A monolithic charge-to-amplitude converter (QAC) chip for fast readout of photomultiplier
11 March 2000
A fast charge-to-amplitude converter (QAC) chip has been developed for the readout electronics of the electromagnetic calorimeter (ECAL) of the COMPASS experiment at CERN SPS. It is fabricated using a new advanced complementary bipolar process from Harris Semiconductor with intrinsic radiation hardness. The new QAC chip performs the conversion of fast current pulses generated by a photomultiplier tube (PMT) into voltage signals. The output voltage of the QAC is directly proportional to the input current signal. The circuit block diagram, main features and characteristics of the chip are described. Simulation curves as well as test results of QAC prototypes are presented. They show excellent performances for the COMPASS experiment as well as for uses in high energy and nuclear physics experiments to manage fast current signals. (C) 2000 Elsevier Science B.V. All rights reserved.