Maksim V. Kuzin
Present status of the SuperKEKB positron source
We report on a present status of the SuperKEKB positron source. It is composed of a tungsten target, a flux concentrator (FC) as an adiabatic matching device and large-aperture S-band accelerating structures under a static solenoidal field. Primary electron beam energy is around 3.0 GeV. In the beam commissioning during the SuperKEKB Phase-1 operation period in 2016, the operation current of the FC was limited to be below half of the design current 12 kA due to breakdowns in the FC. We replaced the FC to an improved model in April 2017, however, the breakdowns occurred also in the new FC. We are investigating the damaged FC. Results of the investigation will be shown.