The RICH Chip-a CMOS integrated circuit for the PHENIX Ring Imaging Cherenkov detector

A multi-function, eight-channel integrated circuit designated as the RICH Chip has been developed for the PHENIX Ring Imaging Cherenkov detector. The chip is an element in a pipelined data acquisition system and is preceded by a photomultiplier tube and fast preamplifier and followed by an analog memory and ADC. Each channel has an energy measurement circuit consisting of an integrator and variable gain amplifier and a timing circuit consisting of a constant fraction discriminator and time-to-amplitude converter. The chip also contains two four-channel analog summing circuits and various DACs that eliminate the need for any external adjustments. Details of the design are presented.