ICARUS ASIC: a 16 channel photodiode read out system

In the framework of the INTEGRAL satellite, the second medium size mission of the ESA Horizon 2000 plus plan, it is required that the gamma ray detector of IBIS, one of the main on board instruments, exhibits position sensitive capabilities. This detector will be realised in two different planes covering different energy ranges. Although constructed with different technologies (Solid State and Scintillator detectors), both layers will be assembled using arrays of independent detectors (pixels) whose size will determine the spatial resolution of the instrument. In this approach each pixel needs its individual electronic chain able to process the charge delivered via a low noise charge amp and a shaping stage. Each chain will be completed with a trigger discriminator and peak and hold stage that will maintain the signal amplitude information locally for successive read out. To fulfil the constraints of space and power available for the project, these electronic chains can only be realised using ASIC technology. In this work the ICARUS ASIC used to read-out the signals delivered by PhotoDiodes (PD) employed in the high energy plane of the IBIS instrument is described and the first performance evaluation reported.