IPAC2018 - List of Authors (Iwashita, Y.)

Paper	Title	Page
MOPML047	Diversified Application of ILC	502
	Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan T. Hayakawa QST, Tokai, Japan N. Kawamura, S. Makimura, K. Mishima, D. Nomura, K. Shimomura, S. Yamamoto, T. Yamazaki KEK, Ibaraki, Japan
	ILC will be a very powerful accelerator complex. It has not only the high power energetic electron beam but also positron and photon beams. In addition to these beams, large cryogenic plants are equipped together with various utility facilities. Some suggestions on the assumption of availability of ILC are offered from various fields. These discussions will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML047
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MOPML048	Design Study of PM Dipole for ILC Damping Ring	505
	Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan N. Terunuma KEK, Ibaraki, Japan
	Dipole magnet using permanent magnet technology is under investigation for ILC cost reduction. It can reduce cost of electricity of coil excitation and cooling water pump, thick electric cabling and water piping, power supply, and their maintenance cost. The structure and the field adjustment scheme will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML048
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WEPAL033	Development of Real-Time Mass Analysis System with Permanent Magnet for Ion Beam	2236
SUSPL051	use link to see paper's listing under its alternate paper code
	Y. Takeuchi, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan
	In order to analyze time variation of the ion species in a pulse, we are developing a mass analysis system that has multiple collector electrodes to detect several ion species simultaneously. Strong permanent magnets can generate 1T magnetic field and the size of the analyzing magnet system can be compact. The detected signals are scanned by a fast multiplexer. The scanning rate is 2 MHz, so that all electrode signals of the 16 channels are scanned in 8 μs period. In this paper, details of the design of the analysis system, and preliminary beam extraction test results with prototype of the system are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL033
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THPAL015	Evaluation of superconducting characteristics on the thin-film structure by NbN and Insulator coatings on pure Nb substrate	3653
	R. Katayama, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan C.Z. Antoine CEA/IRFU, Gif-sur-Yvette, France A. Four CEA/DRF/IRFU, Gif-sur-Yvette, France H. Hayano, T. Kubo, T. Saeki KEK, Ibaraki, Japan H. Ito Sokendai, Ibaraki, Japan R. Ito, T. Nagata ULVAC, Inc, Chiba, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	Funding: The work is supported by JSPS KAKENHI Grant Numbers JP17H04839, JP26600142 and the Collaborative Research Program of ICR Kyoto University (grant 2016-8, 2017-8, 2017-9). In recent years, it is pointed out that the maximum accelerating gradient of a superconducting RF cavity can be pushed up by coating the inner surface of cavity with a multilayer thin-film structure that consists of alternate insulator and superconductive layers. In this structure, the principal parameter that limits the performance of the cavity is the critical magnetic field or effective Hc1 at which vortices start penetrate into the first superconductor layer. We made a sample that has NbN/SiO2 thin-film structure on pure Nb substrate by DC magnetron sputtering method. In this paper, we will report the measurement results of effective Hc1 of the sample by the third-harmonic voltage method.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL015
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THPAL105	Lower Critical Field Measurement System of Thin Film Superconductor	3882
	H. Ito Sokendai, Ibaraki, Japan C.Z. Antoine CEA/IRFU, Gif-sur-Yvette, France A. Four CEA/DRF/IRFU, Gif-sur-Yvette, France H. Hayano, T. Kubo, T. Saeki KEK, Ibaraki, Japan R. Ito, T. Nagata ULVAC, Inc, Chiba, Japan Y. Iwashita, R. Katayama, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	Funding: The work is supported by Japan Society for the Promotion of Science Grant-in-Aid for Young Scientist (A) No.17H04839. Superconducting thin film is the promising technology to increase the performance of SRF cavities. The lower critical field Hc1, which is one of the important physical parameters characterizing a superconducting material, will be enhanced by coating Nb with thin film superconductor such as NbN. To investigate the performance of thin film, we developed the Hc1 measurement system using the third harmonic response of applied AC magnetic field. The measurement system consists of helium cryostat with two of GM refrigerators, sample Cu stage, solenoid coil Cu mount, solenoid coil, temperature sensors, and liquid helium level meter. AC magnetic field is produced by a coil which is driven by function generator and power amplifier at around 1 kHz. In order to control the temperature of the sample stage and coil mount, the depth of thermal anchors attached to the stage and the mount can be moved by the motor. By this temperature control the sample state can be easily transferred from Meissner state to mixed state. So that the measurement is repeated for various applied magnetic field, and the transition curve can be made. In this report, performance of the measurement system is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL105
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THPML120	Development of Coating Technique for Superconducting Multilayered Structure	4954
	R. Ito, T. Nagata ULVAC, Inc, Chiba, Japan H. Hayano, T. Kubo, T. Saeki KEK, Ibaraki, Japan H. Ito Sokendai, Ibaraki, Japan Y. Iwashita, R. Katayama Kyoto ICR, Uji, Kyoto, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	In order to increase the maximum acceleration gradient of SRF cavities, S-I-S (superconductor-insulator-superconductor) multilayered structure theory has been proposed. We focused on NbN which has a higher superconducting transition temperature than Nb. Firstly, we researched the optimal deposition condition for N2 gas reactive sputtering of NbN by using in-house inter-back type DC magnetron sputtering equipment. The critical condition for a thin film with strong crystalline orientation of NbN was identified. The superconducting transition temperature of the NbN thin film, which were coated under the best condition, was over 14 K. Secondly, we tried making S-I-S multilayered samples that was composed of NbN/SiO2/Nb substrate. The coating condition for the NbN layer was determined based on the research results in a single layer. The SiO2 layer was deposited with a film thickness of 30 nm that was theoretically expected to be effective as barrier layer. We applied O2 gas reactive AC magnetron sputtering for coating. In this article, the detailed results of the NbN single layer and multilayer film depositions are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML120
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FRXGBF1	Re-Acceleration of Ultra Cold Muon in J-PARC Muon Facility	5041
	Y. Kondo, K. Hasegawa, T. Morishita JAEA/J-PARC, Tokai-mura, Japan S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko SNU, Seoul, Republic of Korea Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki, M. Yoshida KEK, Ibaraki, Japan N. Hayashizaki RLNR, Tokyo, 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 Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Iwata NIRS, Chiba-shi, Japan R. Kitamura University of Tokyo, Tokyo, Japan S. Li The University of Tokyo, Graduate School of Science, Tokyo, Japan G.P. Razuvaev Budker INP & NSU, Novosibirsk, Russia N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784. J-PARC is developing the reacceleration system of the ultra slow (30 meV) muon (USM) obtained by two-photon laser resonant ionization of muonium atoms. The muon beam thus obtained has low emittance, meeting the requirement for the g-2/EDM experiment. J-PARC E34 experiment aims to measure the muon anomalous magnetic moment (g-2) with a precision of 0.1 ppm and search for EDM with a sensitivity to 10^-21 e cm. The USM's are accelerated to 212 MeV by using a muon dedicated linac to be a ultra cold muon beam. The muon LINAC consists of an RFQ, a inter-digital H-mode DTL, disk and washer coupled cell structures, and disk loaded structures. The ultra-cold muons will have an extremely small transverse momentum spread of 0.1% with a normalized transverse emittance of around 1.5 pi mm-mrad. Proof of the slow muon acceleration scheme is an essential step to realize the world first muon linac. In October 2017, we have succeeded to accelerate slow negative muoniums generated using a simpler muonium source to 89 keV. In this talk, present design of the muon linac and the result of the world first muon acceleration experiment are reported.
	Slides FRXGBF1 [8.373 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBF1
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Diversified Application of ILC

502

Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
T. Hayakawa
QST, Tokai, Japan
N. Kawamura, S. Makimura, K. Mishima, D. Nomura, K. Shimomura, S. Yamamoto, T. Yamazaki
KEK, Ibaraki, Japan

ILC will be a very powerful accelerator complex. It has not only the high power energetic electron beam but also positron and photon beams. In addition to these beams, large cryogenic plants are equipped together with various utility facilities. Some suggestions on the assumption of availability of ILC are offered from various fields. These discussions will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML047

Export •

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

MOPML048

Design Study of PM Dipole for ILC Damping Ring

505

Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
N. Terunuma
KEK, Ibaraki, Japan

Dipole magnet using permanent magnet technology is under investigation for ILC cost reduction. It can reduce cost of electricity of coil excitation and cooling water pump, thick electric cabling and water piping, power supply, and their maintenance cost. The structure and the field adjustment scheme will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML048

Export •

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

WEPAL033

Development of Real-Time Mass Analysis System with Permanent Magnet for Ion Beam

2236

SUSPL051

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

Y. Takeuchi, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan

In order to analyze time variation of the ion species in a pulse, we are developing a mass analysis system that has multiple collector electrodes to detect several ion species simultaneously. Strong permanent magnets can generate 1T magnetic field and the size of the analyzing magnet system can be compact. The detected signals are scanned by a fast multiplexer. The scanning rate is 2 MHz, so that all electrode signals of the 16 channels are scanned in 8 μs period. In this paper, details of the design of the analysis system, and preliminary beam extraction test results with prototype of the system are described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL033

Export •

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

THPAL015

Evaluation of superconducting characteristics on the thin-film structure by NbN and Insulator coatings on pure Nb substrate

3653

R. Katayama, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
C.Z. Antoine
CEA/IRFU, Gif-sur-Yvette, France
A. Four
CEA/DRF/IRFU, Gif-sur-Yvette, France
H. Hayano, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
H. Ito
Sokendai, Ibaraki, Japan
R. Ito, T. Nagata
ULVAC, Inc, Chiba, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

Funding: The work is supported by JSPS KAKENHI Grant Numbers JP17H04839, JP26600142 and the Collaborative Research Program of ICR Kyoto University (grant 2016-8, 2017-8, 2017-9).
In recent years, it is pointed out that the maximum accelerating gradient of a superconducting RF cavity can be pushed up by coating the inner surface of cavity with a multilayer thin-film structure that consists of alternate insulator and superconductive layers. In this structure, the principal parameter that limits the performance of the cavity is the critical magnetic field or effective Hc1 at which vortices start penetrate into the first superconductor layer. We made a sample that has NbN/SiO2 thin-film structure on pure Nb substrate by DC magnetron sputtering method. In this paper, we will report the measurement results of effective Hc1 of the sample by the third-harmonic voltage method.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL015

Export •

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

THPAL105

Lower Critical Field Measurement System of Thin Film Superconductor

3882

H. Ito
Sokendai, Ibaraki, Japan
C.Z. Antoine
CEA/IRFU, Gif-sur-Yvette, France
A. Four
CEA/DRF/IRFU, Gif-sur-Yvette, France
H. Hayano, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
R. Ito, T. Nagata
ULVAC, Inc, Chiba, Japan
Y. Iwashita, R. Katayama, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

Funding: The work is supported by Japan Society for the Promotion of Science Grant-in-Aid for Young Scientist (A) No.17H04839.
Superconducting thin film is the promising technology to increase the performance of SRF cavities. The lower critical field Hc1, which is one of the important physical parameters characterizing a superconducting material, will be enhanced by coating Nb with thin film superconductor such as NbN. To investigate the performance of thin film, we developed the Hc1 measurement system using the third harmonic response of applied AC magnetic field. The measurement system consists of helium cryostat with two of GM refrigerators, sample Cu stage, solenoid coil Cu mount, solenoid coil, temperature sensors, and liquid helium level meter. AC magnetic field is produced by a coil which is driven by function generator and power amplifier at around 1 kHz. In order to control the temperature of the sample stage and coil mount, the depth of thermal anchors attached to the stage and the mount can be moved by the motor. By this temperature control the sample state can be easily transferred from Meissner state to mixed state. So that the measurement is repeated for various applied magnetic field, and the transition curve can be made. In this report, performance of the measurement system is described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL105

Export •

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

THPML120

Development of Coating Technique for Superconducting Multilayered Structure

4954

R. Ito, T. Nagata
ULVAC, Inc, Chiba, Japan
H. Hayano, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
H. Ito
Sokendai, Ibaraki, Japan
Y. Iwashita, R. Katayama
Kyoto ICR, Uji, Kyoto, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

In order to increase the maximum acceleration gradient of SRF cavities, S-I-S (superconductor-insulator-superconductor) multilayered structure theory has been proposed. We focused on NbN which has a higher superconducting transition temperature than Nb. Firstly, we researched the optimal deposition condition for N2 gas reactive sputtering of NbN by using in-house inter-back type DC magnetron sputtering equipment. The critical condition for a thin film with strong crystalline orientation of NbN was identified. The superconducting transition temperature of the NbN thin film, which were coated under the best condition, was over 14 K. Secondly, we tried making S-I-S multilayered samples that was composed of NbN/SiO2/Nb substrate. The coating condition for the NbN layer was determined based on the research results in a single layer. The SiO2 layer was deposited with a film thickness of 30 nm that was theoretically expected to be effective as barrier layer. We applied O2 gas reactive AC magnetron sputtering for coating. In this article, the detailed results of the NbN single layer and multilayer film depositions are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML120

Export •

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

FRXGBF1

Re-Acceleration of Ultra Cold Muon in J-PARC Muon Facility

5041

Y. Kondo, K. Hasegawa, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko
SNU, Seoul, Republic of Korea
Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki, M. Yoshida
KEK, Ibaraki, Japan
N. Hayashizaki
RLNR, Tokyo, 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
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
S. Li
The University of Tokyo, Graduate School of Science, Tokyo, Japan
G.P. Razuvaev
Budker INP & NSU, Novosibirsk, Russia
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
J-PARC is developing the reacceleration system of the ultra slow (30 meV) muon (USM) obtained by two-photon laser resonant ionization of muonium atoms. The muon beam thus obtained has low emittance, meeting the requirement for the g-2/EDM experiment. J-PARC E34 experiment aims to measure the muon anomalous magnetic moment (g-2) with a precision of 0.1 ppm and search for EDM with a sensitivity to 10^-21 e cm. The USM's are accelerated to 212 MeV by using a muon dedicated linac to be a ultra cold muon beam. The muon LINAC consists of an RFQ, a inter-digital H-mode DTL, disk and washer coupled cell structures, and disk loaded structures. The ultra-cold muons will have an extremely small transverse momentum spread of 0.1% with a normalized transverse emittance of around 1.5 pi mm-mrad. Proof of the slow muon acceleration scheme is an essential step to realize the world first muon linac. In October 2017, we have succeeded to accelerate slow negative muoniums generated using a simpler muonium source to 89 keV. In this talk, present design of the muon linac and the result of the world first muon acceleration experiment are reported.

Slides FRXGBF1 [8.373 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBF1

Export •

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