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McKenzie, J. W.

Paper Title Page
MOPC066 Optimisation of a SRF High Average Current SRF Gun 220
 
  • C. D. Beard, J. W. McKenzie, B. L. Militsyn, B. D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
 
  An approximately 100 mA and 10 MeV continuous wave electron injector is required to deliver high brightness electron bunches for the spontaneous and VUV radiation sources. One of possible solutions might be a Superconductive RF (SRF) gun. Optimisation of the first half cell of the gun has been carried out to maximise the acceleration whilst providing additional focussing through shaping of the cathode region to meet the design specification. In this paper, the cavity design and specification are presented together with some initial optimisations.  
MOPC073 Design of an Upgrade to the ALICE Photocathode Electron Gun 235
 
  • B. L. Militsyn, B. D. Fell, L. B. Jones, J. W. McKenzie, K. J. Middleman
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • I. Burrows, R. J. Cash
    STFC/DL, Daresbury, Warrington, Cheshire
  • S. N. Kosolobov, H. E. Scheibler, A. S. Terekhov
    ISP, Novosibirsk
 
  The design of an upgrade to the GaAs photocathode electron gun of the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory is presented. This proposed upgrade includes a reduction of the photocathode diameter from 32 to 10 mm and the installation of a dedicated photocathode preparation system with side loading of the photocathodes. The preparation system forms a united vacuum system with the gun but is separated by a gate valve. This allows for significant improvements to the vacuum conditions in the gun and a reduction of pollution from caesium vapour which improves gun stability under high voltage. This preparation facility will reduce the time taken for photocathode changeover from weeks to hours. The facility should provide photocathodes with higher quantum efficiency due to a more controllable preparation procedure and allows experiments to be performed with photocathodes activated to different levels of electron affinity.  
MOPC074 3D Simulations of a Non-axisymmetric High Average Current DC Photocathode Electron Gun 238
 
  • J. W. McKenzie, B. L. Militsyn
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
 
  At high average currents, GaAs photocathode based electron guns are limited by the short operational lifetime of the photocathodes. One method to improve the cathode lifetime is to situate the photocathode off-axis to reduce the flow of ions back-bombarding the emitting surface. The results of 3D electrostatic and beam dynamic simulations are presented to demonstrate the feasibility of this scheme and the resultant beam quality achievable.