• M. Kago, T. Matsushita, N. Nariyama, C. Saji, R. Tanaka, A. Yamashita
  JASRI/SPring-8, Hyogo-ken
• Y. Asano, T. Fukui, T. Itoga
  RIKEN/SPring-8, Hyogo

The accelerator safety interlock system (ASIS) for the XFEL/SPring-8 protects personnel from radiation hazard. We designed the ASIS consisting of three independent systems; a central interlock system, an emergency interlock system and a beam route interlock system. The central interlock system monitors the machine tunnel security, status of beam line interlock system and radiation monitoring system. The emergency interlock system monitors status of emergency stop buttons. The beam route interlock system monitors electron beam route by inputting the current of the bending magnets at the electron-beam switching points. If any system trips, or if any system detects unsafe status, the permission signal for the accelerator operation from the system is off and the electron beam is inhibited. In addition, it is demanded that the permission signals must be transmitted within 16.6 ms. Therefore, the stability and fast response are required for the XFEL safety interlock system. We adopted programmable logic controllers (PLC) for the stability, and developed optical modules for the fast signal transmission. This paper describes system design of the ASIS.

• N. Nariyama, H. Aoyagi, M. Kago, T. Matsushita, C. Saji, R. Tanaka
  JASRI/SPring-8, Hyogo-ken
• Y. Asano, T. Itoga
  RIKEN/SPring-8, Hyogo

The accelerator safety interlock system of XFEL/SPring-8 was designed to fulfill the requirement of matching with the safety interlock system of SPring-8 because both safety systems are planning to be unified in near future to deal with the electron beam injection from XFEL to SPring-8. At XFEL, however, additional requirements for the system also existed; the designed radiation shielding requires when the electrons are not injected into the dump core properly, the beam has to be terminated within 16 msec, which corresponds to 60 Hz operation, to avoid the next bunch coming. An outline of such different design criteria is presented together with the concept of the safety interlock system. The radiation monitoring system, which was also the same as that of SPring-8, was installed by reinforcing the redundancy and response time. Gamma and neutron monitors are set at 14 positions near the assumed loss points in the accessible place of the controlled area. The dose equivalent data are sent to the radiation monitoring systems of XFEL and SPring-8, respectively, and when the measured dose exceeds the preset level, an alarm signal is sent to the safety interlock promptly.