Construction and Commissioning of a New Direct Beam Transport Line of PF-AR

Abstract

PF-AR is a synchrotron light source located in High Energy Accelerator Research Organization (KEK) and supplies hard X-ray with single bunch operation. The injector “LINAC” of PF-AR is shared with other three rings: High Energy Ring (HER) and Low Energy Ring (LER) of SuperKEKB and PF. In KEKB era, the beam transport line (BT) of PF-AR and HER was shared, and the injection had to be interrupted for ten minutes at least for the standardization of the magnets when changing the objective ring for the injection. In the winter of FY2017, phase 2 operation of SuperKEKB will begin, and its Touschek lifetime is calculated as about ten minutes. This is shorter than in KEKB era, and the sharing of the BT cannot be adopted anymore for the simultaneous operation of both PF-AR and SuperKEKB. In order to realize this, we have constructed a new BT dedicated to PF-AR. The excavation of the new tunnel started in 2013, and the infrastructure construction was completed in 2014. The commissioning with the new direct BT started on 13 February, and the user-run was resumed in April 2017. The machine study for the top-up operation of PF-AR and the simultaneous top-up operation of all 4 rings are planed in autumn 2017 and in autumn 2018 respectively.