Development of a detector based on Silicon Drift Detectors and 2″ lanthanum bromide scintillator for gamma-ray spectroscopy

This work deals with the development of a new gamma detector based on Silicon Drift Detectors (SDDs) to read out large (2" up to 3") LaBr₃:Ce scintillators for gamma-ray spectroscopy for astronomy applications, an activity supported by ESA. SDDs, characterized by high quantum efficiency and low electronic noise, are good candidates in such applications with a wide energy range of gamma rays to be detected from 150 keV to 15 MeV. The gamma-ray detection system here presented is composed of a 2"×2" LaBr₃:Ce scintillator coupled with four SDD modules arranged in a 2×2 format (a total of 36 SDDs). An energy resolution of 3.5% FWHM at 662 keV has been achieved with this detection system being read out by custom developed electronics. In this work we will report on the SDD technology used, their X-ray characterization, readout electronics, experimental setups and gamma-ray spectroscopy results.