IPAC2019 - List of Authors (Otani, M.)

Paper	Title	Page
MOPTS048	Longitudinal Measurements and Beam Tuning in the J-PARC Linac MEBT1	968
	M. Otani J-PARC, KEK & JAEA, Ibaraki-ken, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan K. Hirano, Y. Kondo, A. Miura, H. Oguri JAEA/J-PARC, Tokai-mura, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan
	J-PARC linac is operated with design peak current of 50 mA from October 2018. Recently we succeeded in establishing longitudinal measurement at MEBT1, with which the beam matching is being studied in MEBT1. In this poster, recent measurements and beam tuning results in MEBT1 will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS048
About •	paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPRB117	Disk and Washer Coupled Cavity Linac Design and Cold-Model for Muon Linac	1924
	M. Otani, N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan K. Futatsukawa, T. Mibe, F. Naito KEK, Ibaraki, Japan K. Hasegawa, T. Ito, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan R. Kitamura University of Tokyo, Tokyo, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707. A disk and washer (DAW) coupled cavity linac (CCL) has been developed for a middle velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.3 to 0.7 at an operational frequency of 1296 MHz. In this poster, the cavity designs, beam dynamics designs, and the cold-model measurements will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB117
About •	paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOZZPLM2	A Bunch Structure Measurement of Muons Accelerated by RFQ Using a Longitudinal Beam-Profile Monitor With High Time Resolution	37
SUSPFO046	use link to see paper's listing under its alternate paper code
	Y. Sue, K. Inami Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, T. Yamazaki KEK, Ibaraki, Japan K. Hasegawa, R. Kitamura, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima KMI, Nagoya, AIchi Prefecture, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan K. Ishida RIKEN Nishina Center, Wako, Japan Y. Kondo JAEA, Ibaraki-ken, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Takeuchi Kyoto ICR, Uji, Kyoto, Japan T. Ushizawa Sokendai, Ibaraki, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan M. Yotsuzuka Nagoya University, Nagoya, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226. J-PARC E34 experiment intends to measure the anomalous magnetic moment and electric dipole moment of muon precisely by a different way from the previous experiment. In this experiment, a low-emittance muon beam is provided using the muons with the thermal energy and the four-stage linac. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured last year. As one of the remaining issues for the beam-diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the micro-channel plate is under development. The time resolution aims to be around 30 to 40 ps corresponding to 1 % of a period of an operation frequency of the accelerator, which is 324 MHz. On November 2018, the bunch structure of accelerated muons of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The latest analysis result of this measurement will be reported in this poster.
	Slides MOZZPLM2 [2.618 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM2
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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MOPRB017	Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment	606
SUSPFO041	use link to see paper's listing under its alternate paper code
	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
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP18H03707, JP16H03987, and JP16J07784. An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB017
About •	paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPRB018	Conceptual Design of Negative-Muon Decelerator for Material Science	610
	C. Ohmori, M. Otani, K. Shimomura KEK, Tokai, Ibaraki, Japan T. Takayanagi JAEA/J-PARC, Tokai-mura, Japan
	In 2018, a Negative-Muon Spin Rotation and Relaxation technique was developed in J-PARC Material and Life Science Facility. It is a novel scheme to investigate the motion of hydrogens in the chemicals and materials. To study small samples, the surface of materials and thin foils, a low energy negative muon beam is required. To decelerate intense 300-keV muons to 15-keV, we propose a system which consists of pulse generators and multi-gap induction decelerators. In this design, an inductive adder scheme is considered to use for the high voltage pulse source. High impedance magnetic alloy ring cores will be loaded in the decelerator cells. The high impedance cores which have much larger size than those for public use were developed for J-PARC RF systems and used for many applications including CERN booster RF, anti-proton deceleration and medical accelerator. In this paper, we present a conceptual design of muon deceleration system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB018
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB023	Design of the Wien-Filter Type Spin Rotator for the Low-Emittance Muon Beam	622
SUSPFO050	use link to see paper's listing under its alternate paper code
	H.Y. Yasuda University of Tokyo, Tokyo, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan N. Kawamura, T. Mibe, M. Otani KEK, Ibaraki, Japan Y. Kondo JAEA/J-PARC, Tokai-mura, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Numbers JP18J22129, JP18H03707. Muon linac is developed for the muon g-2/EDM experiment at J-PARC. In this experiment, ultra slow muon is accelerated to a momentum of 300 MeV/c with the four linac structures. This scheme offers new opportunity for precise measurements; it enables us to reverse muon polarization at early stage of acceleration. The reversal of polarization is a common method of precision polarization measurements as it can be used to identify or reduce systematic uncertainties dependent on time. It is necessary to accelerate muons and flip its spin without substantial emittance growth for the experimental requirement. As one of the candidates for our spin rotator, we are developing the Wien-filter type. In this poster, the design of the Wien-filter type spin rotator for the low emittance muon beam will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB023
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS046	Upgrade of the 3-MeV LINAC for Testing of Accelerator Components at J-PARC	960
	Y. Kondo, K. Hirano, T. Ito, N. Kikuzawa, R. Kitamura, T. Morishita, H. Oguri, K. Ohkoshi, S. Shinozaki, K. Shinto JAEA/J-PARC, Tokai-mura, Japan Z. Fang, Y. Fukui, K. Futatsukawa, K. Ikegami, T. Miyao, K. Nanmo, M. Otani, T. Shibata KEK, Ibaraki, Japan T. Hori, Y. Nemoto, Y. Sato Nippon Advanced Technology Co., Ltd., Tokai, Japan T. Ishiyama, Y. Sawabe Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan Y. Ito Total Saport System Corp., Naka-gun, Ibaraki, Japan Y. Kato Total Support Systems Corporation, Tokai-mura, Naka-gun, Ibaraki, Japan F. Kobayashi ULVAC Human Relations, Ltd., Kanagawa, Japan D. Takahashi, R. Tasaki KIS, Ibaraki, Japan
	We are now upgrading a 3-MeV linac at J-PARC. The old 30-mA RFQ is replaced by a spare one of the J-PARC 50-mA RFQ. The ion source is same as the J-PARC linac’s, therefore, the peak beam current is upgraded from 30 mA to 50 mA. This 3-MeV linac will be used for development of various accelerator components, such as beam dyagnostics devices, laser charge exchange equipments, new MEBT buncher, and so on. In this paper, present status of this 3-MeV test linac is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS046
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS049	The First Replacement of the RF Window of the ACS Cavity	971
	J. Tamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan F. Naito, M. Otani KEK, Tokai, Ibaraki, Japan Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	In 2013, the Annular-ring Coupled Structure (ACS) cavities were installed to the Japan Proton Accelerator Research Complex (J-PARC) linac. Since then, the ACS cavities have been stably running. Although any serious problem induced by the ACS RF window has not yet observed, we decided to replace the RF window of one ACS cavity, which is the eighteenth accelerating cavity in the order of beam energy (ACS18), by the newly manufactured one. The major motivations of the replacement are to check the surface condition of the RF window which have been under operation for nearly five years and to confirm the availability of the newly manufactured RF window. By making use of the summer maintenance period of 2018, we carried out the replacement. This was the first experience for us to replace the RF window installed to the ACS cavity in the linac accelerator tunnel. As for the removed RF window, there was no any abnormal warning found with the visual examination. At the starting up of the cavity’s operation after the maintenance period, we investigated how much time would be required for an RF conditioning. It took around fifty hours so that the peak RF power including the beam loading is stably input to the cavity through the new RF window. The ACS cavity with the new RF window is now stably operating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS049
About •	paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS050	VSWR Adjustment for ACS Cavity in J-PARC LINAC	974
	J. Tamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan F. Naito, M. Otani KEK, Tokai, Ibaraki, Japan Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	In the Japan Proton Accelerator Research Complex (J-PARC) linac, negative hydrogen beams are accelerated from 190 MeV to 400 MeV by twenty-one Annular-ring Coupled Structure (ACS) accelerating cavities. The input coupler of the ACS high-beta cavity, which is the 21st accelerating cavity (ACS21) in the order of beam acceleration, had a comparatively larger value of the Voltage Standing Wave Ratio (VSWR) than those of the other ACS cavities. To adjust the VSWR of the ACS21, we designed and fabricated a rectangular waveguide with a capacitive iris which conduces to a better matching between the cavity and the waveguide. In the 2018 summer maintenance period, we installed the newly fabricated waveguide to the ACS21 in the position between the input coupler and the RF window. Consequently, the VSWR of the ACS21 was successfully decreased to the target value which leads to the critical coupling under the nominal accelerating condition with 50-mA peak beam current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS050
About •	paper received ※ 01 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUXXPLS2	Negative Muonium Ion Production With a C12A7 Electride Film	1175
	M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, K. Shimomura, T. Yamazaki KEK, Ibaraki, Japan K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima, Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan K. Inami, M. Yotsuzuka Nagoya University, Nagoya, Japan K. Ishida RIKEN Nishina Center, Wako, Japan R. Kitamura, H.Y. Yasuda University of Tokyo, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Funding: This work was supported by OSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707. Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H⁻ formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented.
	Slides TUXXPLS2 [2.680 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS2
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPTS027	Progress of J-PARC LINAC Commissioning	1990
	Y. Liu KEK/JAEA, Ibaraki-Ken, Japan Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata KEK, Tokai, Ibaraki, Japan T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027
About •	paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPGW033	Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire	2543
	R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan K. Futatsukawa, T. Miyao, M. Otani KEK, Tokai, Ibaraki, Japan S. Kosaka, Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPGW042	Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment	2571
SUSPFO052	use link to see paper's listing under its alternate paper code
	M. Yotsuzuka, K. Inami Nagoya University, Nagoya, Japan K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki KEK, Ibaraki, Japan K. Hasegawa, R. Kitamura, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima, Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan T. Iijima KMI, Nagoya, AIchi Prefecture, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan Y. Kondo JAEA, Ibaraki-ken, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226. The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW042
About •	paper received ※ 30 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

Longitudinal Measurements and Beam Tuning in the J-PARC Linac MEBT1

968

M. Otani
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
K. Hirano, Y. Kondo, A. Miura, H. Oguri
JAEA/J-PARC, Tokai-mura, Japan
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan

J-PARC linac is operated with design peak current of 50 mA from October 2018. Recently we succeeded in establishing longitudinal measurement at MEBT1, with which the beam matching is being studied in MEBT1. In this poster, recent measurements and beam tuning results in MEBT1 will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS048

About •

paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPRB117

Disk and Washer Coupled Cavity Linac Design and Cold-Model for Muon Linac

1924

M. Otani, N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
K. Futatsukawa, T. Mibe, F. Naito
KEK, Ibaraki, Japan
K. Hasegawa, T. Ito, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan

Funding: This work was supported by JSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707.
A disk and washer (DAW) coupled cavity linac (CCL) has been developed for a middle velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.3 to 0.7 at an operational frequency of 1296 MHz. In this poster, the cavity designs, beam dynamics designs, and the cold-model measurements will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB117

About •

paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOZZPLM2

A Bunch Structure Measurement of Muons Accelerated by RFQ Using a Longitudinal Beam-Profile Monitor With High Time Resolution

37

SUSPFO046

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

Y. Sue, K. Inami
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, R. Kitamura, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Takeuchi
Kyoto ICR, Uji, Kyoto, Japan
T. Ushizawa
Sokendai, Ibaraki, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan
M. Yotsuzuka
Nagoya University, Nagoya, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226.
J-PARC E34 experiment intends to measure the anomalous magnetic moment and electric dipole moment of muon precisely by a different way from the previous experiment. In this experiment, a low-emittance muon beam is provided using the muons with the thermal energy and the four-stage linac. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured last year. As one of the remaining issues for the beam-diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the micro-channel plate is under development. The time resolution aims to be around 30 to 40 ps corresponding to 1 % of a period of an operation frequency of the accelerator, which is 324 MHz. On November 2018, the bunch structure of accelerated muons of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The latest analysis result of this measurement will be reported in this poster.

Slides MOZZPLM2 [2.618 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM2

About •

paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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MOPRB017

Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment

606

SUSPFO041

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

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

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP18H03707, JP16H03987, and JP16J07784.
An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB017

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paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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MOPRB018

Conceptual Design of Negative-Muon Decelerator for Material Science

610

C. Ohmori, M. Otani, K. Shimomura
KEK, Tokai, Ibaraki, Japan
T. Takayanagi
JAEA/J-PARC, Tokai-mura, Japan

In 2018, a Negative-Muon Spin Rotation and Relaxation technique was developed in J-PARC Material and Life Science Facility. It is a novel scheme to investigate the motion of hydrogens in the chemicals and materials. To study small samples, the surface of materials and thin foils, a low energy negative muon beam is required. To decelerate intense 300-keV muons to 15-keV, we propose a system which consists of pulse generators and multi-gap induction decelerators. In this design, an inductive adder scheme is considered to use for the high voltage pulse source. High impedance magnetic alloy ring cores will be loaded in the decelerator cells. The high impedance cores which have much larger size than those for public use were developed for J-PARC RF systems and used for many applications including CERN booster RF, anti-proton deceleration and medical accelerator. In this paper, we present a conceptual design of muon deceleration system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB018

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPRB023

Design of the Wien-Filter Type Spin Rotator for the Low-Emittance Muon Beam

622

SUSPFO050

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H.Y. Yasuda
University of Tokyo, Tokyo, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
N. Kawamura, T. Mibe, M. Otani
KEK, Ibaraki, Japan
Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan

Funding: This work was supported by JSPS KAKENHI Grant Numbers JP18J22129, JP18H03707.
Muon linac is developed for the muon g-2/EDM experiment at J-PARC. In this experiment, ultra slow muon is accelerated to a momentum of 300 MeV/c with the four linac structures. This scheme offers new opportunity for precise measurements; it enables us to reverse muon polarization at early stage of acceleration. The reversal of polarization is a common method of precision polarization measurements as it can be used to identify or reduce systematic uncertainties dependent on time. It is necessary to accelerate muons and flip its spin without substantial emittance growth for the experimental requirement. As one of the candidates for our spin rotator, we are developing the Wien-filter type. In this poster, the design of the Wien-filter type spin rotator for the low emittance muon beam will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB023

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS046

Upgrade of the 3-MeV LINAC for Testing of Accelerator Components at J-PARC

960

Y. Kondo, K. Hirano, T. Ito, N. Kikuzawa, R. Kitamura, T. Morishita, H. Oguri, K. Ohkoshi, S. Shinozaki, K. Shinto
JAEA/J-PARC, Tokai-mura, Japan
Z. Fang, Y. Fukui, K. Futatsukawa, K. Ikegami, T. Miyao, K. Nanmo, M. Otani, T. Shibata
KEK, Ibaraki, Japan
T. Hori, Y. Nemoto, Y. Sato
Nippon Advanced Technology Co., Ltd., Tokai, Japan
T. Ishiyama, Y. Sawabe
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
Y. Ito
Total Saport System Corp., Naka-gun, Ibaraki, Japan
Y. Kato
Total Support Systems Corporation, Tokai-mura, Naka-gun, Ibaraki, Japan
F. Kobayashi
ULVAC Human Relations, Ltd., Kanagawa, Japan
D. Takahashi, R. Tasaki
KIS, Ibaraki, Japan

We are now upgrading a 3-MeV linac at J-PARC. The old 30-mA RFQ is replaced by a spare one of the J-PARC 50-mA RFQ. The ion source is same as the J-PARC linac’s, therefore, the peak beam current is upgraded from 30 mA to 50 mA. This 3-MeV linac will be used for development of various accelerator components, such as beam dyagnostics devices, laser charge exchange equipments, new MEBT buncher, and so on. In this paper, present status of this 3-MeV test linac is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS046

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paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPTS049

The First Replacement of the RF Window of the ACS Cavity

971

J. Tamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
F. Naito, M. Otani
KEK, Tokai, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In 2013, the Annular-ring Coupled Structure (ACS) cavities were installed to the Japan Proton Accelerator Research Complex (J-PARC) linac. Since then, the ACS cavities have been stably running. Although any serious problem induced by the ACS RF window has not yet observed, we decided to replace the RF window of one ACS cavity, which is the eighteenth accelerating cavity in the order of beam energy (ACS18), by the newly manufactured one. The major motivations of the replacement are to check the surface condition of the RF window which have been under operation for nearly five years and to confirm the availability of the newly manufactured RF window. By making use of the summer maintenance period of 2018, we carried out the replacement. This was the first experience for us to replace the RF window installed to the ACS cavity in the linac accelerator tunnel. As for the removed RF window, there was no any abnormal warning found with the visual examination. At the starting up of the cavity’s operation after the maintenance period, we investigated how much time would be required for an RF conditioning. It took around fifty hours so that the peak RF power including the beam loading is stably input to the cavity through the new RF window. The ACS cavity with the new RF window is now stably operating.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS049

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paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS050

VSWR Adjustment for ACS Cavity in J-PARC LINAC

974

J. Tamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
F. Naito, M. Otani
KEK, Tokai, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In the Japan Proton Accelerator Research Complex (J-PARC) linac, negative hydrogen beams are accelerated from 190 MeV to 400 MeV by twenty-one Annular-ring Coupled Structure (ACS) accelerating cavities. The input coupler of the ACS high-beta cavity, which is the 21st accelerating cavity (ACS21) in the order of beam acceleration, had a comparatively larger value of the Voltage Standing Wave Ratio (VSWR) than those of the other ACS cavities. To adjust the VSWR of the ACS21, we designed and fabricated a rectangular waveguide with a capacitive iris which conduces to a better matching between the cavity and the waveguide. In the 2018 summer maintenance period, we installed the newly fabricated waveguide to the ACS21 in the position between the input coupler and the RF window. Consequently, the VSWR of the ACS21 was successfully decreased to the target value which leads to the critical coupling under the nominal accelerating condition with 50-mA peak beam current.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS050

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paper received ※ 01 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUXXPLS2

Negative Muonium Ion Production With a C12A7 Electride Film

1175

M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, K. Shimomura, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
K. Inami, M. Yotsuzuka
Nagoya University, Nagoya, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
R. Kitamura, H.Y. Yasuda
University of Tokyo, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work was supported by OSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707.
Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H⁻ formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented.

Slides TUXXPLS2 [2.680 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS2

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS027

Progress of J-PARC LINAC Commissioning

1990

Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
Z. Fang, K. Futatsukawa, T. Miyao, M. Otani, T. Shibata
KEK, Tokai, Ibaraki, Japan
T. Ito, A. Miura, T. Morishita, K. Moriya, K. Okabe, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027

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paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW033

Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire

2543

R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao, M. Otani
KEK, Tokai, Ibaraki, Japan
S. Kosaka, Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW042

Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment

2571

SUSPFO052

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M. Yotsuzuka, K. Inami
Nagoya University, Nagoya, Japan
K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki
KEK, Ibaraki, Japan
K. Hasegawa, R. Kitamura, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226.
The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW042

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paper received ※ 30 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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