| Paper |
Title |
Page |
| MOPCH120 |
Ground Motion Study and the Related Effects on the J-PARC
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327 |
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- S. Takeda, N. Yamamoto, M. Yoshioka
KEK, Ibaraki
- Y. Nakayama
JPOWER, Kanagawa-ken
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The power spectrum density, coherence and cross-spectrum density of the ground motion in the J-PARC site are studied to get the guideline of the beam control systems. J-PARC consists of a 600 MeV linac, a 3 GeV Rapid-cycling synchrotron (RCS) and a 50 GeV synchrotron (MR). MR provides a beam current of 15 micro-A with a period of 3 sec to either the nuclear physics experimental area or the neutrino production target. MR is a very high beam power machine, so its optimum beam loss must be kept fewer than 0.01% of an accelerated beam in order to decrease the radiation damage of accelerator components and to get easy accessibilty to them. From the point of view of beam loss, we give some detailed discussion about the relation between the MR operation and the ground motion using the observed data.
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| MOPCH121 |
Ground Motion Measurement at J-PARC
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330 |
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- Y. Nakayama, K. Tada
JPOWER, Kanagawa-ken
- S. Takeda, M. Yoshioka
KEK, Ibaraki
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In the next generation accelerator, construction of the machine on the stable ground is preferable for accelerator beam operation. We have measured ground motion at the J-PARC site under construction, where the ground is very close to the Pacific Ocean. In this paper, some of the observed results are shown, comparing the results of the previous observation at some accelerator facilities and next generation accelerator candidate sites in Japan.
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| TUPCH060 |
Beam Collimator System in the J-PARC 3-50BT Line
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1148 |
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- M.J. Shirakata, H. Oki, T. Oogoe, Y. Takeuchi, M. Yoshioka
KEK, Ibaraki
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For the J-PARC 50 GeV Main Ring Synchrotron (MR), the design beam emittance is 54 pi mm mrad. On the other hand, the 3 GeV beam from the Rapid Cycling Booster Synchrotron (RCS) may have a large halo component upto 216 pi mm mrad. In order to absorb the halo component, a beam collimator system will be installed in the beam transport line called as the 3-50BT, which connects the RCS and the MR. From the view of the hands-on maintenance, high endurance structure is adopted. The beam collimator design including the beam optics is reported in this paper.
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| TUPCH055 |
Beam Phase Measurement of Stored Bunch
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1133 |
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- T. Ohshima, A. Yamashita
JASRI/SPring-8, Hyogo-ken
- M. Yoshioka
SES, Hyogo-pref.
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We developed a system to measure synchronous phase angles for all bunches stored in the storage ring using an oscilloscope with high sampling rate. Precise phase measurement of specific bunch is required from the synchrotron radiation (SR) users, especially from the time resolved spectroscopy users. In a pump and probe experiment, the trigger timing for pumping laser should be precisely adjusted to the probe SR light. The timing of SR light is affected by the accelerating RF voltages, filling pattern, bunch currents, gap positions of insertion devices and so on. At the SPring-8, the bunch currents and the synchronous phase angles for all stored bunches can be measured within 30seconds using newly developed system. The precision of the phase angle is less than 8ps. We are now preparing to deliver the information of synchronous phase angle to SR users. The detail of the measurement system and achieved performance will be presented.
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