Studies of the LBL CMOS integrated amplifier/discriminator for randomly timed inputs from fixed target experiments

A group at Lawrence Berkeley Laboratory (LBL) has reported an elegant CMOS VLSI circuit for amplifying, discriminating, and encoding the signals from highly segmented charge-output devices, e.g. silicon strip detectors or pad readout structures in gaseous detectors. The design exploits switched-capacitor circuits and the well-known time structure of data acquisition in colliding-beam accelerators to cancel leakage effects and switching noise. For random inputs, these methods are not directly applicable. However, the high speed of the reset switches makes possible a mode of operation for fixed target experiments that uses fast resets to erase unwanted data from random triggers. Data acquisition in this mode has been performed. Details of operation and measurements of noise and rate capability are presented