IPAC2019 - List of Authors (Cousineau, S.M.)

Paper	Title	Page
MOPTS120	Commissioning of the New Experimental FODO Line at the SNS Beam Test Facility	1164
	A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, V. Tzoganis, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA Z.L. Zhang UTK, Knoxville, Tennessee, USA
	The SNS Beam Test Facility consists of a 2.5MeV proton accelerator and a beam line with various diagnostics for high intensity beam dynamics study. A FODO line consisting of 19 quadrupole magnets and a large dynamic range emittance monitor has been added recently. The new setup is design for experimental study of mechanisms of halo formation in mismatched high intensity beams. We present results of the new beam line commissioning with beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS120
About •	paper received ※ 07 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPTS009	Operating the SNS RF H⁻ Ion Source with a 10% Duty Factor	1951
	M.P. Stockli, M.E. Clemmer, S.M. Cousineau, B. Han, T.A. Justice, Y.W. Kang, S.N. Murray, T.R. Pennisi, C. Piller, R.F. Welton ORNL, Oak Ridge, Tennessee, USA I.N. Draganic, R.W. Garnett, D. Kleinjan, G. Rouleau LANL, Los Alamos, New Mexico, USA V.G. Dudnikov Muons, Inc, Illinois, USA C. Stinson ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work was performed at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 and at Los Alamos National Laboratory under contract DE-AC52-06NA25396 for the U.S. Department of Energy. The SNS (Spallation Neutron Source) (radio-frequency) RF-driven, H⁻ ion source injects ~50 mA of H⁻ beam into the SNS accelerator at 60 Hz with a 6% duty factor. It injects up to 7 A·hrs of H⁻ ions during its ~14-week service cycles, which is an unprecedented lifetime for small-emittance, high-current pulsed H⁻ ion sources. The SNS source also features unprecedented low cesium consumption and can be installed and started up in <10 h. Presently, the LANSCE (Los Alamos Neutron Science CEnter) accelerator complex in Los Alamos is fed by a filament-driven, biased converter-type H⁻ source that operates with a high plasma duty factor of 10%. It needs to be replaced every 4 weeks with a ~4 day startup phase. The measured negative beam current of 16-18 mA falls below the desired 21 mA acceptance of LANSCE’s accelerator especially since the beam contains several mA of electrons. LANSCE and SNS are exploring the possibility of using the SNS RF H⁻ source at LANSCE to increase the H⁻ beam current and the ion source lifetime while decreasing the startup time. For this purpose, the SNS H⁻ source has been tested at a 10% duty factor by operating it at 120 Hz with 840 µs plasma pulses generated with ~30 kW of 2 MHz RF power, and extracting ~25 mA around-the-clock for 28 days. This, and additional tests and other considerations are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS009
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPMP049	Sequential Excitation Scheme for Laser Stripping of Hydrogen Ion Beams	3558
	Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A. Rakhman ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. Resonant laser excitation of the electron in a hydrogen atom is essential to achieve high-efficiency laser stripping of hydrogen ion (H⁻) beam. In the laser stripping experiments recently carried out at SNS, an ultra-violet (UV) laser was used to excite the electrons in 1-GeV hydrogen atoms from the n=1 state to the n=3 state. In this talk, we propose a sequential resonant excitation scheme by using two laser beams to excite electrons in a sequence of two steps: from the n=1 state to the n=2 state and from the n=2 state to any higher state. The advantages of the sequential resonant excitation scheme include (1) lower laser power requirement due to higher transition probability in the first excitation step and (2) possibility of shifting the stripping laser wavelength from UV regime to longer wavelengths. An application of the sequential resonant excitation scheme in combination with the double-resonance optical cavity technology to the laser stripping of 1.3-GeV H⁻ beam (envisioned in the SNS proton power upgrade project) will be described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP049
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

Commissioning of the New Experimental FODO Line at the SNS Beam Test Facility

1164

A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, V. Tzoganis, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
Z.L. Zhang
UTK, Knoxville, Tennessee, USA

The SNS Beam Test Facility consists of a 2.5MeV proton accelerator and a beam line with various diagnostics for high intensity beam dynamics study. A FODO line consisting of 19 quadrupole magnets and a large dynamic range emittance monitor has been added recently. The new setup is design for experimental study of mechanisms of halo formation in mismatched high intensity beams. We present results of the new beam line commissioning with beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS120

About •

paper received ※ 07 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)

TUPTS009

Operating the SNS RF H⁻ Ion Source with a 10% Duty Factor

1951

M.P. Stockli, M.E. Clemmer, S.M. Cousineau, B. Han, T.A. Justice, Y.W. Kang, S.N. Murray, T.R. Pennisi, C. Piller, R.F. Welton
ORNL, Oak Ridge, Tennessee, USA
I.N. Draganic, R.W. Garnett, D. Kleinjan, G. Rouleau
LANL, Los Alamos, New Mexico, USA
V.G. Dudnikov
Muons, Inc, Illinois, USA
C. Stinson
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work was performed at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 and at Los Alamos National Laboratory under contract DE-AC52-06NA25396 for the U.S. Department of Energy.
The SNS (Spallation Neutron Source) (radio-frequency) RF-driven, H⁻ ion source injects ~50 mA of H⁻ beam into the SNS accelerator at 60 Hz with a 6% duty factor. It injects up to 7 A·hrs of H⁻ ions during its ~14-week service cycles, which is an unprecedented lifetime for small-emittance, high-current pulsed H⁻ ion sources. The SNS source also features unprecedented low cesium consumption and can be installed and started up in <10 h. Presently, the LANSCE (Los Alamos Neutron Science CEnter) accelerator complex in Los Alamos is fed by a filament-driven, biased converter-type H⁻ source that operates with a high plasma duty factor of 10%. It needs to be replaced every 4 weeks with a ~4 day startup phase. The measured negative beam current of 16-18 mA falls below the desired 21 mA acceptance of LANSCE’s accelerator especially since the beam contains several mA of electrons. LANSCE and SNS are exploring the possibility of using the SNS RF H⁻ source at LANSCE to increase the H⁻ beam current and the ion source lifetime while decreasing the startup time. For this purpose, the SNS H⁻ source has been tested at a 10% duty factor by operating it at 120 Hz with 840 µs plasma pulses generated with ~30 kW of 2 MHz RF power, and extracting ~25 mA around-the-clock for 28 days. This, and additional tests and other considerations are discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS009

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)

THPMP049

Sequential Excitation Scheme for Laser Stripping of Hydrogen Ion Beams

3558

Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A. Rakhman
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Resonant laser excitation of the electron in a hydrogen atom is essential to achieve high-efficiency laser stripping of hydrogen ion (H⁻) beam. In the laser stripping experiments recently carried out at SNS, an ultra-violet (UV) laser was used to excite the electrons in 1-GeV hydrogen atoms from the n=1 state to the n=3 state. In this talk, we propose a sequential resonant excitation scheme by using two laser beams to excite electrons in a sequence of two steps: from the n=1 state to the n=2 state and from the n=2 state to any higher state. The advantages of the sequential resonant excitation scheme include (1) lower laser power requirement due to higher transition probability in the first excitation step and (2) possibility of shifting the stripping laser wavelength from UV regime to longer wavelengths. An application of the sequential resonant excitation scheme in combination with the double-resonance optical cavity technology to the laser stripping of 1.3-GeV H⁻ beam (envisioned in the SNS proton power upgrade project) will be described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP049

About •

paper received ※ 14 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)