NAPAC2019 - Table of Session: FRXBA (Friday Parallel Session 1)

Paper	Title	Page
FRXBA1	Review of Recent Advances in Cooling Techniques
	S. Nagaitsev Fermilab, Batavia, Illinois, USA
	Beam cooling plays an important role in future electron-ion colliders. The talk will review recent advances in cooling techniques. It will especially discuss variants of electron cooling such as e.g., coherent and micro-bunched electron cooling. Other cooling technique, e.g. optical stochastic cooling will also be presented.
	Slides FRXBA1 [8.091 MB]
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FRXBA2	Diverse Beam Profile Shapings Through Nonlinear Focusing of Multipole Magnets in a Beam Transport Line
	Y. Yuri, T. Yuyama QST/Takasaki, Takasaki, Japan M. Fukuda RCNP, Osaka, Japan
	It is well-known that the transverse intensity distribution of a charged-particle beam can be made approximately uniform through the nonlinear focusing force using multipole (mainly, octupole) magnets in a beam transport line. This fact indicates that the proper use of multipole magnets enables the diverse beam profile shapings that cannot be achieved by common linear focusing, such as quadrupole magnets. We have, therefore, investigated the feasibility of the beam profile shaping (other than uniform profiles) by means of nonlinear focusing. Recently, we have experimentally demonstrated the formation of an ion beam with a hollow transverse distribution using octupole and sextupole magnets. It has been found that the hollow beam has a steep peak at the radial edge and that its cross-sectional shape varies diversely depending on the order and strength of the applied multipole magnets. In the presentation, the first experimental result of the hollow-beam formation will be reported together with the theoretical analysis of the behavior of a nonlinear-focused beam. Moreover, other unique beam profiles obtained through the nonlinear force of the multipole magnets will also be shown.
	Slides FRXBA2 [4.111 MB]
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FRXBA3	Applications and Opportunities for the Emittance Exchange Beamline	981
	G. Ha, M.E. Conde, J.G. Power ANL, Lemont, Illinois, USA M. Chung, J. Seok UNIST, Ulsan, Republic of Korea
	Funding: This work is supported by the U.S. Department of Energy, Offices of HEP and BES, under Contract No. DE-AC02-06CH11357. Emittance exchange (EEX) provides a powerful method of controlling the longitudinal phase space using the relatively simpler methods of transverse control. An EEX beamline was installed at the Argonne Wakefield Accelerator (AWA) facility in 2015. Several experiments important to the wakefield acceleration, such as a high transformer ratio from shaped bunches, have already been demonstrated. We are currently developing several applications of the EEX beamline including temporal profile shaping, THz radiation generation, time-energy correlation control, diagnostic uses of EEX etc. We will present the on-going EEX program for longitudinal phase space control taking place at the AWA facility, and discuss recently discovered new opportunities.
	Slides FRXBA3 [6.814 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA3
About •	paper received ※ 02 September 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019
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FRXBA4	Maximizing 2-D Beam Brightness Using the Round to Flat Beam Transformation in the Ultralow Charge Regime	986
SUPLM02	use link to see paper's listing under its alternate paper code
	F.W. Cropp V, P.E. Denham, J. Giner Navarro, E.T. Liu, P. Musumeci UCLA, Los Angeles, USA N. Burger, L. Phillips PBPL, Los Angeles, USA A.L. Edelen, C. Emma SLAC, Menlo Park, California, USA
	Funding: This work is supported by the United States National Science Foundation award PHY-1549132 (the Center for Bright Beams) We seek to maximize the 2-D beam brightness in an RF photoinjector operating in an ultralow charge (<1 pC) regime by implementing the FBT. Particle tracking simulations suggest that in one dimension, normalized projected emittances smaller than 5 nm can be obtained at the UCLA Pegasus facility with up to 100 fC beam charge. A tunable magnetic field is put on the cathode. Three skew quadrupoles are used to block-diagonalize the beam matrix and recover the vastly different eigenemittances as the projected emittances. Emittance measurement routines, including grid-based, pepperpot-based and quad scan routines, have been developed for on-line calculation of the 4-D beam matrix and its eigenemittances. Preliminary measurements are in agreement with simulations and indicate emittance ratios larger than 10 depending on the laser spot size on the cathode. Fine tuning the quadrupole gradients for the FBT has a significant effect on the 2-D beam brightness. We have made concrete steps toward computer minimization and machine learning optimization of the quadrupole gradients in order to remove the canonical angular momentum from the beam and achieve the target normalized projected emittances.
	Slides FRXBA4 [3.059 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA4
About •	paper received ※ 28 August 2019 paper accepted ※ 05 December 2019 issue date ※ 08 October 2019
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FRXBA5	The Role of Laser Shaping in Microbunching Instability Suppression and Seeded X-Ray Free Electron Emission	990
SUPLM09	use link to see paper's listing under its alternate paper code
	J. Tang, S. Carbajo, F.-J. Decker, Z. Huang, J. Krzywiński, R.A. Lemons, W. Liu, A.A. Lutman, G. Marcus, T.J. Maxwell, S.P. Moeller, D.F. Ratner, S. Vetter SLAC, Menlo Park, California, USA
	Microbunching instability (MBI) driven by collective effects in an accelerator is known to be detrimental for the performance of X-ray free electron lasers. At the Linac Coherent Light Source (LCLS), laser heater (LH) system was installed to suppress the microbunching instability by inducing a small amount of slice energy spread to the electron beam. The distribution of the induced energy spread greatly effects MBI suppression and can be controlled by shaping the transverse profile of the heater laser. In this paper, we present theoretical and experimental results on utilizing a Laguerre-Gaussian 01 Mode (LG01) laser at LCLS to obtain better suppression of the instability. We demonstrate experimentally that Gaussian-shaped energy distribution is induced by LG01 mode LH and final microbunching gain is better suppressed. We finally discuss the role of LH spatial shaping in soft X-ray self-seeded (SXRSS) FEL emission and demonstrate that this LH configuration is capable of generating high spectral brightness FEL pulses.
	Slides FRXBA5 [3.162 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA5
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)

Paper

Title

Page

FRXBA1

Review of Recent Advances in Cooling Techniques

S. Nagaitsev
Fermilab, Batavia, Illinois, USA

Beam cooling plays an important role in future electron-ion colliders. The talk will review recent advances in cooling techniques. It will especially discuss variants of electron cooling such as e.g., coherent and micro-bunched electron cooling. Other cooling technique, e.g. optical stochastic cooling will also be presented.

Slides FRXBA1 [8.091 MB]

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

FRXBA2

Diverse Beam Profile Shapings Through Nonlinear Focusing of Multipole Magnets in a Beam Transport Line

Y. Yuri, T. Yuyama
QST/Takasaki, Takasaki, Japan
M. Fukuda
RCNP, Osaka, Japan

It is well-known that the transverse intensity distribution of a charged-particle beam can be made approximately uniform through the nonlinear focusing force using multipole (mainly, octupole) magnets in a beam transport line. This fact indicates that the proper use of multipole magnets enables the diverse beam profile shapings that cannot be achieved by common linear focusing, such as quadrupole magnets. We have, therefore, investigated the feasibility of the beam profile shaping (other than uniform profiles) by means of nonlinear focusing. Recently, we have experimentally demonstrated the formation of an ion beam with a hollow transverse distribution using octupole and sextupole magnets. It has been found that the hollow beam has a steep peak at the radial edge and that its cross-sectional shape varies diversely depending on the order and strength of the applied multipole magnets. In the presentation, the first experimental result of the hollow-beam formation will be reported together with the theoretical analysis of the behavior of a nonlinear-focused beam. Moreover, other unique beam profiles obtained through the nonlinear force of the multipole magnets will also be shown.

Slides FRXBA2 [4.111 MB]

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FRXBA3

Applications and Opportunities for the Emittance Exchange Beamline

981

G. Ha, M.E. Conde, J.G. Power
ANL, Lemont, Illinois, USA
M. Chung, J. Seok
UNIST, Ulsan, Republic of Korea

Funding: This work is supported by the U.S. Department of Energy, Offices of HEP and BES, under Contract No. DE-AC02-06CH11357.
Emittance exchange (EEX) provides a powerful method of controlling the longitudinal phase space using the relatively simpler methods of transverse control. An EEX beamline was installed at the Argonne Wakefield Accelerator (AWA) facility in 2015. Several experiments important to the wakefield acceleration, such as a high transformer ratio from shaped bunches, have already been demonstrated. We are currently developing several applications of the EEX beamline including temporal profile shaping, THz radiation generation, time-energy correlation control, diagnostic uses of EEX etc. We will present the on-going EEX program for longitudinal phase space control taking place at the AWA facility, and discuss recently discovered new opportunities.

Slides FRXBA3 [6.814 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA3

About •

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

Export •

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

FRXBA4

Maximizing 2-D Beam Brightness Using the Round to Flat Beam Transformation in the Ultralow Charge Regime

986

SUPLM02

use link to see paper's listing under its alternate paper code

F.W. Cropp V, P.E. Denham, J. Giner Navarro, E.T. Liu, P. Musumeci
UCLA, Los Angeles, USA
N. Burger, L. Phillips
PBPL, Los Angeles, USA
A.L. Edelen, C. Emma
SLAC, Menlo Park, California, USA

Funding: This work is supported by the United States National Science Foundation award PHY-1549132 (the Center for Bright Beams)
We seek to maximize the 2-D beam brightness in an RF photoinjector operating in an ultralow charge (<1 pC) regime by implementing the FBT. Particle tracking simulations suggest that in one dimension, normalized projected emittances smaller than 5 nm can be obtained at the UCLA Pegasus facility with up to 100 fC beam charge. A tunable magnetic field is put on the cathode. Three skew quadrupoles are used to block-diagonalize the beam matrix and recover the vastly different eigenemittances as the projected emittances. Emittance measurement routines, including grid-based, pepperpot-based and quad scan routines, have been developed for on-line calculation of the 4-D beam matrix and its eigenemittances. Preliminary measurements are in agreement with simulations and indicate emittance ratios larger than 10 depending on the laser spot size on the cathode. Fine tuning the quadrupole gradients for the FBT has a significant effect on the 2-D beam brightness. We have made concrete steps toward computer minimization and machine learning optimization of the quadrupole gradients in order to remove the canonical angular momentum from the beam and achieve the target normalized projected emittances.

Slides FRXBA4 [3.059 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA4

About •

paper received ※ 28 August 2019 paper accepted ※ 05 December 2019 issue date ※ 08 October 2019

Export •

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

FRXBA5

The Role of Laser Shaping in Microbunching Instability Suppression and Seeded X-Ray Free Electron Emission

990

SUPLM09

use link to see paper's listing under its alternate paper code

J. Tang, S. Carbajo, F.-J. Decker, Z. Huang, J. Krzywiński, R.A. Lemons, W. Liu, A.A. Lutman, G. Marcus, T.J. Maxwell, S.P. Moeller, D.F. Ratner, S. Vetter
SLAC, Menlo Park, California, USA

Microbunching instability (MBI) driven by collective effects in an accelerator is known to be detrimental for the performance of X-ray free electron lasers. At the Linac Coherent Light Source (LCLS), laser heater (LH) system was installed to suppress the microbunching instability by inducing a small amount of slice energy spread to the electron beam. The distribution of the induced energy spread greatly effects MBI suppression and can be controlled by shaping the transverse profile of the heater laser. In this paper, we present theoretical and experimental results on utilizing a Laguerre-Gaussian 01 Mode (LG01) laser at LCLS to obtain better suppression of the instability. We demonstrate experimentally that Gaussian-shaped energy distribution is induced by LG01 mode LH and final microbunching gain is better suppressed. We finally discuss the role of LH spatial shaping in soft X-ray self-seeded (SXRSS) FEL emission and demonstrate that this LH configuration is capable of generating high spectral brightness FEL pulses.

Slides FRXBA5 [3.162 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA5

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)