Network-Distributed Data-Acquisition System for Photoproduction Experiments With LEPS2

The LEPS2 data-acquisition (DAQ) system is built on the network-distributed DAQ-middleware framework. It consists of gatherers that collect data from detector subsystems, mergers that integrate data from gatherers, an event builder and a logger that writes data to files in the DAQ software. The 10K time projection chamber (TPC) pad signals are transmitted to 16-channel flash analog-to-digital converter (FADC) boards and transferred through the SpaceWire protocol to DAQ software components. We need to handle different subsystems with extensive variation in the number of channels. We have successfully commissioned the DAQ system of the LEPS2 detector, which includes a TPC, drift chambers (DCs), resistive plate chambers, Pb/scintillator sampling calorimeters, and neutron counters (NCs). The LEPS2 DAQ system reads approximately 10K channels from TPC and 5K channels from other detector components at a trigger rate of 100–200 Hz and an event size of 40 MB/s.