TGLD - A 16-CHANNEL CHARGE READOUT CHIP FOR THE PHENIX PAD CHAMBER DETECTOR SUBSYSTEM AT RHIC

This paper describes TOLD, a charge readout chip for the PHENIX Pad Ch amber (PC) subsystem at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) in Upton, NY. Due to the PC's high channel d ensity, the TOLD and associated circuitry operate within the active de tector region as permanent, zero access components, with remote set-up and test during collider operation. The TGLD design accommodates vary ing pad capacitance and charge gain for three detector subassemblies t hat detect particles at three different distances from the PHENIX coll ision vertex. The design also provides adjustable discrimination thres holds from MIP/10 to 2 MIP (Minimum Ionizing Particle). Three TGLD chi ps operate with a complimentary digital memory unit (DMU) to form 48 c hannel low power, low mass, readout cards. Partitioning of readout ele ctronics and address control for robust remote operation are discussed . Component and system test results are also reported.