HB2023 - List of Authors (Saha, P.K.)

Paper	Title	Page
TUC3I3	Laser Stripping of H⁻ Beam	141
	T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A.R. Oguz ORNL, Oak Ridge, Tennessee, USA N.J. Evans ORNL RAD, Oak Ridge, Tennessee, USA P.K. Saha JAEA/J-PARC, Tokai-mura, Japan
	Basic principles of laser assisted charge exchange injection for H⁻ ion andH⁰ beams are presented. Theoretical aspects of electromagnetic interaction of laser with hydrogen atom and H⁻ ions are discussed. Laser excitation, photoionizatio and interaction of atoms and ions with a strong electro-magnetic field are discussed and compared. Different techniques of LACE for stripping of high current stochastic beams are presented. The optimum parameters of LACE are estimated and compared for various ion beam energies. Experimental development of laser stripping at the SNS are reviewed. Future plans of LACE at the SNS and J-PARC are discussed.
	Slides TUC3I3 [1.790 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I3
About •	Received ※ 04 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUA4I2	1-MW Beam Operation at J-PARC RCS with Minimum Beam Loss	147
	P.K. Saha, H. Harada, H. Hotchi, K. Okabe, H. Okita, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The 3-GeV RCS of J-PARC now operates at high-intensity to nearly the designed 1 MW beam. The beam loss and the corresponding residual radiation is one of the key limitations against beam intensity ramp up. Recently, by a series of beam studies and feedback from numerical simulations, we have well mitigated the beam loss to a minimum level and also reduced the beam emittances for beam operation to the spallation neutron source as well as to the main ring. The residual beam loss at the designed 1 MW beam power occurs mostly due to the unavoidable foil scattering beam loss during multi-turn injection, while other beam loss sources have been well mitigated to realize a stable and higher availability beam operation at a nearly 1 MW beam power.
	Slides TUA4I2 [2.303 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4I2
About •	Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC4I1	A Kicker Impedance Reduction Scheme with Diode Stack and Resistor at the RCS in J-PARC	162
	Y. Shobuda, H. Harada, P.K. Saha, T. Takayanagi, F. Tamura, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto JAEA/J-PARC, Tokai-mura, Japan
	At the 3-GeV Rapid Cycling Synchrotron (RCS) within the Japan Proton Accelerator Research Complex (J-PARC), kicker impedance causes beam instability. A 1-MW beam with a large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) by suppressing beam instabilities without the need for a transverse feedback system¿simply by turning off the sextuple magnets. However, we require other high-intensity and high-quality beams with smaller emittances for the Main Ring (MR). To address this, we proposed a scheme for suppressing the kicker impedance using a diode stack and resistors, which effectively reduces beam instability. Importantly, these devices have a negligible effect on the extracted beam from the RCS.
	Slides TUC4I1 [2.713 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I1
About •	Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEC3C1	Beyond 1-MW Scenario in J-Parc Rapid-Cycling Synchrotron	270
	K. Yamamoto, T. Morishita, K. Moriya, H. Okita, P.K. Saha, Y. Shobuda, F. Tamura, I. Yamada, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The 3-GeV rapid cycling synchrotron at the Ja-pan Pro-ton Accelerator Research Complex was designed to provid 1-MW proton beams to the Material and Life Sci-ence Experimental Facility and Main Ring. Thanks to the improvement works of the accelerator system, we success-fully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce require-ment of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also contin-ued study to achieve more than 2 MW beam in J-PARC RCS.
	Slides WEC3C1 [2.787 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C1
About •	Received ※ 25 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRA2I3	Summary of the Working Group C on Accelerator Systems	670
	S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom H. Huang BNL, Upton, New York, USA P.K. Saha JAEA/J-PARC, Tokai-mura, Japan
	This is a summary of the presentations and discussions of the Accelerator System working group at the 68th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams.
	Slides FRA2I3 [0.262 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I3
About •	Received ※ 22 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 15 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Laser Stripping of H⁻ Beam

141

T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A.R. Oguz
ORNL, Oak Ridge, Tennessee, USA
N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA
P.K. Saha
JAEA/J-PARC, Tokai-mura, Japan

Basic principles of laser assisted charge exchange injection for H⁻ ion andH⁰ beams are presented. Theoretical aspects of electromagnetic interaction of laser with hydrogen atom and H⁻ ions are discussed. Laser excitation, photoionizatio and interaction of atoms and ions with a strong electro-magnetic field are discussed and compared. Different techniques of LACE for stripping of high current stochastic beams are presented. The optimum parameters of LACE are estimated and compared for various ion beam energies. Experimental development of laser stripping at the SNS are reviewed. Future plans of LACE at the SNS and J-PARC are discussed.

Slides TUC3I3 [1.790 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I3

About •

Received ※ 04 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023

Cite •

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

TUA4I2

1-MW Beam Operation at J-PARC RCS with Minimum Beam Loss

147

P.K. Saha, H. Harada, H. Hotchi, K. Okabe, H. Okita, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV RCS of J-PARC now operates at high-intensity to nearly the designed 1 MW beam. The beam loss and the corresponding residual radiation is one of the key limitations against beam intensity ramp up. Recently, by a series of beam studies and feedback from numerical simulations, we have well mitigated the beam loss to a minimum level and also reduced the beam emittances for beam operation to the spallation neutron source as well as to the main ring. The residual beam loss at the designed 1 MW beam power occurs mostly due to the unavoidable foil scattering beam loss during multi-turn injection, while other beam loss sources have been well mitigated to realize a stable and higher availability beam operation at a nearly 1 MW beam power.

Slides TUA4I2 [2.303 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4I2

About •

Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023

Cite •

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

TUC4I1

A Kicker Impedance Reduction Scheme with Diode Stack and Resistor at the RCS in J-PARC

162

Y. Shobuda, H. Harada, P.K. Saha, T. Takayanagi, F. Tamura, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan

At the 3-GeV Rapid Cycling Synchrotron (RCS) within the Japan Proton Accelerator Research Complex (J-PARC), kicker impedance causes beam instability. A 1-MW beam with a large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) by suppressing beam instabilities without the need for a transverse feedback system¿simply by turning off the sextuple magnets. However, we require other high-intensity and high-quality beams with smaller emittances for the Main Ring (MR). To address this, we proposed a scheme for suppressing the kicker impedance using a diode stack and resistors, which effectively reduces beam instability. Importantly, these devices have a negligible effect on the extracted beam from the RCS.

Slides TUC4I1 [2.713 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I1

About •

Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023

Cite •

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

WEC3C1

Beyond 1-MW Scenario in J-Parc Rapid-Cycling Synchrotron

270

K. Yamamoto, T. Morishita, K. Moriya, H. Okita, P.K. Saha, Y. Shobuda, F. Tamura, I. Yamada, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV rapid cycling synchrotron at the Ja-pan Pro-ton Accelerator Research Complex was designed to provid 1-MW proton beams to the Material and Life Sci-ence Experimental Facility and Main Ring. Thanks to the improvement works of the accelerator system, we success-fully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce require-ment of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also contin-ued study to achieve more than 2 MW beam in J-PARC RCS.

Slides WEC3C1 [2.787 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C1

About •

Received ※ 25 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023

Cite •

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

FRA2I3

Summary of the Working Group C on Accelerator Systems

670

S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
H. Huang
BNL, Upton, New York, USA
P.K. Saha
JAEA/J-PARC, Tokai-mura, Japan

This is a summary of the presentations and discussions of the Accelerator System working group at the 68th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams.

Slides FRA2I3 [0.262 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I3

About •

Received ※ 22 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 15 December 2023

Cite •

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