Author: Middleman, K.J.
Paper Title Page
MOPFI068 High Repetition Rate Highly Stable S-band Photocathode Gun for the CLARA Project 437
  • B.L. Militsyn, L.S. Cowie, P. Goudket, S.P. Jamison, J.W. McKenzie, K.J. Middleman, R. Valizadeh, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  • M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  Compact Linear Accelerator for Research and Applications (CLARA) is a 250 MeV electron facility which is under development at STFC ASTeC. The CLARA photo-injector is based on a RF photocathode gun operating with metal photocathodes and driven by a third harmonic of Ti: Sapphire laser (266 nm). The injector will be operated with laser pulses with an energy of up to 2 mJ, pulse durations down to 180 fs FWHM and a repetition rate of up to 400 Hz. In order to investigate performance of different photocathodes the gun is equipped with a load-lock system which would allow replacement of the photocathodes. Duration and emittance of electron bunches essentially depends on the mode of operation and vary from 0.1 ps at 20 pC to 5 ps at 200 pC and from 0.2 to 2 mm mrad respectively. Requirements for the stability of beam arrival time at the CLARA experimental area are extremely high and vary from hundreds down to tenths femtoseconds. In the presented article we analyse stability of the guns with 1.5 and 2.5 cell and the beam quality delivered by a gun with coaxial and waveguide coupler and analyse possibility of injection time stabilisation with low level RF and optical feedback system.  
MOPFI069 Preparation of the Polycrystalline Copper Photocathodes for the VELA RF Photocathode Gun 440
  • R. Valizadeh, A.N. Hannah, K.J. Middleman, B.L. Militsyn, T.C.Q. Noakes, R.N.C. Santer
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  The Electron Beam Test Facility (EBTF) is a high performance electron source under commissioning at ASTeC. The photoinjector of the source is based on a S-band photocathode RF gun operating with a copper photocathode which is driven by a third harmonic of Ti: Sapphire laser (266 nm). The photocathode used in the RF gun is an integrated part of the gun cavity which is polycrystalline copper disk, polished to 1um roughness, and is placed at the back wall of the first 0.5 cell in the gun cavity. In order to accomplish a procedure to activate surface prior installation, copper test samples with roughness of 0.1 um were prepared by different techniques. The best results have been obtained by ex-situ plasma cleaning in an oxygen atmosphere. Analyses showed that there was no carbon on the surface and the surface was composed of copper oxide. After heating the sample in-situ to 220 C for almost all the surface oxide was removed. For this surface a QE of 2 x10-5 was measured. Further heating to higher temperature did not result in any improvement either in surface composition nor a noticeable increase in QE. Prepared such a way operational photocathode is now under commissioning in the gun.  
TUPEA058 The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation 1265
  • J.A. Clarke, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, P.A. Corlett, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, L. Ma, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, R.N.C. Santer, Y.M. Saveliev, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R. Appleby, M. Serluca, G.X. Xia
    UMAN, Manchester, United Kingdom
  • R.J. Barlow, A.M. Kolano
    University of Huddersfield, Huddersfield, United Kingdom
  • R. Bartolini, I.P.S. Martin
    Diamond, Oxfordshire, United Kingdom
  • N. Bliss, R.J. Cash, G. Cox, G.P. Diakun, A. Gallagher, D.M.P. Holland, B.G. Martlew, M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • L.T. Campbell, B.W.J. MᶜNeil
    USTRAT/SUPA, Glasgow, United Kingdom
  • S. Chattopadhyay
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • D. Newton, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.  
THPWA036 Implementation and Commissioning of the New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System 3708
  • P.A. McIntosh, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, J.A. Clarke, B.D. Fell, A.R. Goulden, C. Hill, F. Jackson, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.C.Q. Noakes, Y.M. Saveliev, B.J.A. Shepherd, S.L. Smith, T.T. Thakker, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • N. Bliss, G. Cox, G.P. Diakun, A. Gleeson, L. Ma, B.G. Martlew, A.J. Moss, K. Robertson, M.D. Roper, R.J. Smith
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  The EBTF facility will provide enabling infrastructures targeted at the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications in medicine, health, security, energy and industrial processing. The facility has now been implemented at Daresbury Laboratory and the commissioning of the critical accelerator systems has been performed. The facility is now preparing for first exploitation with partnering industries that will be able to utilise the electron beam parameters available on EBTF to either demonstrate new techniques and/or processes or otherwise develop new technologies for future commercial realisation.