P o S(TIPP2014)171 128 channel waveform sampling digitizer/readout in the TOP counter for the Belle II upgrade

E-mail: mza.AT.phys.hawaii.edu Extremely fast Micro-Channel Plate PhotoMultiplier Tubes (MCP-PMTs) and multi-gigasample per second (GSa/s) waveform sampling ASICs will allow precision timing to play a pivotal role in the next-generation of Ring Imaging Cherenkov (RICH) detectors. We have developed a second prototype of the electronics to instrument the Time of Propagation (TOP) counter for the Belle II detector at KEK in Tsukuba, Japan. The front-end electronics modules consist of an array of waveform sampling / digitizing ASICs controlled by FPGAs with embedded microprocessor cores. The ASICs digitize amplified signals from an array of multi-anode MCP-PMTs coupled to a quartz radiator bar. Online feature-extraction is performed directly on the front-end via digital signal processing. Readout and control are done via multi-gigabit per second fiber optic links to a custom back-end. A previous generation of these modules has been running in a prototype Focusing Detection of Internally Reflected Cherenkov (FDIRC) counter mounted in a Cosmic-Ray Stand (CRT) at SLAC continuously for over 12 months. The most recent version was taken to a beam test at the LEPS experiment at the Japanese SPring-8 facility in mid-2013. These experiences have influenced the design of the next set of ASICs and PCBs for the front-end