News from KEK
On October 26, the Belle detector at the High-Energy Accelerator Research Organization, KEK, recorded an integrated luminosity of 100 fb-1. But on October 30, a vacuum leak occurred in the beam pipe at the interaction point in the Belle. It was unrolled, and the beam pipe was taken out on November 24. It is made of beryllium and aluminum and is surrounded by silicon vertex detectors (SVD). The dose rate on the surface of the SVD due to residual radioactivity was quite low, 0.07-0.12 microSv/h. The beam pipe will be disassembled in order to investigate the cause of the vacuum leak.
The KEK-to-Kamioka (K2K) Long-baseline Neutrino Oscillation Experiment will restart on December 17.
The maximum dose was 1.6 mSv/person during the maintenance of the neutrino beam line.