| Paper | Title | Page |
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| MOPEC068 | High Intensity Beam Operations in the J-PARC 3-GeV RCS | 624 |
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We have recently demonstrated 300-kW output in the J-PARC 3-GeV RCS. In this paper we will discuss beam dynamics issues in such a high intensity beam operation together with the corresponding beam simulation results. |
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| MOPE020 | Beam Based Alignment of the Beam Position Monitor at J-PARC RCS | 1005 |
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The J-PARC RCS is an M-Watt class rapid cycling synchrotron and it has delivered an intensive beam to the neutron target and the MR. In order to overcome large space charge effect, its physical aperture is designed to be more than 250mm in diameter. Even though its chamber size is very large, the BPM system gives precise data to determine beam optics parameters of the ring. For this purpose, only relative positions and resolutions are important. However, for much higher intensity, the absolute beam position and accurate COD correction are indispensable. We have carefully installed the BPM and measured the position with respect to the quadrupole magnet (QM) nearby. But it is also necessary to estimate its absolute position by using beam. If each QM could be controlled independently, the simple beam based alignment technique can be utilized, but it is not the case for RCS. There are seven families of QM, and only each family can be controlled at one time. We developed a new technique by expanding the simple method for the case of multiple QM focusing changed simultaneously, and applied to the J-PARC RCS. The paper describes this method and discussed about experimental results. |
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| WEPEB065 | Beam Loss of J-PARC Rapid Cycling Synchrotron at Several Hundred kW Operation | 2842 |
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A 3GeV Rapid-Cycling Synchrotron (RCS) in Japan Proton Accelerator Research Complex (J-PARC) has continuously provided more than 100kW proton beam to the Neutron target since October 2009. And we also successfully accelerated 300kW beam for one hour on December 10th by way of trial. We found some problems through these experiences. We report those problems and the residual dose in such high intensity operation. |
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| THPEB018 | Systematic Beam Loss Study due to the Foil Scattering at the 3-GeV RCS of J-PARC | 3921 |
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The beam loss caused by the nuclear scattering together with the multiple Coulomb scattering at the stripping foil is one of the key issue in RCS (Rapid Cycling Synchrotron) of the J-PARC (Japan Proton Accelerator Research Accelerator). In order to have a very realistic understanding, a systematic study with both experiment and simulation has been carried out recently. A total of seven targets with different thickness were used and the measured beam losses were found to be good in agreement with that in the simulation. A detail and realistic understanding from such a study will be very useful not only to optimize the foil system including the thickness and size at present with the injection beam energy of 181 MeV but also for the near future upgrade with 400 MeV and in addition can be a good example for similar existing and proposing projects. |
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| THPEB020 | Beam Study Results with HBC Stripping Foils at the 3-GeV RCS in J-PARC | 3927 |
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The hybrid type thick boron-doped carbon (HBC) stripping foils are installed and used for the beam injection at the 3GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex). The HBC foils are developed by Sugai group in KEK, which improved the lifetime drastically. Up to now, the performance deterioration of the stripping foils can not be seen after the long beam irradiation for the 120kW user operation and 300kW high power beam demonstration at the RCS. In order to examine the characteristic of the HBC foils, various beam studies were carried out. The beam-irradiated spot at the foil was measured by scanning the foil setting position, the charge exchange efficiency was evaluated with various thickness foils, and the effect of the SiC fibers supporting the foil mounting was checked with different mounting foils. Beam study results obtained with using the HBC foils will be presented. In addition, the trends of outgas from the stripping foils and the deformations of the foils during the beam irradiation will be reported. |
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| THPE069 | Simulation of Space Charge Effects in JPARC | 4677 |
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Nonlinear space charge interaction in high intensity proton rings causes beam loss, which limits the performance. Simulations based on particle in cell method has been performed for JPARC-Rapid Cycle Synchrotron and Main Ring. Beam loss estimation during acceleration and resonances analysis are discussed with various simulations using dynamic and frozen models. |