• M. Ikegami
  KEK, Ibaraki
• Y. Kondo, T. Morishita, H. Sako
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

The beam commissioning of J-PARC linac has been started since November 2006. Numerical studies have been conducted since then to analyze the experimental results obtained in the beam commissioning and deepen our understanding on the underlying physics. Particular efforts are exerted on the analyses of the transverse emittance measurement at MEBT, the phase scan measurement for DTL, and the rms width response to a quadrupole magnet variation. All the measurements are essential to realize a fine tuning of the linac, and it is of practical importance to have a physical insight into the obtained results. In these studies, various simulation tools are employed in accordance with the required capacity. In this paper, the on-going numerical studies for J-PARC linac are reviewed, and we discuss on the directions in which we should pay further efforts.

• M. Ikegami
  KEK, Ibaraki

The beam commissioning of J-PARC linac has been started since November 2006, and the initial commissioning has been completed in September 2007. Since then, the linac beam has been supplied to the succeeding RCS (Rapid Cycling Synchrotron) for its commissioning. The emphasis of the linac tuning has been shifted to the stabilization of the beam parameters, and better beam availability has gradually been required for the linac operation. On the other hand, the average beam power is rather limited because we are still in the initial commissioning stage for RCS and MR (Main Ring). The hourly average of the beam power from RCS is limited to 4 kW due to the available beam dump capacity. Accordingly, we still have little experience on the machine activation with a high-power and stable beam operation. In this regard, we are in a transitional stage for our linac from commissioning to operation. In this paper, we present the current linac performance and operational experiences obtained so far after briefly reviewing the commissioning history. Particular emphasis is put on the technical challenges we faced up to the present. Future plans to increase the beam power are also discussed.