IPAC2017 - List of Authors (Morishita, T.)

Paper	Title	Page
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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THPIK039	Multipactor Problem of J-PARC SDTL	4184
	T. Ito, T. Morishita, J. Tamura JAEA/J-PARC, Tokai-mura, Japan K. Nanmo, T. Sugimura KEK, Ibaraki, Japan
	We have suffered from multipactor problem of some SDTL after the Great East Japan Earthquake. As a designed operating rf power of the SDTL is in the multipactor region, we had to operate at higher power of the designed one. From the result of the simulation and the observation of the SDTL cavity, it became clear that the multipactor occurred on the inner surface of the cavity. We think that one of the cause of the maultipactor is the contamination on the inner surface of the cavity, we performed the cleaning of the inner surface of the cavity by using acetone. The cleaning was very effective and the multipactor region was reduced dramatically or disappeared. The multipactor problem has not occurred since then.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK039
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Paper

Title

Page

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)

THPIK039

Multipactor Problem of J-PARC SDTL

4184

T. Ito, T. Morishita, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
K. Nanmo, T. Sugimura
KEK, Ibaraki, Japan

We have suffered from multipactor problem of some SDTL after the Great East Japan Earthquake. As a designed operating rf power of the SDTL is in the multipactor region, we had to operate at higher power of the designed one. From the result of the simulation and the observation of the SDTL cavity, it became clear that the multipactor occurred on the inner surface of the cavity. We think that one of the cause of the maultipactor is the contamination on the inner surface of the cavity, we performed the cleaning of the inner surface of the cavity by using acetone. The cleaning was very effective and the multipactor region was reduced dramatically or disappeared. The multipactor problem has not occurred since then.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK039

Export •

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