Evaluation of a streaming-readout data acquisition system for charmed baryon spectroscopy at J-PARC

We have evaluated a trigger-less streaming-readout data acquisition (SRODAQ) system for the charmed baryon spectroscopy experiment (E50) at the J-PARC hadron experimental facility. The SRODAQ system is based on a parallel processing framework to handle data continuously sent from front-end electronics (FEE) with a time stamp. To test the SRODAQ system by integrating production-level FEE modules and actual software-implemented NestDAQ processes, a test bench equipped with detectors intended for the E50 experiment was constructed at the J-PARC K1.8BR area. A test experiment (T103) was carried out under realistic experimental conditions using an actual hadron beam with an intensity of 0.95 M/spill (spill duration 2 s). The constructed SRODAQ system handled the data during the beam extraction collected at an average rate of 260 MB/s and operated stably for 10 hours without any silent data drops. Furthermore, the scalability of the SRODAQ system was confirmed with a multiple DAQ server configuration using five DAQ server PCs, achieving a data transfer rate of 9.2 Gbps through proper load balancing in a high data transmission test. The performance of the data filtering process, called HLF (High-Level Filter), was evaluated by selecting beam particle events via time-of-flight (TOF) measurement. The HLF process correctly selected the events within the set time window, with a measured throughput of 600 MB/s for the HLF process and 1750 MB/s for the TOF calculation function. The successful integration and stable operation of the SRODAQ system in the T103 experiment provide a critical milestone toward the realization of E50.