Research Of Subtrigger System For The External Target Experiment In HIRFL-CSR

The heavy ion physics becomes an important field in nuclear physics. The heavy ion accelerators are the prerequisites to the heavy ion physics. The Heavy Ion Research Facility at Lanzhou Cooling Storage Ring(HIRFL-CSR) was built in our country as a large scientific facility. It has been built a large-scale scientific facility. It focused on the research of the heavy ion physics. The External target experiment is an important component on this facility. The gamma detector array of the external target experiment main purpose is to detect the γ-ray in experiments form the secondary particles when particle shooting. In order to exclude unwanted particle form the detectors and electronics as well as in the presence of noise generated during experiments, a dedicated trigger system was researched and designed for the election. his paper will discuss the research of the design of subtrigger system external target experiment.The core function of the subtrigger system is to select the events form the large particle physics experiments to ensure the identification of effective events. The detector is able to detect the effectively hit events that is interested in physics experiment, at the same time it includes both background noise and cosmic ray experiments like this invalid information. The purpose of the trigger system is to filter the large number of physics events combine with the structural and electronic characteristics of the detectors binding in a short time. It picked up the effective information in heavy ion experiment and remove invalid information. The system can save the information transfer the data to acquisition system to prepare for experimental analysis.During the research process in this paper, the number of large physics experiment facilities’ trigger system in domestic and international had been analysis and research, combined with the structural and electronic characteristics of the detectors in the external target experiment, a suitable solution has been determined for subtrigger system of gamma detector array. In this paper, the circuit hardware and trigger system core logic of the subtrigger system has been discussed. The circuit is designed base on PXI platform. The core of the trigger logic algorithm is achieved by the election on the field-programmable gate array(FPGA). Compared with traditional logic algorithms, the new logic algorithm has been optimization with the better performance to ensure system stability and flexibility. Focus on the different function modules of the subtrigger system, different test programs was application. Through specific simulation and testing tools, Functionality of the system has been verified. Test results show that the subtrigger system can meet the needs of the experiment, with the reconfigurability.Finally, this paper summarizes the logic function and circuit structure of the subtrigger system, planning for next phase of work and logic upgrade.