The performance test of the Belle II Data Acquisition System

The Belle II experiment, a new generation B-factory experiment at KEK, is about to start the data taking in 2018 to search for the New Physics beyond the Standard Model with the high luminosity electron-positron collider, SuperKEKB at KEK. In order to handle with huge data size up to 30GB/sec from the detector, the Belle II data acquisition system is implemented based on a common readout scheme for detector front end electronics, an event builder with multiple PCs and network switches, and the high level trigger (HLT) PC farms with the offline reconstruction for the software trigger decision. A dedicated FPGA data processor for the pixel detector is introduced to select hits around the reconstructed tracks in the feedback from the HLT and reduce the huge data size. The DAQ is a synchronized system with a level 1 trigger, and the trigger and system clock are distributed to the readout components. Constructions of the detectors is mostly completed. Readout electronics including detector front end and back end computing system are also ready for the global system test. Performance tests of the Belle II DAQ system using the integrated modules is discussed in this document.