Interlock of Beam Loss at Low Energy Part of J-PARC Linac

J-Parc linac has developed the output beam power by increasing of acceleration energy and the peak beam current. The beam loss is getting serious along with increasing the output beam power, however, the beam loss caused at the low energy part is difficult to detect due to the low energy radioactive emission. An interlock system has been developed to prevent from the sufficient material activation using the beam current monitors. In the system, an electrical circuit to take the beam transmission between two beam current monitors is newly designed and fabricated. This paper describes the performance of the electrical circuit and the system configuration will be introduced.