Performance of the Quench Protection Heater for the HL-LHC Beam Separation Dipole

In collaboration with CERN, High Energy Accelerator Research Organization (KEK) has designed and developed short-scale model magnets of the beam separation dipole, MBXF, which will be installed for the High Luminosity Large Hadron Collider, HL-LHC. A new quench protection heater for MBXF was designed and tested during the cold test of the short-scale models. Combining data taken since the test of the 1st model magnet, we confirmed the maximum hotspot temperatures are well below 300 K in the case of the low field (1 T) and high field (5 T) quenches, respectively. In addition, a simulation model was developed and tuned with the obtained data for the full-scale prototype magnet. The hotspot temperature after quench initiation was then computed with the new heater circuit and found to be below 300 K even for the case of failure in firing the heater.