• F.E. Hannon, S.V. Benson, G.H. Biallas, D.B. Bullard, F.K. Ellingsworth, P. Evtushenko, C. Hernandez-Garcia, K. Jordan, M. Marchlik
  JLAB, Newport News, Virginia

A new 500kV DC photocathode electron gun is being developed at Jefferson Laboratory (JLab) with the aim of improving on the performance of the present FEL injector. The design benefits from the use of two inverted ceramic insulators to allow for a photocathode preparation chamber and load-lock system to be placed directly behind the gun. The electrostatic design emphasises the requirement to minimise the electric field gradients on the internal surfaces and incorporates shaped electrodes to provide some transverse focusing to the electron beam. Finally, provisions have been made to maintain ultra high vacuum conditions inside the gun chamber to prolong cathode lifetime during CW operation. This paper presents an overview of the electron gun and load-lock design.

• A. Afanasev, R.R. Ramdon
  Hampton University, Hampton, Virginia
• O.K. Baker, P. Slocum
  Yale University, Physics Department, New Haven, CT
• K.B. Beard
  Muons, Inc, Batavia
• G.H. Biallas, J.R. Boyce, M.D. Shinn
  JLAB, Newport News, Virginia
• M. Minarni
  UNRI, Riau

Cosmology provides evidence that most of the mass of the observable universe cannot be associated with any of the known Standard-Model elementary particles. Evidence of this ‘dark matter' was also obtained in the recent data from space telescopes. Axions - hypothetical particles proposed to solve a strong CP problem in Quantum Chromodynamics - are dark matter candidates. Although they carry zero electric charge, they can be produced via Primakoff mechanism, resulting in predictable effects in the laboratory. We present first results from an ongoing LIPSS experiment to search for axion-like particles with Jefferson Lab's Free Electron Laser.