A monolithic charge-to-amplitude converter (QAC) chip for fast readout of photomultiplier

A fast charge-to-amplitude converter (QAC) chip has been developed for the readout electronics of the electromagnetic calorimeter (ECAL) of the COMPAS S experiment at CERN SPS. It is fabricated using a new advanced complementa ry bipolar process from Harris Semiconductor with intrinsic radiation hardn ess. The new QAC chip performs the conversion of fast current pulses genera ted by a photomultiplier tube (PMT) into voltage signals. The output voltag e of the QAC is directly proportional to the input current signal. The circ uit block diagram, main features and characteristics of the chip are descri bed. Simulation curves as well as test results of QAC prototypes are presen ted. They show excellent performances for the COMPASS experiment as well as for uses in high energy and nuclear physics experiments to manage fast cur rent signals. (C) 2000 Elsevier Science B.V. All rights reserved.