A fine-grained silicon detector for high-energy gamma-ray astrophysics

We propose a silicon telescope to be placed in a satellite for the search of gamma-ray sources in the energy range between 25 MeV and 100 GeV. The proposed experiment will have an area of 2500 cm(2), an energy resolution ranging from 7% to 8% and an angular resolution from 0.2 and 0.1 degrees between 1 GeV and 10 GeV. The telescope is based on the use of silicon strip detectors. Together with the energy measurement, a calorimeter of this type allows the determination of. the particle type and its al rival direction, through the analysis of the spatial and energetic distribution of the electromagnetic shower produced. Detectors based on silicon technology have many advantages for space applications: no gas refilling: system or high voltages, no need of photomultipliers (low consumption), short dead time, possibility of self-triggering. The GILDA project has been designed having in mind the weight limitation of 400 kg required by the Resource-01 satellite and it is carried out in the framework of the RIM (Russian Italian Mission) program. The launch is foreseen for the beginning of the next century.