KEK electron/positron injector LINAC safety system

At the KEK electron/positron injector LINAC, simultaneous top-up injection into four independent storage rings and a positron damping ring has been successfully performed since May 2019. To maintain long-term stable beam operation under such a complex operational scheme, high availability of the control system is essential. A reliable safety system is also critical for preventing radiation-related incidents involving personnel and for protecting machine components. The control system at the KEK LINAC has been developed using the EPICS framework, which is widely adopted at particle accelerator facilities. In contrast, the safety system was initially developed independently of the EPICS framework. To ensure seamless integration between the control and safety systems, an EPICS IOC for the safety system was implemented using the netDev device support. Moreover, a newly developed beam operation logic status GUI enables quick identification of the causes of abnormal LINAC operating conditions. This paper presents a detailed overview of recent improvements to the KEK LINAC safety system.