NAPAC2019 - List of Authors (Aleksandrov, A.V.)

Paper	Title	Page
TUYBB2	Manipulating H⁻ Beams with Lasers	309
	A. Rakhman, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, Y. Liu, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. In recent years lasers have been playing a vital role in many H− beam measurements and experiments. This talk will review current state of development of various applications using lasers for manipulating H− ion beams in accelerators. A wide range of applications will be reviewed such as beam diagnostics, laser-assisted charge-exchange injection, generation of arbitrary H⁰ pulse patterns and others. An overview of ongoing developments and prospects for other laser H− beam interactions will also be given.
	Slides TUYBB2 [16.483 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB2
About •	paper received ※ 28 August 2019 paper accepted ※ 12 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYBB5	A Crab-Crossing Scheme for Laser-Ion Beam Applications	639
	A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, Y. Liu, A. Rakhman, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Lasers have recently been used in many applications to H⁻ beams, including laser charge exchange, laser wire scanners, and laser temporal pulse patterning. The H⁻ beam in these applications has wide variation ofμpulse length width dependence on focusing of the RF cavities, energy spread of the beam, and space charge forces. Achieving the required laser pulse length for complete overlap with the H⁻ can be challenging in some scenarios when available laser power constrained. The scheme proposed here utilizes a crab-crossing concept between the laser and the ion beam to achieve overlap of a short laser pulse with an arbitrarily long H⁻ beam pulse. An experiment to test the hypothesis in the context of H⁻ charge exchange is described.
	Slides WEYBB5 [5.201 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB5
About •	paper received ※ 30 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLH10	Efficiency Estimation for Sequential Excitation Laser Stripping of H⁻ Beam	827
	T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A. Rakhman ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UTBattelle, LLC, under contract DEAC0500OR22725 for the U.S. Department of Energy. A new laser stripping scheme for charge exchange injection of H⁻ beam is considered. The sequential scheme for the planned demonstration experiment includes two step excitation that requires much smaller laser power compared to the traditional 1-step excitation. The new scheme can be applied to a wider range of H⁻ beam energies and provides more flexibility on the choice of laser frequency. In this paper we discuss the two-step excitation method and estimate laser stripping parameters and stripping efficiency for the SNS accelerator and its future H⁻ energy upgrade to 1.3 GeV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH10
About •	paper received ※ 22 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THZBA4	Characterization and Modeling of High-Intensity Evolution in the SNS Beam Test Facility	954
	K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau ORNL, Oak Ridge, Tennessee, USA Z.L. Zhang ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Partial support by NSF Accelerator Science grant 1535312 Modern high-power accelerators are charged with delivering reliable beam with low losses. Resolving the complex dynamics arising from space charge and nonlinear forces requires detailed models of the accelerator and particle-in-cell simulation. There has historically been discrepancy between simulated and measured beam distributions, particularly at the low-density halo level. The Beam Test Facility (BTF) at the Spallation Neutron Source is outfitted to study beam evolution in a high-power linear accelerator MEBT. This includes capability for high-dimensional measurements of the post-RFQ beam distribution, including interplane correlations that may be the key to accurate simulation. Beam is transported through a 4.6 m FODO channel (9.5 cells) to a second distribution measurement stage. Plans for validating simulations against BTF measurements of beam evolution in the FODO channel are discussed.
	Slides THZBA4 [8.316 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA4
About •	paper received ※ 27 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THZBB5	Present Status and Upgrades of the SNS Ion Beam Bunch Shape Monitors	968
	V. Tzoganis, A.V. Aleksandrov, R.W. Dickson ORNL, Oak Ridge, Tennessee, USA
	Six interceptive Feschenko-style longitudinal bunch profile monitors have been deployed in the normal conducting part of the SNS linac and HEBT. They have been operational for more than 10 years and although their performance has been satisfactory, reliability and parts obsolescence must be addressed. The upgrade plan focuses in mainly two areas, electronics architecture modernization and improvement of measurement resolution. In the first phase that is presented here the objective is to improve the control and readout electronics taking advantage of more recent technology. This will primarily address the obsolescence issues with older components, the frequent RF power failures, the non-trivial maintenance and troubleshooting and will lead to a simpler and more reliable system. This contribution describes in detail the implemented upgrades and presents the first experimental data.
	Slides THZBB5 [4.926 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB5
About •	paper received ※ 29 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Manipulating H⁻ Beams with Lasers

309

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

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
In recent years lasers have been playing a vital role in many H− beam measurements and experiments. This talk will review current state of development of various applications using lasers for manipulating H− ion beams in accelerators. A wide range of applications will be reviewed such as beam diagnostics, laser-assisted charge-exchange injection, generation of arbitrary H⁰ pulse patterns and others. An overview of ongoing developments and prospects for other laser H− beam interactions will also be given.

Slides TUYBB2 [16.483 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUYBB2

About •

paper received ※ 28 August 2019 paper accepted ※ 12 September 2019 issue date ※ 08 October 2019

Export •

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

WEYBB5

A Crab-Crossing Scheme for Laser-Ion Beam Applications

639

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

Lasers have recently been used in many applications to H⁻ beams, including laser charge exchange, laser wire scanners, and laser temporal pulse patterning. The H⁻ beam in these applications has wide variation ofμpulse length width dependence on focusing of the RF cavities, energy spread of the beam, and space charge forces. Achieving the required laser pulse length for complete overlap with the H⁻ can be challenging in some scenarios when available laser power constrained. The scheme proposed here utilizes a crab-crossing concept between the laser and the ion beam to achieve overlap of a short laser pulse with an arbitrarily long H⁻ beam pulse. An experiment to test the hypothesis in the context of H⁻ charge exchange is described.

Slides WEYBB5 [5.201 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB5

About •

paper received ※ 30 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLH10

Efficiency Estimation for Sequential Excitation Laser Stripping of H⁻ Beam

827

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

Funding: ORNL is managed by UTBattelle, LLC, under contract DEAC0500OR22725 for the U.S. Department of Energy.
A new laser stripping scheme for charge exchange injection of H⁻ beam is considered. The sequential scheme for the planned demonstration experiment includes two step excitation that requires much smaller laser power compared to the traditional 1-step excitation. The new scheme can be applied to a wider range of H⁻ beam energies and provides more flexibility on the choice of laser frequency. In this paper we discuss the two-step excitation method and estimate laser stripping parameters and stripping efficiency for the SNS accelerator and its future H⁻ energy upgrade to 1.3 GeV.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH10

About •

paper received ※ 22 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019

Export •

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

THZBA4

Characterization and Modeling of High-Intensity Evolution in the SNS Beam Test Facility

954

K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau
ORNL, Oak Ridge, Tennessee, USA
Z.L. Zhang
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Partial support by NSF Accelerator Science grant 1535312
Modern high-power accelerators are charged with delivering reliable beam with low losses. Resolving the complex dynamics arising from space charge and nonlinear forces requires detailed models of the accelerator and particle-in-cell simulation. There has historically been discrepancy between simulated and measured beam distributions, particularly at the low-density halo level. The Beam Test Facility (BTF) at the Spallation Neutron Source is outfitted to study beam evolution in a high-power linear accelerator MEBT. This includes capability for high-dimensional measurements of the post-RFQ beam distribution, including interplane correlations that may be the key to accurate simulation. Beam is transported through a 4.6 m FODO channel (9.5 cells) to a second distribution measurement stage. Plans for validating simulations against BTF measurements of beam evolution in the FODO channel are discussed.

Slides THZBA4 [8.316 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA4

About •

paper received ※ 27 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019

Export •

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

THZBB5

Present Status and Upgrades of the SNS Ion Beam Bunch Shape Monitors

968

V. Tzoganis, A.V. Aleksandrov, R.W. Dickson
ORNL, Oak Ridge, Tennessee, USA

Six interceptive Feschenko-style longitudinal bunch profile monitors have been deployed in the normal conducting part of the SNS linac and HEBT. They have been operational for more than 10 years and although their performance has been satisfactory, reliability and parts obsolescence must be addressed. The upgrade plan focuses in mainly two areas, electronics architecture modernization and improvement of measurement resolution. In the first phase that is presented here the objective is to improve the control and readout electronics taking advantage of more recent technology. This will primarily address the obsolescence issues with older components, the frequent RF power failures, the non-trivial maintenance and troubleshooting and will lead to a simpler and more reliable system. This contribution describes in detail the implemented upgrades and presents the first experimental data.

Slides THZBB5 [4.926 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB5

About •

paper received ※ 29 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019

Export •

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