LINAC2018 - List of Authors (Hasegawa, K.)

Paper	Title	Page
MOPO082	Commissioning Status of the Linac for the iBNCT Project	174
	M. Sato, Z. Fang, M.K. Fukuda, Y. Fukui, K. Futatsukawa, Y. Honda, K. Ikegami, H. Kobayashi, C. Kubota, T. Kurihara, T. Miura, T. Miyajima, F. Naito, K. Nanmo, T. Obina, T. Shibata, T. Sugimura, A. Takagi, E. Takasaki KEK, Ibaraki, Japan K. Hasegawa JAEA, Ibaraki-ken, Japan H. Kumada, Y. Matsumoto, Su. Tanaka Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan N. Nagura, T. Ohba Nippon Advanced Technology Co., Ltd., Tokai, Japan T. Onishi Tsukuba University, Ibaraki, Japan T. Ouchi, H. Sakurayama ATOX, Ibaraki, Japan
	Boron neutron capture therapy (BNCT) is one of the particle-beam therapies which use secondary products from a neutron capture on boron medicaments implanted into cancer cells. This has been originally studied with neutrons from nuclear reactors, meanwhile, many activities have been recently projected with accelerator-based neutron generation. In the iBNCT (Ibaraki BNCT) project, the accelerator is consisted with a radio frequency quadrupole (RFQ) and an Alvarez type drift-tube linac (DTL). Protons extracted from an ion source are accelerated up to 3 MeV and 8 MeV, respectively, and bombarded onto a beryllium target to generate neutrons. The design of the linac is based on the J-PARC one, but the most significant difference is the higher duty factor to have a sufficient epithermal neutron flux for BNCT. We have started the commissioning from the end of 2016, and the beam current of 1.3 mA with a repetition of 50 Hz has been achieved with an acceptable stability. Further beam commissioning and reinforcement of the vacuum and cooling water system will be performed toward higher beam current. In this contribution, the current status and future prospects of the linac will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO082
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPO085	Prototype of an Inter-digital H-mode Drift-tube Linac for Muon Linac	180
	Y. Nakazawa, H. Iinuma Ibaraki University, Ibaraki, Japan K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Iwata NIRS, Chiba-shi, Japan N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida KEK, Ibaraki, Japan R. Kitamura, H.Y. Yasuda University of Tokyo, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
	An inter-digital H-mode (IH) drift-tube linac (DTL) is developed for a low velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. In order to achieve higher acceleration efficiency and make cost lower, an alternative phase focusing (APF) scheme is adopted. A prototype with 6 cells of 0.45 m length was manufactured. The prototype accelerates muons from v/c = 0.08 to 0.15 stage. We conducted frequency measurement and bead-pull measurement as a low-power measurement, in order to evaluate the prototype product. In this paper, the results of the low-power measurement for prototype cavity will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO085
About •	paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPO010	Muon Acceleration Test with the RFQ Towards the Development of the Muon Linac	342
SPWR015	use link to see paper's listing under its alternate paper code
	R. Kitamura University of Tokyo, Tokyo, Japan S. Bae, S. Choi, B. Kim SNU, Seoul, Republic of Korea Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, T. Yamazaki KEK, Ibaraki, Japan K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan T. Iijima, Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan K. Ishida RIKEN Nishina Center, Wako, Japan S. Li The University of Tokyo, Graduate School of Science, Tokyo, Japan M. Otani, N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan G.P. Razuvaev Budker INP & NSU, Novosibirsk, Russia
	The muon linac to accelerate muons 212 MeV is planned in order to measure the muon dipole moments precisely in the J-PARC. The muon acceleration with a RF accelerator hasn’t been demonstrated yet in the world. Therefore the muon acceleration test with the RFQ as the feasibility test of the muon linac was demonstrated at the Muon D line in the J-PARC MLF. Conventional muons are cooled with producing ultra-slow muons using the muonium production and the ionization laser for the muon linac. However these apparatuses couldn’t be used because of the limitation of the experimental area in the acceleration test. Therefore the conventional muon was converted to the negative muonium ion (Mu-) with less than 2 keV using the thin aluminum foil target as the easy cooling method. The Mu- was finally accelerated to 90 keV using the RFQ. The accelerated Mu- was selected with a diagnostic beam line and identified with the Time-Of-Flight measurement using a MCP detector. The result of the world’s first muon acceleration test with the RFQ will be reported in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO010
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPO040	Operation Experiences of the J-PARC Linac	774
	K. Hasegawa JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC linac has delivered beam to users since 2008. As of 2018, the linac provides a 40 mA beam at an energy of 400 MeV to the following Rapid Cycling Synchrotron. We have had many issues to impede high availability during the operation. One of them was troubles of high voltage power supply of klystrons. The other category is related to vacuum property in accelerating cavities. The vacuum pumps were reinforced at the RFQ#1 in 2009. The cleaning of the inside surface of some acceleration cavities were performed after the big earthquake in 2011. The cooling water flow rate drop had been a long-time issue. We modified a cooling system to take better flow balances. As a result of these improvement, the availability is approximately 92% or more in these days. However, we have encountered another issue due to some aging components. The operation experiences and availability improvement at the J-PARC linac will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO040
About •	paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPO049	Field Tuning of a Radio-frequency Quadrupole Using Full 3D Modeling	798
	T. Morishita, K. Hasegawa, Y. Kondo, H. Oguri JAEA/J-PARC, Tokai-mura, Japan M. Otani KEK, Ibaraki, Japan
	The radio-frequency quadrupole linac (RFQ) is operating in the frontend of the J-PARC linac to accelerates 50 mA negative hydrogen beams from 0.05 MeV to 3 MeV. As a backup, the spare RFQ has been fabricated in 2018. The vane-voltage ramping is adopted to improve the acceleration efficiency so that the cross-sectional shape is adjusted longitudinally to produce the designed voltage distribution. Then, the three-dimensional cavity models including modulations and cutbacks were created in CST Micro-Wave Studio. The vane-base widths and cutback depths were optimized to produce the desired vane-voltage distribution. In the final tuning, the heights of the stub turners were also determined based on the tuner responses obtained from the full 3D models. In this paper, the detailed design process of the cavity dimensions and the result of the low-power measurements are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO049
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Commissioning Status of the Linac for the iBNCT Project

174

M. Sato, Z. Fang, M.K. Fukuda, Y. Fukui, K. Futatsukawa, Y. Honda, K. Ikegami, H. Kobayashi, C. Kubota, T. Kurihara, T. Miura, T. Miyajima, F. Naito, K. Nanmo, T. Obina, T. Shibata, T. Sugimura, A. Takagi, E. Takasaki
KEK, Ibaraki, Japan
K. Hasegawa
JAEA, Ibaraki-ken, Japan
H. Kumada, Y. Matsumoto, Su. Tanaka
Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
N. Nagura, T. Ohba
Nippon Advanced Technology Co., Ltd., Tokai, Japan
T. Onishi
Tsukuba University, Ibaraki, Japan
T. Ouchi, H. Sakurayama
ATOX, Ibaraki, Japan

Boron neutron capture therapy (BNCT) is one of the particle-beam therapies which use secondary products from a neutron capture on boron medicaments implanted into cancer cells. This has been originally studied with neutrons from nuclear reactors, meanwhile, many activities have been recently projected with accelerator-based neutron generation. In the iBNCT (Ibaraki BNCT) project, the accelerator is consisted with a radio frequency quadrupole (RFQ) and an Alvarez type drift-tube linac (DTL). Protons extracted from an ion source are accelerated up to 3 MeV and 8 MeV, respectively, and bombarded onto a beryllium target to generate neutrons. The design of the linac is based on the J-PARC one, but the most significant difference is the higher duty factor to have a sufficient epithermal neutron flux for BNCT. We have started the commissioning from the end of 2016, and the beam current of 1.3 mA with a repetition of 50 Hz has been achieved with an acceptable stability. Further beam commissioning and reinforcement of the vacuum and cooling water system will be performed toward higher beam current. In this contribution, the current status and future prospects of the linac will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO082

About •

paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

Export •

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

MOPO085

Prototype of an Inter-digital H-mode Drift-tube Linac for Muon Linac

180

Y. Nakazawa, H. Iinuma
Ibaraki University, Ibaraki, Japan
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida
KEK, Ibaraki, Japan
R. Kitamura, H.Y. Yasuda
University of Tokyo, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan

An inter-digital H-mode (IH) drift-tube linac (DTL) is developed for a low velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. In order to achieve higher acceleration efficiency and make cost lower, an alternative phase focusing (APF) scheme is adopted. A prototype with 6 cells of 0.45 m length was manufactured. The prototype accelerates muons from v/c = 0.08 to 0.15 stage. We conducted frequency measurement and bead-pull measurement as a low-power measurement, in order to evaluate the prototype product. In this paper, the results of the low-power measurement for prototype cavity will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO085

About •

paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

Export •

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

TUPO010

Muon Acceleration Test with the RFQ Towards the Development of the Muon Linac

342

SPWR015

use link to see paper's listing under its alternate paper code

R. Kitamura
University of Tokyo, Tokyo, Japan
S. Bae, S. Choi, B. Kim
SNU, Seoul, Republic of Korea
Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
S. Li
The University of Tokyo, Graduate School of Science, Tokyo, Japan
M. Otani, N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
G.P. Razuvaev
Budker INP & NSU, Novosibirsk, Russia

The muon linac to accelerate muons 212 MeV is planned in order to measure the muon dipole moments precisely in the J-PARC. The muon acceleration with a RF accelerator hasn’t been demonstrated yet in the world. Therefore the muon acceleration test with the RFQ as the feasibility test of the muon linac was demonstrated at the Muon D line in the J-PARC MLF. Conventional muons are cooled with producing ultra-slow muons using the muonium production and the ionization laser for the muon linac. However these apparatuses couldn’t be used because of the limitation of the experimental area in the acceleration test. Therefore the conventional muon was converted to the negative muonium ion (Mu-) with less than 2 keV using the thin aluminum foil target as the easy cooling method. The Mu- was finally accelerated to 90 keV using the RFQ. The accelerated Mu- was selected with a diagnostic beam line and identified with the Time-Of-Flight measurement using a MCP detector. The result of the world’s first muon acceleration test with the RFQ will be reported in this presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO010

About •

paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

Export •

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

THPO040

Operation Experiences of the J-PARC Linac

774

K. Hasegawa
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC linac has delivered beam to users since 2008. As of 2018, the linac provides a 40 mA beam at an energy of 400 MeV to the following Rapid Cycling Synchrotron. We have had many issues to impede high availability during the operation. One of them was troubles of high voltage power supply of klystrons. The other category is related to vacuum property in accelerating cavities. The vacuum pumps were reinforced at the RFQ#1 in 2009. The cleaning of the inside surface of some acceleration cavities were performed after the big earthquake in 2011. The cooling water flow rate drop had been a long-time issue. We modified a cooling system to take better flow balances. As a result of these improvement, the availability is approximately 92% or more in these days. However, we have encountered another issue due to some aging components. The operation experiences and availability improvement at the J-PARC linac will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO040

About •

paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

Export •

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

THPO049

Field Tuning of a Radio-frequency Quadrupole Using Full 3D Modeling

798

T. Morishita, K. Hasegawa, Y. Kondo, H. Oguri
JAEA/J-PARC, Tokai-mura, Japan
M. Otani
KEK, Ibaraki, Japan

The radio-frequency quadrupole linac (RFQ) is operating in the frontend of the J-PARC linac to accelerates 50 mA negative hydrogen beams from 0.05 MeV to 3 MeV. As a backup, the spare RFQ has been fabricated in 2018. The vane-voltage ramping is adopted to improve the acceleration efficiency so that the cross-sectional shape is adjusted longitudinally to produce the designed voltage distribution. Then, the three-dimensional cavity models including modulations and cutbacks were created in CST Micro-Wave Studio. The vane-base widths and cutback depths were optimized to produce the desired vane-voltage distribution. In the final tuning, the heights of the stub turners were also determined based on the tuner responses obtained from the full 3D models. In this paper, the detailed design process of the cavity dimensions and the result of the low-power measurements are described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO049

About •

paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

Export •

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