Electron beam quality measurements on the ALPHA-X Laser-plasma wakefield accelerator

G. H. Welsh, M. P. Anania, C. Aniculaesei, E. Brunetti, R. T. L. Burgess, S. Cipiccia, D. Clark, B. Ersfeld, M. R. Islam, R. C. Issac, G. G. Manahan, T. McCanny, G. Raj, A.-J. W. Reitsma, R. P. Shanks, G. Vieux, S. M. Wiggins, D. A. Jaroszynski, W. A. Gillespie, A. M. MacLeodS. B. van der Geer, M. J. de Loos

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme at the University of Strathclyde is developing laser-plasma wakefield accelerators to produce high energy, ultra-short duration electron bunches as drivers of radiation sources. Coherent emission will be produced in a free-electron laser by focussing the ultra-short electron bunches into an undulator. To achieve net gain, high peak current, low energy spread and low emittance are required. 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 80-200 MeV. Beam transport is monitored using a series of Lanex screens positioned along the beam line. Measurements of the electron energy spectrum, obtained using the ALPHA-X high resolution magnetic dipole spectrometer, are presented. The maximum central energy of the monoenergetic beam is 90 MeV and r.m.s. relative energy spreads as low as 0.8% are measured. The mean central energy is 82 + 4 MeV and mean energy spread is 1.1 + 0.4%. We also present pepper-pot measurements of the normalised transverse emittance where mono-energetic electrons are passed through an array of 52µm diameter holes in tungsten. The analysis of the pepper-pot results sets an upper limit for the normalised emittance at 5.5 ± 1p mm mrad for an 82 MeV beam. With further acceleration to 1 GeV, the relative energy spread will reduce giving beam parameters that indicate the feasibility of a compact X-ray FEL driven by a plasma-wakefield accelerator.
    Original languageEnglish
    Title of host publicationIPAC' 10
    Subtitle of host publicationProceedings of the 1st International Particle Accelerator Conference
    Place of PublicationGeneva
    Number of pages3
    ISBN (Print)9789290833529
    Publication statusPublished - 2010
    Event1st International Particle Accelerator Conference - Kyoto International Conference Center, Kyoto, Japan
    Duration: 23 May 201028 May 2010


    Conference1st International Particle Accelerator Conference
    Abbreviated titleIPAC'10
    Internet address


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