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Title |
Other Keywords |
Page |
| MOP19 |
Particle Distributions at the Exit of the J-PARC RFQ
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simulation, rfq, linac, injection |
78 |
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- Y. Kondo, A. Ueno
JAERI, Ibaraki-ken
- K. Ikegami, M. Ikegami
KEK, Ibaraki
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A 324 MHz, 3 MeV RFQ (Radio-Frequency Quadrupole) linac with 3.115 m vane length is used as the first RF linac of the J-PARC linac. The results of the J-PARC linac end-to-end (from the RFQ entrance to the injection point of the RCS) simulations significantly depend on the initial particle distributions. In the transverse phase spaces, Gaussian particle distributions, whose parameters were decided to reproduce the emittance measured in the LEBT (Low Energy Beam Transport), was used at the entrance of the RFQ. Two simulation codes, PARMTEQM and TOUTATIS, were used to produce the particle distributions at the exit of the RFQ. Since the simulated emittances showed good agreements with the emittances measured at downstream of the RFQ, they were confirmed to have the validity to be used as the initial distribution of the end-to-end simulation.
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| TUP21 |
Beam Dynamics Design of J-PARC Linac High Energy Section
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linac, injection, simulation, rfq |
339 |
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- M. Ikegami, T. Kato, S. Noguchi
KEK, Ibaraki
- H. Ao, Y. Yamazaki
JAERI/LINAC, Ibaraki-ken
- K. Hasegawa, T. Ohkawa, A. Ueno
JAERI, Ibaraki-ken
- N. Hayashizaki
TIT, Tokyo
- V.V. Paramonov
RAS/INR, Moscow
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J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac. Recently, the beam dynamics design of the ACS part has been slightly modified to reduce construction cost. Namely, the number of klystron modules are reduced from 23 to 21, and the number of accelerating cells in one klystron module is increased from 30 to 34 to maintain the total energy gain. This design change curtails the margin for RF power by around 5 %, and the total length of the ACS section is nearly unchanged. The beam matching section between SDTL and ACS is also revised correspondingly. These modifications of the design are described in this paper together with 3D particle simulation results for the new design.
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| TUP85 |
J-PARC Linac Alignment
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alignment, linac, quadrupole, monitoring |
474 |
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- M. Ikegami, C. Kubota, F. Naito, E. Takasaki, H. Tanaka, K. Yoshino
KEK, Ibaraki
- H. Ao, T. Itou
JAERI/LINAC, Ibaraki-ken
- K. Hasegawa, T. Morishita, N. Nakamura, A. Ueno
JAERI, Ibaraki-ken
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J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac, and its total length is more than 400 m including the beam transport line to the succeeding RCS (Rapid Cycling Synchrotron). In high-current proton accelerators, precise alignment of accelerator components is indispensable to reduce uncontrolled beam loss and beam quality deterioration. In this paper, planned schemes for the linac alignment is presented together with instrumentation for the long-term ground-motion watching.
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| THP88 |
Longitudinal Bunch Shape Monitor Using the Beam Chopper of the J-PARC
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linac, rfq, emittance, proton |
806 |
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- F. Naito
KEK, Ibaraki
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We propose the longitudinal bunch shape monitor for the low energy part of the linac of the J-PARC. The monitor uses the beam chopper cavity installled in the MEBT line between thr RFQ and the DTL of the J-PARC as a kind of the bunch rotator. Consequentry the longitudinal bunch shape is measured along the horizontal direction. If we can measure the energy distribution of the bunch also, the longitudinal emittance of the beam is derived. In the paper, the basic idea of the monitor is discussed in detail.
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