| Paper | Title | Page |
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| TUPAL017 | Performance and Status of the J-PARC Accelerators | 1038 |
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| The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a 30 GeV Main Ring Synchrotron (MR). Regarding 3 GeV beam from the RCS, we delivered it at 150 kW to the materials and life science experimental facility (MLF), for the neutron and muon users. The beam powers for the neutrino experiment at 30 GeV was 420 kW in May 2016, but increased to 470 kW in February 2017 thanks to the change and optimization of operation parameters. For the hadron experimental facility which uses a slow beam extraction mode at 30 GeV, we delivered beam at a power of 37 kW, after the recovery from a trouble at an electro static septum. We have experienced many failures and troubles to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL017 | |
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| TUPAL021 | Evaluation of Activated Nuclides Due to Secondary Particles Produced in Stripper Foil in J-PARC RCS | 1048 |
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| Multi-turn charge-exchange beam injection is key technique to achieve the high intensity proton beam accelerators. In the J-PARC RCS, 400MeV H− beams from the LINAC are converted to H+ beam with the stripper foils, and then injected into the ring. The stripper foil is irradiated by not only the injecting H− beams but also the circulating H+ beams. The high energy and high power beam irradiation into the foil induces the nuclear reactions, and generated secondary neutrons and protons. These secondary particles causes high residual does around the stripper foil. Now, to identify species of secondary particles and to identify energies and emission angles, activation analysis method using the sample pieces is considered. In this presentation, we report the result of the evaluation of this activation analysis with PHITS codes. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL021 | |
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| WEPAL014 | Non-Distructive 2-D Beam Profile Monitor Using Gas Sheet in J-PARC LINAC | 2177 |
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We have been developed a beam profile monitor using interaction between the beam and the gas molecules distributed in sheet shape*. Generated luminescence or ions by passing the beam through the gas sheet has the information of cross-section shape of the beam. The gas sheet beam monitor will become a useful tool to measure the profile of high power beams because it has no breakable element such as wires and a 2-D beam profile at a certain position of beam line can be immediately obtained by just injecting the gas. Previously, the development of the gas sheet generator and successful demonstration of the beam profile measurement were reported. This time, we applied a gas sheet monitor to J-PARC LINAC, where the negative hydrogen atoms (H−) are accelerated to the energy of 400 MeV in the normal operation. Most challenging factor was the development of the gas sheet monitor system, which generates the enough dense gas sheet to detect the clear image of the beam profile without harmful effect on the ultra-high vacuum in the beam line. We will report the gas sheet beam monitor system for J-PARC LINAC and the results of the first measurement of the beam profile.
* N. Ogiwara, et al., Proceedings of IPAC2016, p.2102. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL014 | |
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| WEPAL018 | A Non-destructive 2D Profile Monitor Using a Gas Sheet | 2190 |
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| We are developing a non-destructive and fast-response beam profile monitor using a dense gas sheet target. To make a gas sheet, we use the beaming effect, which is well known in vacuum science and technology. The emitted molecules through a long rectangular channel, which has a very small ratio of the gap to the width, are forced to concentrate on a plane. The gas sheet with a thickness of 1.5 mm and the density of 2×10-4 Pa was easily generated by the combination of the deep slit and the thin slit. Here, the gas sheet was produced by the deep slit, and the shape of the sheet was improved by the thin slit. The usefulness of this monitor was shown by the following experiments: 1) For the electron beam of 30 keV with a diameter greater than 0.35 mm, the position and the two-dimensional profiles were well measured using the gas sheet. 2) Then the profiles of the 10 and 400 MeV proton beam with a current of several microamperes were well measured, too. 3) Recently, the profiles of the 400 MeV H− ion beams in J-PARC linac were measured. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL018 | |
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| WEPAL022 | Operating Experience of Water Cooling System in the J-PARC LINAC and RCS | 2203 |
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| The cooling system for the J-PARC LINAC and RCS uses a total of 25 circulation pumps to cool the accelerator devices. In February 2017, we experienced damage of circulation pumps due to low flow rate, and started the development of an abnormality detection system concentrating on the vibration measurements of the circulation pumps. In this report, the vibration measurement results of the coolant circulation pumps and the development status of abnormality detection through multivariate analysis using vibration values are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL022 | |
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