A monolithic array of silicon drift detectors for high-resolution gamma-ray imaging

In this work we present a detection module for high-resolution gamma-ray imaging based on a monolithic array of Silicon Drift Detectors (SDDs) coupled to a single CsI(Tl) scintillator. Each SDD of the array has the front-end JFET directly integrated on the detector chip close to the collecting anode. The very low electronics noise obtainable with these devices allows to reach sub-millimeter position resolution and good energy resolution with a gamma-ray imager based on a single scintillator crystal coupled to the SDD array. The detector module here presented is the evolution of a previous prototype based on a very limited numbers of SDDs. This module is based on a monolithic array of 19 hexagonal SDD and has about 1 cm/sup 2/ of total sensitive area. A new multi-channel integrated electronics package has been developed for the readout of the signals from the detector. The results of the experimental characterisation of the array and on the gamma-ray detector module are presented.