| Paper |
Title |
Page |
| TUP011 |
Upgrade of Beam Diagnostics in LEBT and MEBT of J-PARC LINAC
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268 |
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- S. Sato, T. Tomisawa, A. Ueno
JAEA/LINAC, Ibaraki-ken
- H. Akikawa, Z. Igarashi, M. Ikegami, C. Kubota, S. Lee
KEK, Ibaraki
- Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
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After tests in Tsukuba-site, Front end part (from an ion source upto the first drift tube linac) of J-PARC LINAC was transported to Tokai-site. From the coming December, testing with H- beam is planned. After the tests in Tsukuba, a few beam current monitors are added in the low and the medium energy transport line, and those monitors are used for the machine- and the person-protection system. In this paper, design and roles of each monitor are described.
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| TUP021 |
Wire Profile Monitors in J-PARC Linac
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293 |
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- H. Akikawa, Z. Igarashi, M. Ikegami, S. Lee
KEK, Ibaraki
- Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Sato, T. Tomisawa, A. Ueno
JAEA/LINAC, Ibaraki-ken
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We plan to install wire scanners for J-PARC linac in order to measure beam profile and emittance. They have been designed to capture electrons in H-, 7um-diameter carbon wires are used in 3MeV point and 30um-diameter tungsten wires are used for 50-181MeV point. We plan to set 36 wire scanners in linac and beam dumps. In this paper, we report the result of beam test with 3MeV beam at KEK and the calculation about signal and wire temperature.
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| TUP020 |
The J-PARC L3BT Monitor System for RCS Injection
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290 |
| |
- S. Lee, Z. Igarashi, M. Ikegami, T. Toyama
KEK, Ibaraki
- H. Akikawa, T. Ohkawa
JAEA, Ibaraki-ken
- N. Hayashi, S. H. Hiroki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Sato, T. Tomisawa, A. Ueno
JAEA/LINAC, Ibaraki-ken
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The J-PARC linac-3GeV rapid cycling synchrotron (RCS) beam transport line (L3BT) monitor system will be used to tune the intensity of 5mA-50mA linac beam. The monitor system is composed of BPMs and multi wire profile scanners (MWPS) in L3BT line and RCS injection area. A non-destructive beam momentum spread monitor using a 4-stripline pickups is also developed in order to measure and control the momentum spread of linac beams. The spatial resolution of less than 0.3mm and momentum spread of less than 0.1% is required for RCS injection to avoid uncontrolled beam losses. In this paper, beam position monitor, profile monitor and momentum spread measurement for J-PARC linac is described. Preliminary results of beam size and m value measurement with quadrupole mode of the signal of 4-stripline BPMs in the KEK MEBT1 are also discussed.
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| TUP067 |
Tune-up Scenario for Debuncher System in J-PARC L3BT
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406 |
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- M. Ikegami, H. Akikawa, Z. Igarashi, S. Lee
KEK, Ibaraki
- Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- T. Morishita, S. Sato, T. Tomisawa, A. Ueno
JAEA/LINAC, Ibaraki-ken
- T. Ohkawa
JAEA, Ibaraki-ken
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We plan to start beam commissioning of J-PARC linac and the succeeding beam transport line in December 2006. The beam transport line, to which we refer as L3BT, has two key functionalities to satisfy the requirements for the succeeding ring injection. One is to reduce the momentum jitter and momentum spread, and the other is to scrape off the transverse tail. To realize the former functionality, a debuncher system is installed in L3BT which enables longitudinal gymnastics of the beam to reduce the momentum spread at the ring injection. In this presentation, the tune-up scenario for the debuncher system is presented together with simulation results on the effects of debuncher system.
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| TUP068 |
Tuning Strategy for Transverse Collimator in J-PARC L3BT
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409 |
| |
- M. Ikegami, H. Akikawa, S. Lee
KEK, Ibaraki
- H. Ao, T. Morishita, S. Sato, A. Ueno
JAEA/LINAC, Ibaraki-ken
- Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- T. Ohkawa
JAEA, Ibaraki-ken
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We plan to start beam commissioning of J-PARC linac and the succeeding beam transport line in December 2006. The beam transport line, to which we refer as L3BT, has two key functionalities to satisfy the requirements for the succeeding ring injection. One is to reduce the momentum jitter and momentum spread, and the other is to scrape off the transverse tail. To realize the latter functionality, a transverse collimator system is installed in L3BT which consists of four horizontal and four vertical collimators. In this presentation, the tuning strategy for the transverse collimator system is presented together with the main features of the collimator system.
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| THP063 |
First High-Power ACS Module for J-PARC Linac
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725 |
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- H. Ao, K. Hasegawa, K. Hirano, T. Morishita, A. Ueno
JAEA/LINAC, Ibaraki-ken
- M. Ikegami
KEK, Ibaraki
- V. V. Paramonov
RAS/INR, Moscow
- Y. Yamazaki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
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J-PARC Linac will be commissioned with energy of 181-MeV using 50-keV ion source, 3-MeV RFQ, 50-MeV DTL and 181-MeV SDTL (Separated DTL) on December 2006. It is planed to be upgraded by using 400-MeV ACS (Annular Coupled Structure), in a few years from the commissioning. The first high-power ACS module, which will be used as the first buncher between the SDTL and the ACS has been fabricated, and a few accelerating modules are also under fabrication until FY2006. Detail of cavity design and tuning procedure has been studied with RF simulation analysis and cold-model measurements. This paper describes RF measurement results, fabrication status, and related development items.
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| THP072 |
Fabrication and Low-Power Measurements of the J-PARC 50-mA RFQ Prototype
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749 |
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- Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- K. Hasegawa
JAEA, Ibaraki-ken
- A. Ueno
JAEA/LINAC, Ibaraki-ken
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In the Japan Proton Accelerator Research Complex (J-PARC) project, the beam commissioning of the H- linac will be started with a 30mA peak current. A 30mA type RFQ, which is developed for the former Japan Hadorn Facility (JHF) project, is used for the day-1 operation. However, it is required to accomplish the peak current of 50mA as soon as possible. For this purpose, we have developed an RFQ for the 50mA peak current, which is a four vane type RFQ and resonant frequency of which is 324MHz, same as the 30mA RFQ. In the R&D of this RFQ, we have adopted laser welding to join oxygen free copper blocks to be a cavity structure. The heat load of the laser welding can be more localized than that of the brazing, and the copper is not annealed, therefore, we think, it is possible to obtain more mechanical accuracy. We have developed a longitudinally 1/3 prototype cavity of the J-PARC 50mA RFQ. In this cavity, the distortion of the vane tips is measured to be less than 30 micro-meters, and the field uniformity of within 1% is obtained in a low power measurement after tuning. In this paper, we discuss about the fabrication and the low power measurement of this prototype cavity.
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