IPAC2019 - List of Authors (Takayanagi, T.)

Paper	Title	Page
MOPGW037	Dynamic Variation of Chromaticity for Beam Instability Mitigation in the 3-GeV RCS of J-PARC	171
	P.K. Saha, H. Harada, H. Hotchi, Y. Shobuda, T. Takayanagi, F. Tamura, Y. Watanabe JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We have studied many other dynamic approaches from that reported in the IPAC 2018 for transverse beam instability mitigation in the presence of strong space charge in the 3-GeV RCS of J-PARC. One of such a method is the introduction of an excess of chromaticity from that of natural chromaticity by reversing the sextupole magnetic fields from the middle of the acceleration cycle. The benifits of this method are twofold. It allows to utilize sextupole for chromaticty correction at lower energy and also mitigate the beam instability at higher energy because of introducing higher chromaticity. We first carried out numerical simulations by using ORBIT code, experimentally verified and then applied for the machine operation. The detail of simulation and measurements results are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW037
About •	paper received ※ 14 May 2019 paper accepted ※ 23 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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TUPMP013	New Design of Vacuum Chambers for Radiation Shield Installation at Beam Injection Area of J-PARC RCS	1255
	J. Kamiya, K. Kotoku, Y. Shobuda, T. Takayanagi, K. Yamamoto, T. Yanagibashi JAEA/J-PARC, Tokai-mura, Japan K. Horino, N. Miki Nippon Advanced Technology Co., Ltd., Tokai, Japan
	One of the issues in the J-PARC 3 GeV rapid cycling synchrotron is the high residual radiation dose around the beam injection point. A radiation shield is necessary to reduce radiation exposure of workers when maintenance is performed there. A space to install the radiation shield should be secured by newly designing a structure of the vacuum chamber at the injection point and the alumina ceramics beam pipes for the shift bump magnets. To make the space for the shield, the chamber is lengthened along the beam line and the cross-sectional shape is changed from circle to rectangle. The displacement and inner stress of the vacuum chamber due to atmospheric pressure was evaluated to be enough small by the calculation. For the ceramics beam pipe’s rf-shield, the damping resistor was effective to reduce the induced modulation voltages by the pulsed magnetic field.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP013
About •	paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS033	J-PARC RCS: High-Order Field Components Inherent in the Injection Bump Magnets and Their Effects on the Circulating Beam During Multi-Turn Injection	2009
	H. Hotchi, H. Harada, T. Takayanagi JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC RCS utilizes four sets of pulsed dipole magnets for the formation of injection orbit bump. The injection bump magnets have a large aspect ratio (gap length/core length), so there are other high-order field components inherent in their magnetic fields in addition to the main dipole component. The high-order field components, which locally exist in the injection section not following the lattice super-periodicity, have a significant influence on the circulating beam during multi-turn injection via the excitation of high-order random betatron resonances. This paper discusses the detailed mechanism of emittance growth and beam loss caused by the high-order field components of the injection bump magnets including its correction scenario on the basis of numerical simulation and experimental results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS033
About •	paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS034	Development of Low Inductance Circuit for Radially Symmetric Circuit	2013
	T. Takayanagi, K. Horino, T. Ueno JAEA/J-PARC, Tokai-mura, Japan
	Radiation symmetric type circuits using semiconductors of SIC-MOSFETs, one of next generation semiconductors, are composed of circuits in which many semiconductor switches are multiplexed in series and in parallel. Since the lengths of all parallel circuits are equal, the output waveform will not be distorted due to timing jitter or level change. This circuit is useful for outputting the waveform of ultrafast short pulse. Therefore, we have developed a circuit that achieves further low inductance by making the power transmission circuit into a double circular ring structure equal to the coaxial shape. Compare the inductance value obtained from the structure and the output waveform. In addition, we compare the calculation and the actual measurement in the actual test and present the verification result of the developed circular ring structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS034
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)

Paper

Title

Page

Dynamic Variation of Chromaticity for Beam Instability Mitigation in the 3-GeV RCS of J-PARC

171

P.K. Saha, H. Harada, H. Hotchi, Y. Shobuda, T. Takayanagi, F. Tamura, Y. Watanabe
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We have studied many other dynamic approaches from that reported in the IPAC 2018 for transverse beam instability mitigation in the presence of strong space charge in the 3-GeV RCS of J-PARC. One of such a method is the introduction of an excess of chromaticity from that of natural chromaticity by reversing the sextupole magnetic fields from the middle of the acceleration cycle. The benifits of this method are twofold. It allows to utilize sextupole for chromaticty correction at lower energy and also mitigate the beam instability at higher energy because of introducing higher chromaticity. We first carried out numerical simulations by using ORBIT code, experimentally verified and then applied for the machine operation. The detail of simulation and measurements results are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW037

About •

paper received ※ 14 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)

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

Export •

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

TUPMP013

New Design of Vacuum Chambers for Radiation Shield Installation at Beam Injection Area of J-PARC RCS

1255

J. Kamiya, K. Kotoku, Y. Shobuda, T. Takayanagi, K. Yamamoto, T. Yanagibashi
JAEA/J-PARC, Tokai-mura, Japan
K. Horino, N. Miki
Nippon Advanced Technology Co., Ltd., Tokai, Japan

One of the issues in the J-PARC 3 GeV rapid cycling synchrotron is the high residual radiation dose around the beam injection point. A radiation shield is necessary to reduce radiation exposure of workers when maintenance is performed there. A space to install the radiation shield should be secured by newly designing a structure of the vacuum chamber at the injection point and the alumina ceramics beam pipes for the shift bump magnets. To make the space for the shield, the chamber is lengthened along the beam line and the cross-sectional shape is changed from circle to rectangle. The displacement and inner stress of the vacuum chamber due to atmospheric pressure was evaluated to be enough small by the calculation. For the ceramics beam pipe’s rf-shield, the damping resistor was effective to reduce the induced modulation voltages by the pulsed magnetic field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP013

About •

paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

TUPTS033

J-PARC RCS: High-Order Field Components Inherent in the Injection Bump Magnets and Their Effects on the Circulating Beam During Multi-Turn Injection

2009

H. Hotchi, H. Harada, T. Takayanagi
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC RCS utilizes four sets of pulsed dipole magnets for the formation of injection orbit bump. The injection bump magnets have a large aspect ratio (gap length/core length), so there are other high-order field components inherent in their magnetic fields in addition to the main dipole component. The high-order field components, which locally exist in the injection section not following the lattice super-periodicity, have a significant influence on the circulating beam during multi-turn injection via the excitation of high-order random betatron resonances. This paper discusses the detailed mechanism of emittance growth and beam loss caused by the high-order field components of the injection bump magnets including its correction scenario on the basis of numerical simulation and experimental results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS033

About •

paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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

TUPTS034

Development of Low Inductance Circuit for Radially Symmetric Circuit

2013

T. Takayanagi, K. Horino, T. Ueno
JAEA/J-PARC, Tokai-mura, Japan

Radiation symmetric type circuits using semiconductors of SIC-MOSFETs, one of next generation semiconductors, are composed of circuits in which many semiconductor switches are multiplexed in series and in parallel. Since the lengths of all parallel circuits are equal, the output waveform will not be distorted due to timing jitter or level change. This circuit is useful for outputting the waveform of ultrafast short pulse. Therefore, we have developed a circuit that achieves further low inductance by making the power transmission circuit into a double circular ring structure equal to the coaxial shape. Compare the inductance value obtained from the structure and the output waveform. In addition, we compare the calculation and the actual measurement in the actual test and present the verification result of the developed circular ring structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS034

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)