IPAC2017 - List of Authors (Miura, A.)

Paper	Title	Page
MOPAB068	Bunch Shape Monitor Development in J-PARC Linac	271
	A. Miura, J. Tamura JAEA/J-PARC, Tokai-mura, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Miyao KEK, Ibaraki, Japan
	At Japan accelerator reserch complex (J-PARC), the linac, which serves as the injector for the downstream 3-GeV synchrotron, accelerates a negative-hydrogen-ion beam (H⁻) to obtain a 400-MeV beam energy. We use an accelerating frequency of 324 MHz for the accelerator cavities and of 972 MHz. Both the centroid-phase set point at the frequency jump from 324 MHz to 972 MHz and the phase-width control are key issues for suppressing the excess beam loss. In order to optimize a set point of the tuning cavities, we developed a bunch-shape monitor (BSM) to measure the phase width as well as a tuning strategy to minimize the beam loss. In the development of the BSM, the design developed in the INR, Russia. Because the BSM had first experienced to be used between accelearation cavities, we need to protect the leak-magnetic field from quadrupole magnets and outgas impacts to cavities. We installed a BSM again in the beamline, BSM started to measure the phase width and evaluated its performances with a peak-beam-current dependence. We proposed new strategy to use BSM-measurment data for the tuning cavity. This paper describes the BSM development, its modification, and new strategy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB068
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MOPAB070	Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS	277
	N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB070
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MOPAB071	A Beam Position Monitor for the Diagnostic Line in MEBT2 of J-PARC Linac	281
	A. Miura, Y. Kawane, J. Tamura JAEA/J-PARC, Tokai-mura, Japan T. Miyao KEK, Ibaraki, Japan
	In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H⁰) generation from the negative hydrogen ion (H⁻) beam is one of key issues to mitigate the beam loss. In order to diagnose the H⁰ particles, we installed the bump magnets to make a chicane orbit of the H⁻ beam. To evaluate the horizontal shifts of the beam orbit, a beam position monitor (BPM) is fabricated. The BPM measures the shift-positions with various driving currents of the bump magnets. We employed the WSM to measure the H⁻ beam profile. It also help us to compare the shift-positions measured by BPM. In this paper, the design and the performance of the BPM is described. In addition, we describe how to compare the shift position.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB071
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TUPVA096	Detection of H⁰ Particles in MEBT2 Chicane of J-PARC Linac	2308
	J. Tamura, H. Ao, T. Maruta, A. Miura, T. Morishita, K. Okabe, M. Yoshimoto JAEA/J-PARC, Tokai-mura, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	In the Japan Proton Accelerator Research Complex (J-PARC), H⁰ particles generated by collisions of accelerated H⁻ beams with residual gases are considered as one of the key factors of the residual radiation in the high energy accelerating section of the linac. To diagnose the H⁰ particles, the new beam line for analyzing H⁰ and H⁻ particles was installed in the second medium energy beam transport (MEBT2), which is the matching section from the separated-type drift tube linac (SDTL) to the annular-ring coupled structure linac (ACS). The analysis line consists of four dipole magnets for giving the H⁻ beam chicane orbit, and a wire scanner monitor (WSM) for measuring the horizontal shift of the H⁻ beam. To detect the H⁰ particles, a carbon plate is installed to the WSM. In the beam commissioning, we detected the signals of H⁰ particles penetrating the plate and observed the transition of the signal with various vacuum condition in the SDTL section.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA096
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Paper

Title

Page

Bunch Shape Monitor Development in J-PARC Linac

271

A. Miura, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
T. Miyao
KEK, Ibaraki, Japan

At Japan accelerator reserch complex (J-PARC), the linac, which serves as the injector for the downstream 3-GeV synchrotron, accelerates a negative-hydrogen-ion beam (H⁻) to obtain a 400-MeV beam energy. We use an accelerating frequency of 324 MHz for the accelerator cavities and of 972 MHz. Both the centroid-phase set point at the frequency jump from 324 MHz to 972 MHz and the phase-width control are key issues for suppressing the excess beam loss. In order to optimize a set point of the tuning cavities, we developed a bunch-shape monitor (BSM) to measure the phase width as well as a tuning strategy to minimize the beam loss. In the development of the BSM, the design developed in the INR, Russia. Because the BSM had first experienced to be used between accelearation cavities, we need to protect the leak-magnetic field from quadrupole magnets and outgas impacts to cavities. We installed a BSM again in the beamline, BSM started to measure the phase width and evaluated its performances with a peak-beam-current dependence. We proposed new strategy to use BSM-measurment data for the tuning cavity. This paper describes the BSM development, its modification, and new strategy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB068

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB070

Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS

277

N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB070

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB071

A Beam Position Monitor for the Diagnostic Line in MEBT2 of J-PARC Linac

281

A. Miura, Y. Kawane, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
T. Miyao
KEK, Ibaraki, Japan

In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H⁰) generation from the negative hydrogen ion (H⁻) beam is one of key issues to mitigate the beam loss. In order to diagnose the H⁰ particles, we installed the bump magnets to make a chicane orbit of the H⁻ beam. To evaluate the horizontal shifts of the beam orbit, a beam position monitor (BPM) is fabricated. The BPM measures the shift-positions with various driving currents of the bump magnets. We employed the WSM to measure the H⁻ beam profile. It also help us to compare the shift-positions measured by BPM. In this paper, the design and the performance of the BPM is described. In addition, we describe how to compare the shift position.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB071

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TUPVA096

Detection of H⁰ Particles in MEBT2 Chicane of J-PARC Linac

2308

J. Tamura, H. Ao, T. Maruta, A. Miura, T. Morishita, K. Okabe, M. Yoshimoto
JAEA/J-PARC, Tokai-mura, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In the Japan Proton Accelerator Research Complex (J-PARC), H⁰ particles generated by collisions of accelerated H⁻ beams with residual gases are considered as one of the key factors of the residual radiation in the high energy accelerating section of the linac. To diagnose the H⁰ particles, the new beam line for analyzing H⁰ and H⁻ particles was installed in the second medium energy beam transport (MEBT2), which is the matching section from the separated-type drift tube linac (SDTL) to the annular-ring coupled structure linac (ACS). The analysis line consists of four dipole magnets for giving the H⁻ beam chicane orbit, and a wire scanner monitor (WSM) for measuring the horizontal shift of the H⁻ beam. To detect the H⁰ particles, a carbon plate is installed to the WSM. In the beam commissioning, we detected the signals of H⁰ particles penetrating the plate and observed the transition of the signal with various vacuum condition in the SDTL section.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA096

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)