A VLSI charge preamplifier for particle identification with CsI(Tl) scintillators coupled with photodiodes

In the framework of the development of the FARCOS (Femtoscopy Array for Correlation and Spectroscopy) telescopes, we developed a CMOS frontend in C35B4C3 AMS technology for the readout of the photodiode current in CsI(Tl)-based calorimeters. The preamplifier features a continuous-reset feedback and an input PMOS transistor. The designed input dynamic range is 90 MeV Silicon equivalent. The compensation capacitor at the gain node guarantees adequate GBWPs without shape distortion and a phase margin greater than 60°. The measured integral-non-linearity over the whole dynamic range is below 0.4%. The preamplifer (intrinsic) rise-time (30%-80%) is of the order of 6-8 ns over the entire dynamic range and keeps below 12 ns when coupled with the photodiode.