing of an X ray detector within a 2U CubeSat

A CdZnTe based semiconductor X-ray detector (XRD) and its associated readout electronics is developed by the Space Systems Design Laboratory of Istanbul Technical University and High Energy Astrophysics Detector Laboratory of Sabanci University along with an SME partner. The detector will utilize 30 orthogonal cross strip electrodes (and 3 steering electrodes in between anodes) whose geometry is optimized by an extensive set of simulations and energy resolution measurements. The signals will be read by RENA 3b ASIC controlled by MSP 430 microcontroller. The system will have its own battery and will be turned on intermittently due to power constraints. CdZnTe based X-ray detectors have been utilized in space, but they are either pixelated (NuStar), or they consist of many individual crystal pieces (BAT in Swift satellite). The aim of the XRD is to show that large volume crystals with orthogonal strips are viable alternatives, especially for small satellite systems with medium energy resolution requirement. XRD will also characterize the hard X-ray background in 20-200 keV at low Earth orbit conditions as a function of altitude. Due to power and telemetry constraints, the individual events will be corrected for hole trapping on-board, histogrammed, and only the X-ray spectra will be transmitted to the ground station along with a small set of raw data for diagnostic purposes. The XRD is planned to travel into space, as a secondary science mission, on board BeEagleSat which is a 2U CubeSat developed as one of the possible double (2U) CubeSats for the QB50 project. QB50 is a European Framework 7 (FP7) project carried out by a number of international organizations led by the von Karman Institute of Belgium. Its main scientific objective is to study in situ the temporal and spatial variations of a number of key constituents and parameters in the lower thermosphere with a network of about 50 double and triple CubeSats, separated by few hundred kilometers and carrying a determined set of sensors.