A monolithic array of Silicon Drift Detectors for high-resolution gamma ray imaging

In this work, the preliminary results obtained with a high position resolution gamma-ray imaging detector are presented. The detector consists of a single CsI(Tl) scintillator crystal optically coupled to a monolithic array of 19 silicon drift detectors (SDDs) used as photodetectors. In this array, having a total sensitive area of about 1 cm2, each SDD has a front-end JFET directly integrted on the detector chip, close to the connecting anode. This architecture reduces the electronic noise of each single photodetector to a value small enough to obtain a submillimiter position resolution at 122 keV gamma ray energy. The present detector module represents the development of a previuos prototype based on a very limited number of SDDs.