CZT based spectrometers for environmental radiation measurements

Abstract The Balloon-borne Instrument for Spectral Scanning of high-altitude Environments (BISSE) is a lightweight gamma-ray measurement system designed as a payload of standard weather balloons which can be retrieved after the flight. Its design enables multiple flights at a relatively low cost. The BISSE system automatically records radiation spectra at different altitudes throughout the flight. The sensor is cadmium zinc telluride (CZT) with a crystal volume of 1 cm 3 , providing good spectral resolution while maintaining low weight. The system also includes various auxiliary sensors that enable additional measurements during the flight, such as temperature and pressure monitoring. The Light-weight Aranda-borne Gamma-ray and Environmental Radiation detector (LAGER) is a modification of the BISSE system for underwater measurements. In contrast to the BISSE, the primary limitation for the design is overall size rather than weight; consequently the system is more compact. In this contribution, we discuss the designs of BISSE and LAGER as well as the latest improvements to both systems. The BISSE system is also investigated as a payload for a rotary-wing unmanned aerial vehicle. These flights motivated several crucial modifications to the system for future deployments. Planned balloon flight is also studied using Geant4 simulations.