Speaker
Description
The SuperKEKB accelerator is an asymmetric-energy collider using 7 GeV electrons and 4 GeV positrons. The two rings, each with a circumference of approximately 3 km, are installed in a tunnel buried 11 m underground. The beam is maintained by more than 2,600 magnets, and the final optical system uses superconducting magnets; the interactions are recorded by the Belle II detector. Most of the magnets are huge, weighing several metric tons, and employ a water-cooling system using hollow conductors. The accelerator tunnel and the cooling water systems for half of the magnets were carried over from the TRISTAN accelerator and have been in operation for over 40 years. Furthermore, the remaining half of the cooling systems have also been in operation for 10 years since construction. Currently, SuperKEKB operates on its standard several-month schedule—from fall through spring—with maintenance conducted on only one day each month. This approach is made possible by the insights we have gained from the lessons learned over the past 40 years. The most recent operation concluded without any major issues regarding the magnet cooling water. To ensure stable operation, we have established numerous tasks to be addressed through daily maintenance during operation and during the extended summer shutdown period.
In this presentation, we will explain the current status of the cooling water and maintenance procedures, also report on past failures and new challenges we are currently facing.