Design of the Data Acquisition System for the HERD Transition Radiation Detector Prototype

The transition radiation detector (TRD) of the high-energy cosmic radiation detection (HERD) facility uses the relationship between high-energy charged particle transition radiation (TR) and the Lorentz factor to calibrate the energy of TeV-band protons in HERD calorimeters. It can also independently conduct X-ray observation and monitor gamma-ray bursts (GRBs). The TRD consists of detector units, front-end electronics (FEE), and a data acquisition (DAQ) system. The DAQ system is responsible for the overall power management of the TRD, communication, and triggering between the TRD and HERD, data processing of the detector units, control of multiple modules within the TRD, and in-orbit operation of the whole TRD. Here, we report a DAQ system of the TRD prototype, which connects six front-end circuit boards, six high-voltage (HV) circuit boards, a turntable device, an HERD trigger system, and HERD electronics. It adopts a structure with separate data and electrical components. The power sections of the FEE, HV, turntable device, and DAQ system are designed as a power circuit board, while the FEE data transmission and telemetry, triggering, main controller, storage, and communication are designed as a data circuit board. We tested the DAQ system at the European Organization for Nuclear Research (CERN), and the results show that the system can meet the requirements of the TRD prototype in terms of power, communication, data processing, and overall control. In addition, we demonstrate that the DAQ system has been redundantly designed to enhance adaptability.