We are upgrading a beamline of neutrino experimental facility at J-PARC to realize its 1.3MW operation. One of the upgrade items is to strengthen machine protection interlocks at the beamline. So far, we have developed an interlock system that monitors the output current of the power supplies for normal-conducting(NC) magnets at the primary beamline. On the other hand, we observed an event that a coil-short in one of bending magnets at a beam transport line at J-PARC (3-50BT) happened in 2019 and it caused a drift of beam orbit over the time. Our present interlock system can not detect a similar coil-short in the magnet while such change of the beam orbit may cause a serious trouble. One of possible way to detect such coil-short is to monitor a voltage of the magnet coil. Actually, a significant voltage drop between layers of the coil was observed for the 3-50BT magnet coil-short. Focusing on the fact, we are developing a system that constantly monitors the voltage value of the magnets at primary beamline and issues an interlock when there is a fluctuation exceeding a threshold value. We report the progress of development of the system.
Proceedings of the 18th International Conference on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2021, Shanghai, China