An 8-channels analog ASIC for a gamma-ray burst detector based on silicon drift detector and scintillator

We have developed an 8-channel analog readout ASIC for gamma-ray burst (GRB) detector combining the silicon drift detector (SDD) array and BGO scintillators. The ASIC is designed on the basis of the Open-IP LSI project by JAXA and implemented with TSMC 0.35 mum CMOS technology. The ASIC is composed of 8-channel analog circuit, each of which includes a preamplifier, shaping amplifiers and peak-hold circuit. The shaping amplifiers are composed of a fast-shaper (0.5 mus) and a slow-shaper (3 mus) for event discrimination by double integration method. The ASIC achieved the input noise performance of 13.8 muV (fast) and 14.7 muV (slow), which correspond to threshold energy of 0.4 keV in the SDD event or 25 keV in the BGO event. As a result of primary measurement with a SDD, we could confirm signals of Mn-Kalpha line.