Abstract:
Nuclear astrophysics is an interdisciplinary research field that integrates nuclear physics and astrophysics. The ultimate goal of nuclear astrophysics is to understand how nuclear processes generate the energy of stars over their lifetimes and, in doing so, synthesize heavier elements from the primordial hydrogen and helium in the big bang which lead to the expanding universe. It mainly aims at study of the origin of elements and how nuclear processes affect the evolution and fate of stars in the universe. In order to meet the need of the nuclear astrophysics experiment, a low energy, high stability, high-current and high-voltage accelerator was required to carry out the related nuclear astrophysics experiments by direct measurement method under the ultra-low background environments. A high-current and high-voltage accelerator was developed by China Institute of Atomic Energy and Institute of Modern Physics for the underground laboratory of Jinping Mountain. The hardware structure of the accelerator control system adopted the distributed control system based on PLC. The PROFIBUS field bus was used to realize data exchange between the main frame and extended frame in PLC control system. Industrial ethernet was used for data communication between the field control layer and the operation layer. The control system software adopted the distributed control framework based on EPICS clients/server mode, which is composed of interface module OPI for clients, input/output control module IOC for server and channel access module CA. The operation monitoring software with the interactive control interface was developed with EPICS configuration software. There are main control window, vaccum system window, safety interlock setting window, and ion source windows. The parameters of accelerator can be set and displayed easily. The combination of hardware and software protection was adopted to ensure the accelerator’s reliability. A complete safety interlock system was installed to ensure the safety of equipment and personnel. The problem of strong interference caused by high-voltage sparks is taking a series of measures, for example reasonable grounding mode, adding high performance filters and protective device for the power supply system of control system and equipment, writing fault treatment program and so on. At present, the accelerator has run for over 3 500 h and some important nuclear astrophysical experiments have been carried out successfully.