Author: Takano, J.
Paper Title Page
THO1LR02
 Recent Commissioning of High-Intensity Proton Beams in J-PARC Main Ring  
 
  • Y. Sato, T. Koseki, J. Takano, S. Yamada, N. Yamamoto
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • H. Harada, M.J. Shirakata, F. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Igarashi
    KEK, Ibaraki, Japan
  
  In the J-PARC, the main ring (MR) provides high power proton beams of 240 kW (1.24·1014 protons per pulse) to the neutrino experiment. The linac energy was upgraded from 181 MeV to 400 MeV in 2013, and its current is going to be from 30 mA to 50 mA in 2014. If the beam losses are minimized and localized in the MR, the MR will have the capability to provide over 300 kW after the upstream upgrades. Based on the upgrades and improvements of the 3-50BT and the MR in 2013 and 2014, following approaches have been tested and commissioned: 2nd harmonic RFs under the faster rise-up time improvement of the injection kickers, to increase bunching factor; intra-bunch feed-back system and chromaticity patterned correction, to suppress instability; intra-bunch feed-back, tail and reflection improvement of the injection kickers, and 6D matching between the 3-50BT and the MR, to reduce injection losses; achromatic tuning at the collimator section of the 3-50BT to cut beam halo effectively; collimator upgrades, aperture enlargement at dispersion peaks, and momentum spread control, to localize beam losses in the collimator section; new operation point survey.  
slides icon Slides THO1LR02 [2.553 MB]  
 
MOPAB51 Beam Dynamics Study for J-PARC Main Ring by Using the 'Pencil' and Space-charge Dominated Beam: Measurements and Simulations 157
 
  • A.Y. Molodozhentsev, S. Igarashi, Y. Sato, J. Takano
    KEK, Ibaraki, Japan
  
  J-PARC Main Ring (MR) study has been performed during 2013-2014 to optimize the machine performance. As the result of this activity the ‘200 kW’ proton beam has been successfully extracted from MR into the ‘Neutrino’ beamline. Total particle losses, localized at the MR collimation section, have been estimated as 150 W. The 'low-losses' MR operation has been achieved after optimization the injection process, setting the MR RF system, dynamic control of the chromaticity and compensation the linear coupling resonance. In frame of this report we will discuss the obtained experimental results and compare it with simulations, performed extensively for different machine operation scenario, including the 'pencil' low intensity beam and the space-charge dominated beam. The obtained results demonstrate agreement between simulations and measurements for emittance evolution and losses for different cases. The developed MR computational model will be used to optimize the machine performance for the ‘MegaWatt’ MR operation scenario with limited losses. The modeling of the beam dynamics for these cases has been performed by using the ‘PTC-ORBIT’ combined code, installed on the KEK supercomputer.