IPAC2019 - List of Authors (Hashimoto, Y.)

Paper	Title	Page
WEPMP010	8 Gev Slow Extraction Beam Test for Muon to Electron Conversion Search Experiment at J-PARC	2322
	M. Tomizawa, Y. Arakaki, Y. Fukao, Y. Hashimoto, Y. Igarashi, T. Kimura, S. Mihara, M. Moritsu, S. Murasugi, R. Muto, H. Nishiguchi, K. Okamura, Y. Shirakabe, K. Ueno, E. Yanaoka KEK, Ibaraki, Japan Y. Fujii Monash University, Faculty of Science, Clayton, Victoria, Australia F. Tamura JAEA/J-PARC, Tokai-mura, Japan
	A muon to electron conversion search experiment (COMET) planned at J-PARC needs 8 GeV bunched proton beams with a continuous 1 MHz pulse structure. In this experiment, an intensity ratio of the residual to the main pulsed beam, which is expressed as extinction, should be less than the level of 10^-10. In RUN78 (Jan. to Feb., 2018), we have succeeded in slow extraction of 8 GeV protons with 7.3×1012 ppp, satisfies the COMET phase-I requirement, and the extinction derived from a timing measurement of secondary particles from the target shows a promising result. A mechanism to explain the measured extinction will be also described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP010
About •	paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPGW030	Beam Profile Monitor for Slow Extracted Beam Using Multi-Layered Graphene at J-PARC	2532
	Y. Hashimoto, Y. Hori, R. Muto, M. Tomizawa, T. Toyama, M. Uota KEK, Tokai, Ibaraki, Japan M. Endo, H. Sakai Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan M. Murakami, K. Murashima, M. Tachibana, A. Tatami KANEKA, Osaka, Japan
	Extracted-beam profiles in slow extraction at J-PARC has been measured by using secondary electrons emitted from a target array made by multi-layered graphen, in real time during spill time of around 2 seconds. The target array consists of 20 ribbons with width of 1 mm, pitch of 2 mm, and thickness of 1.1 micron. Secondary-electron current at each channel is measured by a current amplifier having sensitivity more than 1 pA. These configuration produces useful information for beam dynamics in slow extraction. We have set this monitor at the entrance of a septum magnet, then we can also measure the last few-turns beam with the extracted beam simultaneously. We will discuss about features of this instrument and recent beam study with 51 kW extracted-beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW030
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPGW039	Multi-Ribbon Profile Monitor for High Power Proton Beam at J-PARC MR Abort Line	2561
SUSPFO044	use link to see paper's listing under its alternate paper code
	K. Sato The University of Tokyo, Graduate School of Science, Tokyo, Japan E. Hamada, Y. Hashimoto, S. Igarashi, T. Koseki, Y. Sato KEK, Ibaraki, Japan
	Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), the world-class high intensity proton synchrotron, provides proton beam to two experimental facilities with two extraction modes: Fast extraction (FX) and Slow extraction (SX). The number of protons per pulse (ppp) in MR recorded the world highest value of 2.6×10¹⁴ in the FX mode. Now we are planning to increase the ppp further up to 3.3×10¹⁴ in near future. The beam profile is one of the most important parameters to discuss the high intensity beam dynamics in MR. Monitors using multi-wires / ribbons are effective to measure the beam profile with good accuracy and wide dynamic range. However, they cause significant beam losses by interactions with high-intensity circulating beam in synchrotrons. Recently, we installed new multi-ribbon profile monitor (MRPM) in an abort line in MR. The abort line is one of the extracted beam lines of the FX system. It has a quadrupole doublet which is called Abort Q and transports extracted beam to a beam dump. The FX system can extract the circulating beam in MR with an arbitrary energy. Performing the single-pass measurement with MRPM and changing the transfer matrix by sweeping field strength of Abort Q, the emittance of the extracted beam can be measured. In this paper, we present the design, manufacturing, and results of the first beam test of newly installed MRPM system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW039
About •	paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXXPLS2	Extinction Measurement of J-PARC MR with 8 GeV Proton Beam for the New Muon-to-Electron Conversion Search Experiment - COMET	4372
	H. Nishiguchi, Y. Fukao, Y. Hashimoto, Y. Igarashi, S. Mihara, M. Moritsu, R. Muto, M. Tomizawa, K. Ueno KEK, Tsukuba, Japan Y. Fujii Monash University, Faculty of Science, Clayton, Victoria, Australia P. Sarin Indian Institute of Technology Bombay, Mumbai, India F. Tamura JAEA/J-PARC, Tokai-mura, Japan
	Funding: This work is partially supported by JSPS (Japan Society for the Promotion of Science) : KAKENHI 15K13492 and 16H00876 At J-PARC, extraction tests of a 8GeV pulsed proton beam from Main Ring (MR) have been successfully completed by a team drawn from the Accelerator Laboratory Group and the COherent Muon to Electron Transition (COMET) Experimental Group. The COMET Experiment aims to find new physics beyond the Standard Model by searching for the coherent neutrinoless conversion of a muon to an electron in muonic atoms, so-called mu-e conversion. This requires an extremely clean pulsed beam, and development of this beam plays a key role in the pursuit of the highest level of sensitivity. This successful extraction test is the clearing of a major milestone for the forthcoming experiment. The goal of the extraction tests was to confirm the beam quality under the customized MR operation mode. The J-PARC MR usually accelerates the proton beam (at one bunch per 600ns) up to 30GeV. But in the test, the MR instead accelerates the proton beam (at one bunch per 1.2us) up to 8GeV. The number of protons leaking between proton bunches, so-called EXTINCTION, must be less than one for every 10¹⁰ protons in the bunch. Extraction tests in the customized mode were conducted in January and February 2018 and resulted in many successes. In this test, leakage protons between bunches was successfully reduced below the objective of 10⁻¹⁰ of the number of protons in a bunch. This is a great success to guarantee the quality of proton beam required by COMET experiment. In addition, the time development of proton leakage was also precisely studied with several RF settings which enables us to further improve the extinction. In this paper, the result of extinction measurement and future prospect of beam extinction improvement is presented in addition to the detailed description of customized MR operation.
	Slides FRXXPLS2 [13.427 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS2
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

8 Gev Slow Extraction Beam Test for Muon to Electron Conversion Search Experiment at J-PARC

2322

M. Tomizawa, Y. Arakaki, Y. Fukao, Y. Hashimoto, Y. Igarashi, T. Kimura, S. Mihara, M. Moritsu, S. Murasugi, R. Muto, H. Nishiguchi, K. Okamura, Y. Shirakabe, K. Ueno, E. Yanaoka
KEK, Ibaraki, Japan
Y. Fujii
Monash University, Faculty of Science, Clayton, Victoria, Australia
F. Tamura
JAEA/J-PARC, Tokai-mura, Japan

A muon to electron conversion search experiment (COMET) planned at J-PARC needs 8 GeV bunched proton beams with a continuous 1 MHz pulse structure. In this experiment, an intensity ratio of the residual to the main pulsed beam, which is expressed as extinction, should be less than the level of 10^-10. In RUN78 (Jan. to Feb., 2018), we have succeeded in slow extraction of 8 GeV protons with 7.3×1012 ppp, satisfies the COMET phase-I requirement, and the extinction derived from a timing measurement of secondary particles from the target shows a promising result. A mechanism to explain the measured extinction will be also described in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP010

About •

paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

WEPGW030

Beam Profile Monitor for Slow Extracted Beam Using Multi-Layered Graphene at J-PARC

2532

Y. Hashimoto, Y. Hori, R. Muto, M. Tomizawa, T. Toyama, M. Uota
KEK, Tokai, Ibaraki, Japan
M. Endo, H. Sakai
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
M. Murakami, K. Murashima, M. Tachibana, A. Tatami
KANEKA, Osaka, Japan

Extracted-beam profiles in slow extraction at J-PARC has been measured by using secondary electrons emitted from a target array made by multi-layered graphen, in real time during spill time of around 2 seconds. The target array consists of 20 ribbons with width of 1 mm, pitch of 2 mm, and thickness of 1.1 micron. Secondary-electron current at each channel is measured by a current amplifier having sensitivity more than 1 pA. These configuration produces useful information for beam dynamics in slow extraction. We have set this monitor at the entrance of a septum magnet, then we can also measure the last few-turns beam with the extracted beam simultaneously. We will discuss about features of this instrument and recent beam study with 51 kW extracted-beams.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW030

About •

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

Export •

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

WEPGW039

Multi-Ribbon Profile Monitor for High Power Proton Beam at J-PARC MR Abort Line

2561

SUSPFO044

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

K. Sato
The University of Tokyo, Graduate School of Science, Tokyo, Japan
E. Hamada, Y. Hashimoto, S. Igarashi, T. Koseki, Y. Sato
KEK, Ibaraki, Japan

Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), the world-class high intensity proton synchrotron, provides proton beam to two experimental facilities with two extraction modes: Fast extraction (FX) and Slow extraction (SX). The number of protons per pulse (ppp) in MR recorded the world highest value of 2.6×10¹⁴ in the FX mode. Now we are planning to increase the ppp further up to 3.3×10¹⁴ in near future. The beam profile is one of the most important parameters to discuss the high intensity beam dynamics in MR. Monitors using multi-wires / ribbons are effective to measure the beam profile with good accuracy and wide dynamic range. However, they cause significant beam losses by interactions with high-intensity circulating beam in synchrotrons. Recently, we installed new multi-ribbon profile monitor (MRPM) in an abort line in MR. The abort line is one of the extracted beam lines of the FX system. It has a quadrupole doublet which is called Abort Q and transports extracted beam to a beam dump. The FX system can extract the circulating beam in MR with an arbitrary energy. Performing the single-pass measurement with MRPM and changing the transfer matrix by sweeping field strength of Abort Q, the emittance of the extracted beam can be measured. In this paper, we present the design, manufacturing, and results of the first beam test of newly installed MRPM system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW039

About •

paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

FRXXPLS2

Extinction Measurement of J-PARC MR with 8 GeV Proton Beam for the New Muon-to-Electron Conversion Search Experiment - COMET

4372

H. Nishiguchi, Y. Fukao, Y. Hashimoto, Y. Igarashi, S. Mihara, M. Moritsu, R. Muto, M. Tomizawa, K. Ueno
KEK, Tsukuba, Japan
Y. Fujii
Monash University, Faculty of Science, Clayton, Victoria, Australia
P. Sarin
Indian Institute of Technology Bombay, Mumbai, India
F. Tamura
JAEA/J-PARC, Tokai-mura, Japan

Funding: This work is partially supported by JSPS (Japan Society for the Promotion of Science) : KAKENHI 15K13492 and 16H00876
At J-PARC, extraction tests of a 8GeV pulsed proton beam from Main Ring (MR) have been successfully completed by a team drawn from the Accelerator Laboratory Group and the COherent Muon to Electron Transition (COMET) Experimental Group. The COMET Experiment aims to find new physics beyond the Standard Model by searching for the coherent neutrinoless conversion of a muon to an electron in muonic atoms, so-called mu-e conversion. This requires an extremely clean pulsed beam, and development of this beam plays a key role in the pursuit of the highest level of sensitivity. This successful extraction test is the clearing of a major milestone for the forthcoming experiment. The goal of the extraction tests was to confirm the beam quality under the customized MR operation mode. The J-PARC MR usually accelerates the proton beam (at one bunch per 600ns) up to 30GeV. But in the test, the MR instead accelerates the proton beam (at one bunch per 1.2us) up to 8GeV. The number of protons leaking between proton bunches, so-called EXTINCTION, must be less than one for every 10¹⁰ protons in the bunch. Extraction tests in the customized mode were conducted in January and February 2018 and resulted in many successes. In this test, leakage protons between bunches was successfully reduced below the objective of 10⁻¹⁰ of the number of protons in a bunch. This is a great success to guarantee the quality of proton beam required by COMET experiment. In addition, the time development of proton leakage was also precisely studied with several RF settings which enables us to further improve the extinction. In this paper, the result of extinction measurement and future prospect of beam extinction improvement is presented in addition to the detailed description of customized MR operation.

Slides FRXXPLS2 [13.427 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS2

About •

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

Export •

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