While the imaging Time Of Propagation (iTOP) subdetector of the Belle II experiment was installed in May, 2016, the commissioning and operation of this complex detector has been a challenge. This novel readout consists of 64 independent “board stacks”, each of which contains 128 channels of precision single-photon timing readout. To accomplish this sixteen 8-channel IRSX ASICs and mounted on 4 carrier cards along with a Zynq-7 FPGA. These 4 FPGAs communicate of dedicated gigabit links to a master Zynq-7 FPGA mounted on a so-called SCROD, or master control card, along with a large DDR RAM for holding calibration constants. Both the logic and processor cores are used to provide on-the-fly pedestal subtraction and precision timing feature extraction. Timing, trigger and data are provided by Belle II standard fiber optic link (Belle2link) and custom programming and trigger/timing distribution (FTSW). Performance results from final global cosmic ray running and first collision data will be presented. Particular emphasis will be placed on problems encountered and lessons learned.
|Institute||University of Hawaii at Manoa|