The Ibis-Picsit detector onboard Integral

PICsIT is the high-energy detector layer of the IBIS Imager, composed of 4096 CsI(Tl) scintillator detectors 8.4 * 8.4*300 mm in size with PhotoDiode readout. The detector operates in the 175 keV-20.4 MeV range and its data generation modes make it possible to collect information from single events and multiple coincident events. PICsIT is surrounded by the active BGO VETO and is located about 3 metres below the coded mask. The entire PICsIT plane is physically divided into 8 modules and logically divided into smaller units. The overall performance of the plane is directly related to the behaviour of each individual pixel, including its electronics, the system interconnection logic, and interaction with the other sub-systems. Pixels and electronic parameters were monitored constantly during instrument assembly. The following report describes PICsIT design and contains a summary of on-ground test results.