Speaker
Description
In early 2016, BEAST, a detector designed to monitor beam conditions for SuperKEKB, was deployed for 4 months during phase-1 of beam commissioning. The BEAST detector consisted of multiple sub-detectors including the $^3$He proportional counters. During the beam commissioning the $^3$He tubes were successful in monitoring thermal neutron backgrounds caused by collisions with beam gas and Touschek interactions. These background measurements were then compared with GEANT4 simulations. As these measurements were taken without the Belle-II detector in place, BEAST will be redeployed after the Belle-II roll-in scheduled for 2017. It is expected that electron-positron collisions will begin by early 2018 for phase-2 beam commissioning.
During the second phase of BEAST the $^3$He tubes will continue to monitor thermal neutron rates. During phase-2 commissioning positron-electron collisions will begin which produces a large number of high energy by-products. These by-products could be damaging to sensitive components of the Belle-II detector, so the $^3$He detectors will measure the thermal neutron rate and the rates will be extrapolated to higher collision rates and beam currents.
Installation of the majority of BEAST, including the $^3$He tubes, is expected to occur in September 2017. Before the $^3$He tubes are reinstalled they will be recalibrated at the University of Victoria, and the data acquisition system will be upgraded. In particular, the cabling will be replaced with zero-halogen components to meet requirements for high radiation environments. When phase-2 begins $^3$He will be ready to provide useful insights into the SuperKEKB beam and the operating environment of Belle-II.
