Design of machine protection system for CAFe facility

Abstract

In an accelerator-driven sub-critical system (ADS), a strong proton beam from a high-power proton accelerator irradiates a spallation target to produce very intense neutrons for driving a reactor. Currently, the China ADS front-end demo linac (CAFe) facility is being built to provide strong beam with the beam intensity of several mAs. This paper reports the machine protection system (MPS) of the CAFe facility, which prevents or minimizes the beam-induced damages or the damages from other sources to the machines in the accelerator. The MPS of CAFe facility works under the framework of experimental physics and industrial control system (EPICS). The developed machine protection system includes fast protection function and slow interlock function, where the fast function is performed by FPGA controller and the slow function is performed by PLC controller. Based on the reports on the status of all relevant subsystems, MPS will either perform an emergency shutdown of the beam or machine or will permit normal operation. When an emergency shutdown of the beam is needed, MPS switches off the ion source or switches on the chopper. In addition to its protective role, MPS will also trace the origin of an emergency shutdown. The developed MPS has played an important role during the commissioning and successful operation of the CAFe facility at the end of 2019.