Welsh, Gregor H. and Wiggins, Mark and Issac, Riju and Brunetti, Enrico and Manahan, Grace and Islam, Mohammad and Cipiccia, Silvia and Aniculaesei, Constantin and Ersfeld, Bernhard and Jaroszynski, Dino (2012) High resolution electron beam measurements on the ALPHA-X laser-plasma wakefield accelerator. Journal of Plasma Physics, 78 (specia). pp. 393-399. ISSN 0022-3778Full text not available in this repository. (Request a copy from the Strathclyde author)
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.
|Keywords:||high resolution , electron beam measurements , alpha-x , laser–plasma wakefield accelerator, ultra-short high quality electron bunches, Physics|
|Subjects:||Science > Physics|
|Department:||Faculty of Science > Physics|
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|Depositing user:||Pure Administrator|
|Date Deposited:||01 Oct 2012 11:51|
|Last modified:||11 Jun 2013 16:28|
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