• P.K. Saha, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• Y. Irie
  KEK, Ibaraki
• T. Toyama
  J-PARC, KEK & JAEA, Ibaraki-ken

The beam loss issues connected to the nuclear scattering together with the multiple Coulomb scattering at the charge-exchange foil during the multi-turn injection has been studied in detail for the RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex). Recently, during the beam commissioning of RCS, some experimental data related to such issue has been taken and thus a comparison of the measured beam loss to the estimated one is reported in this paper. When the beam loss from such a source is unavoidable, a realistic estimation is quite important for a fair design of the injection system and the vicinity in order to reduce especially, the uncontrolled beam loss.

• H. Hotchi, N. Hayashi, Y. Hikichi, S. Hiroki, J. Kamiya, K. Kanazawa, M. Kawase, M. Kinsho, M. Nomura, N. Ogiwara, R. Saeki, P.K. Saha, A. Schnase, T. Shimada, Y. Shobuda, K. Suganuma, H. Suzuki, H. Takahashi, T. Takayanagi, O. Takeda, F. Tamura, N. Tani, T. Togashi, T. Ueno, M. Watanabe, Y. Watanabe, K. Yamamoto, M. Yamamoto, Y. Yamazaki, H. Yoshikawa, M. Yoshimoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• A. Ando
  LASTI, Hyogo
• H. Harada
  Hiroshima University, Graduate School of Science, Higashi-Hiroshima
• K. Hasegawa, Y. Irie, C. Ohmori, M. Yoshii
  KEK, Ibaraki
• K. Satou, Y. Yamazaki
  J-PARC, KEK & JAEA, Ibaraki-ken

The beam commissioning of the J-PARC 3-GeV RCS started in October 2007. The initial machine parameter tuning and underlying beam studies were completed in February 2008 through various beam dynamics measurements, such as optical functions, turn-by-turn beam positions, and transverse and logitudinal beam profiles. Now the RCS is in transition from the first commissioning phase to the next challenging stage and our efforts hereafter will be focused on higher beam power operations. In this paper, we describe experimental results obtained in the high intensity demonstrations in October 2008, together with the corresponding simulation results.

• T. Toyama, D.A. Arakawa, A. Arinaga, Y. Hashimoto, S. Hiramatsu, S. Igarashi, S. Lee, H. Matsumoto, J.-I. Odagiri, M. Tejima, M. Tobiyama, N. Yamamoto
  KEK, Ibaraki
• K. Hanamura, S. Hatakeyama
  MELCO SC, Tsukuba
• H. Harada
  JAEA, Ibaraki-ken
• N. Hayashi, K. Yamamoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• K. Satou
  J-PARC, KEK & JAEA, Ibaraki-ken

Beam commissioning of the J-PARC MR has been going on from May 2008. The beam was one bunch of 4·10¹¹ protons, nearly one hundredth of the design value. Here describe performances of the beam diagnostic devices: DCCT's, BPM's, BLM's, profile monitors and tune meters. Diagnostic design for the design intensity will be also included.

Slides

• M. Yoshimoto, N. Hayashi, M. Kawase, F. Tamura, M. Yamamoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• M. Yoshii
  KEK/JAEA, Ibaraki-Ken

In order to observe two-dimensional beam profiles in the longitudinal phase space, the reconstruction techniques with the computer tomography algorithms can be adopted at the J-PARC RCS. On the assumption that the longitudinal profiles should not be disturbed for one period of the synchrotron oscillation, such two-dimensional profiles can be reconstructed easily from one-dimensional bunch beam profiles, which are measured for every turn by the wall current monitor. In this presentation, we introduce the experimental results and the comparison to the longitudinal beam tracking simulation, and we discuss the technical issues and applicability of this longitudinal tomography techniques.