• M. Ikegami
  KEK, Ibaraki
• A. Miura, G.H. Wei
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• H. Sako
  JAEA, Ibaraki-ken

The user operation of J-PARC linac was started in December 2008, and it has been operated with the limited beam power of less than 1.2 kW making efforts at improving hardware availability. Since November 2007, the beam power from the linac has been increased to 7.2 kW that corresponds to 120 kW from the downstream 3-GeV synchrotron. We also performed a high-power demonstration run with 18 kW (or 300 kW from the synchrotron) that corresponds to the design beam power for the present configuration. In the course of the beam power ramp-up, we have suffered from significant beam losses in the beam transport line after the linac. Accordingly, the emphasis of the beam tuning has been shifted to the mitigation of the uncontrolled beam losses. Some of the loss mechanisms are identified in the beam studies, and we have succeeded in mitigating them. In this paper, we present recent progress in the beam commissioning of J-PARC linac with emphasis on the effort to mitigate the beam losses.

• A. Miura
  JAEA/J-PARC, Tokai-mura
• H. Akikawa, M. Ikegami
  KEK, Ibaraki
• H. Sako
  JAEA, Ibaraki-ken

A wire scanner monitor (WSM) is one of essential measurement devices for beam commissioning of current accelerators. J-PARC Linac also employs a number of WSMs for transverse beam profile. The transverse matching is performed based on the measured beam width. In addition, we have tried to measure halo component with the BSMs. In this paper, we present the experimental results obtained in a beam study to characterize the operational performance of the WSM.