High resolution electron beam measurements on the ALPHA-X laser–plasma wakefield accelerator

Gregor H. Welsh, Mark Wiggins, Riju Issac, Enrico Brunetti, Grace Manahan, Mohammad Islam, Silvia Cipiccia, Constantin Aniculaesei, Bernhard Ersfeld, Dino Jaroszynski

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The Advanced Laser–Plasma High-Energy Accelerators towards X-rays
(ALPHA-X) programme at the University of Strathclyde is developing laser–
plasma accelerators for the production of ultra-short high quality electron bunches. Focussing such LWFA bunches into an undulator, for example, requires particular attention to be paid to the emittance, electron bunch duration and energy spread. On the ALPHA-X wakefield accelerator beam line, a high intensity ultra-short pulse from a 30 TW Ti:Sapphire laser is focussed into a helium gas jet to produce femtosecond duration electron bunches in the range of 90–220 MeV. Measurements of the electron energy spectrum, obtained using a high resolution magnetic dipole spectrometer, show electron bunch r.m.s. energy spreads down to 0.5%. A pepper-pot mask is used to obtain transverse emittance measurements of a 128±3 MeV mono-energetic electron beam. An average normalized emittance of εrms,x,y = 2.2±0.7, 2.3±0.6 π-mm-mrad is measured, which is comparable to that of a conventional radio-frequency accelerator. The best measured emittance of εrms,x, = 1.1±0.1 π-mm-mrad corresponds to the resolution limit of the detection system. 3D particle-in-cell simulations of the ALPHA-X accelerator partially replicate the generation of low emittance, low energy spread bunches with charge less than 4 pC and gas flow simulations indicate both long density ramps and shock formation in the gas jet nozzle.
LanguageEnglish
Pages393-399
Number of pages7
JournalJournal of Plasma Physics
Volume78
Issue numberspecial issue 04
Early online date27 Feb 2012
DOIs
Publication statusPublished - 2012

Fingerprint

plasma accelerators
laser plasmas
emittance
accelerators
electron beams
high resolution
x rays
gas jets
energy
electrons
jet nozzles
peppers
ramps
magnetic dipoles
gas flow
radio frequencies
sapphire
energy spectra
masks
simulation

Keywords

  • high resolution
  • electron beam measurements
  • alpha-x
  • laser–plasma wakefield accelerator
  • ultra-short high quality electron bunches

Cite this

Welsh, Gregor H. ; Wiggins, Mark ; Issac, Riju ; Brunetti, Enrico ; Manahan, Grace ; Islam, Mohammad ; Cipiccia, Silvia ; Aniculaesei, Constantin ; Ersfeld, Bernhard ; Jaroszynski, Dino. / High resolution electron beam measurements on the ALPHA-X laser–plasma wakefield accelerator. In: Journal of Plasma Physics. 2012 ; Vol. 78, No. special issue 04. pp. 393-399.
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abstract = "The Advanced Laser–Plasma High-Energy Accelerators towards X-rays(ALPHA-X) programme at the University of Strathclyde is developing laser–plasma accelerators for the production of ultra-short high quality electron bunches. Focussing such LWFA bunches into an undulator, for example, requires particular attention to be paid to the emittance, electron bunch duration and energy spread. On the ALPHA-X wakefield accelerator beam line, a high intensity ultra-short pulse from a 30 TW Ti:Sapphire laser is focussed into a helium gas jet to produce femtosecond duration electron bunches in the range of 90–220 MeV. Measurements of the electron energy spectrum, obtained using a high resolution magnetic dipole spectrometer, show electron bunch r.m.s. energy spreads down to 0.5{\%}. A pepper-pot mask is used to obtain transverse emittance measurements of a 128±3 MeV mono-energetic electron beam. An average normalized emittance of εrms,x,y = 2.2±0.7, 2.3±0.6 π-mm-mrad is measured, which is comparable to that of a conventional radio-frequency accelerator. The best measured emittance of εrms,x, = 1.1±0.1 π-mm-mrad corresponds to the resolution limit of the detection system. 3D particle-in-cell simulations of the ALPHA-X accelerator partially replicate the generation of low emittance, low energy spread bunches with charge less than 4 pC and gas flow simulations indicate both long density ramps and shock formation in the gas jet nozzle.",
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High resolution electron beam measurements on the ALPHA-X laser–plasma wakefield accelerator. / Welsh, Gregor H.; Wiggins, Mark; Issac, Riju; Brunetti, Enrico; Manahan, Grace; Islam, Mohammad; Cipiccia, Silvia; Aniculaesei, Constantin; Ersfeld, Bernhard; Jaroszynski, Dino.

In: Journal of Plasma Physics, Vol. 78, No. special issue 04, 2012, p. 393-399.

Research output: Contribution to journalArticle

TY - JOUR

T1 - High resolution electron beam measurements on the ALPHA-X laser–plasma wakefield accelerator

AU - Welsh, Gregor H.

AU - Wiggins, Mark

AU - Issac, Riju

AU - Brunetti, Enrico

AU - Manahan, Grace

AU - Islam, Mohammad

AU - Cipiccia, Silvia

AU - Aniculaesei, Constantin

AU - Ersfeld, Bernhard

AU - Jaroszynski, Dino

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AB - The Advanced Laser–Plasma High-Energy Accelerators towards X-rays(ALPHA-X) programme at the University of Strathclyde is developing laser–plasma accelerators for the production of ultra-short high quality electron bunches. Focussing such LWFA bunches into an undulator, for example, requires particular attention to be paid to the emittance, electron bunch duration and energy spread. On the ALPHA-X wakefield accelerator beam line, a high intensity ultra-short pulse from a 30 TW Ti:Sapphire laser is focussed into a helium gas jet to produce femtosecond duration electron bunches in the range of 90–220 MeV. Measurements of the electron energy spectrum, obtained using a high resolution magnetic dipole spectrometer, show electron bunch r.m.s. energy spreads down to 0.5%. A pepper-pot mask is used to obtain transverse emittance measurements of a 128±3 MeV mono-energetic electron beam. An average normalized emittance of εrms,x,y = 2.2±0.7, 2.3±0.6 π-mm-mrad is measured, which is comparable to that of a conventional radio-frequency accelerator. The best measured emittance of εrms,x, = 1.1±0.1 π-mm-mrad corresponds to the resolution limit of the detection system. 3D particle-in-cell simulations of the ALPHA-X accelerator partially replicate the generation of low emittance, low energy spread bunches with charge less than 4 pC and gas flow simulations indicate both long density ramps and shock formation in the gas jet nozzle.

KW - high resolution

KW - electron beam measurements

KW - alpha-x

KW - laser–plasma wakefield accelerator

KW - ultra-short high quality electron bunches

U2 - 10.1017/S0022377812000220

DO - 10.1017/S0022377812000220

M3 - Article

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SP - 393

EP - 399

JO - Journal of Plasma Physics

T2 - Journal of Plasma Physics

JF - Journal of Plasma Physics

SN - 0022-3778

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