Design of control system of neutron beam shutters for 1MW spallation neutron source at Japan Proton Accelerator Research Complex (J-PARC)

Takada, Hiroshi   ; Kai, Tetsuya   ; Oikawa, Kenichi   ; Sakai, Kenji 

We have designed the control systems of neutron beam shutters of the 1-MW spallation neutron source under the Japan Proton Accelerator Research Complex (J-PARC) project. The control system was designed that users were able to open and/or close shutters at experimental halles during a beam-time and facility's personnel could move shutters near the shutter drive mechanism room at the maintenance period. Moreover, it was designed to keep the primary condition that personnels were allowed to enter the instrument room when the shutter is closed. This condition was integrated to the Personnel Protection System (PPS) to ensure the safety of the personnel. Components were also designed to enhance the reliability of the control system as follows: shutter close position is detected independently by two kinds of devices of a mechanical limit switch and a rotary encorder, and the power supply for the shutter system was connected with an UPS to prevent loss of signals in case of a power failure.