IPAC2015 - List of Authors (Maruta, T.)

Paper	Title	Page
THPF043	Preliminary Studies of Laser-assisted H⁻ Stripping at 400 MeV	3795
	P.K. Saha, H. Harada, M. Kinsho, T. Maruta, K. Okabe, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan T.V. Gorlov ORNL, Oak Ridge, Tennessee, USA Y. Irie KEK, Ibaraki, Japan
	Conventional H⁻ stripping injection by using solid stripper foils in high intensity accelerators has many limitations concerning foil scattering beam losses, short lifetime of the foil including unexpected and rapid foil failure due to overheating of the foil. It is not only an issue for reliable machine operation but also for facility maintenance. In the 3-GeV RCS of J-PARC, the residual radiation level is extremely high not only near the injection area but also the used foil itself including the foil holder even at the present operation with one third of the designed 1 MW beam power. As an alternate method, later-assisted stripping of 1 GeV H⁻ beam has been intensively studied at SNS in Oak Ridge. The preparation for the next experiment is underway to demonstrate a three orders of magnitude improvement as compared to the earlier experiment. It is important to extend these studies for the lower H⁻ beam energies. In the same framework as in the SNS, laser stripping for the J-PARC H⁻ beam energy of 400 MeV has been studied in the present work. The real challenges and feasibilities at this lower energy are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF043
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THPF039	Stability Studies for J-PARC Linac Upgrade to 50 mA/400 MeV	3785
	Y. Liu, T. Maruta KEK/JAEA, Ibaraki-Ken, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan M. Ikegami FRIB, East Lansing, Michigan, USA A. Miura JAEA/J-PARC, Tokai-mura, Japan
	J-PARC linac applies the Equi-partitioning (EP) setting as the base-line design. And it is the first machine to adopt this approach at the design stage. EP condition is a natural solution for avoiding emittance exchange between transverse and longitudinal planes. At J-PARC linac it is also possible to explore off-EP settings. One of the motivations could be a lattice with relaxed envelope for mitigating the intra-beam stripping (IBSt) effects in high current H⁻ beam. During and after the energy upgrade in Jan., 2014 and beam current upgrade in Oct., 2014, experiments were carried out to study the stability and emittance evolution for the EP and off-EP settings with high current H⁻ beam at J-PARC linac for better choices of lattice and better understanding.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF039
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THPF040	Recent Progress of the Beam Commissioning in J-PARC Linac	3789
	T. Maruta, Y. Liu KEK/JAEA, Ibaraki-Ken, Japan K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan M. Ikegami FRIB, East Lansing, Michigan, USA A. Miura JAEA/J-PARC, Tokai-mura, Japan
	J-PARC linac iis replaced the front-end in the summer shutdown in year 2014 to extend the maximum peak current to 50 mA from 30 mA. By the combination with the energy upgrade conducted in year 2013, it becomes possible to achieve the design beam energy of 133 kW, which is corresponding to 1 MW at the extraction of 3 GeV Rapid Cycling Sychrotron (RCS). The beam commissioning after the replacement started at Sep./27, and we can successfully accelerate the beam at peak current of 30 mA and 50 mA. In this presentation, we introduce the resent progress of the beam commissioning of the J-PARC linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF040
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Paper

Title

Page

Preliminary Studies of Laser-assisted H⁻ Stripping at 400 MeV

3795

P.K. Saha, H. Harada, M. Kinsho, T. Maruta, K. Okabe, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
T.V. Gorlov
ORNL, Oak Ridge, Tennessee, USA
Y. Irie
KEK, Ibaraki, Japan

Conventional H⁻ stripping injection by using solid stripper foils in high intensity accelerators has many limitations concerning foil scattering beam losses, short lifetime of the foil including unexpected and rapid foil failure due to overheating of the foil. It is not only an issue for reliable machine operation but also for facility maintenance. In the 3-GeV RCS of J-PARC, the residual radiation level is extremely high not only near the injection area but also the used foil itself including the foil holder even at the present operation with one third of the designed 1 MW beam power. As an alternate method, later-assisted stripping of 1 GeV H⁻ beam has been intensively studied at SNS in Oak Ridge. The preparation for the next experiment is underway to demonstrate a three orders of magnitude improvement as compared to the earlier experiment. It is important to extend these studies for the lower H⁻ beam energies. In the same framework as in the SNS, laser stripping for the J-PARC H⁻ beam energy of 400 MeV has been studied in the present work. The real challenges and feasibilities at this lower energy are discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF043

Export •

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

THPF039

Stability Studies for J-PARC Linac Upgrade to 50 mA/400 MeV

3785

Y. Liu, T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

J-PARC linac applies the Equi-partitioning (EP) setting as the base-line design. And it is the first machine to adopt this approach at the design stage. EP condition is a natural solution for avoiding emittance exchange between transverse and longitudinal planes. At J-PARC linac it is also possible to explore off-EP settings. One of the motivations could be a lattice with relaxed envelope for mitigating the intra-beam stripping (IBSt) effects in high current H⁻ beam. During and after the energy upgrade in Jan., 2014 and beam current upgrade in Oct., 2014, experiments were carried out to study the stability and emittance evolution for the EP and off-EP settings with high current H⁻ beam at J-PARC linac for better choices of lattice and better understanding.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF039

Export •

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

THPF040

Recent Progress of the Beam Commissioning in J-PARC Linac

3789

T. Maruta, Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

J-PARC linac iis replaced the front-end in the summer shutdown in year 2014 to extend the maximum peak current to 50 mA from 30 mA. By the combination with the energy upgrade conducted in year 2013, it becomes possible to achieve the design beam energy of 133 kW, which is corresponding to 1 MW at the extraction of 3 GeV Rapid Cycling Sychrotron (RCS). The beam commissioning after the replacement started at Sep./27, and we can successfully accelerate the beam at peak current of 30 mA and 50 mA. In this presentation, we introduce the resent progress of the beam commissioning of the J-PARC linac.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF040

Export •

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