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TUPPH028 The Research of FIR-FEL in CAEP electron, gun, cathode, wiggler 386
 
  • X. Yang, X. Jin, M. Li, W. Li, Z. Xu
    CAEP/IAE, Mianyang, Sichuan
  The research of FIR-FEL has been undertaken about 10 years in CAEP and first lasing at center wavelength 115·10-6 m was observed in March 2005. The facility consists of RF-gun, alpha magnet, L-band SW accelerator, beam transport line, wiggler, optical cavity and measurement system. At present, a high brightness photo cathode RF-gun is commissioning, the cathode material is Cs2Te. This injector will be used in the FIR-FEL project in the second half of this year. In this paper, the design consideration, the system layout, some experimental results are introduced.  
 
THPPH068 The Development and Application of a Photoemission Model for Cesiated Photocathode Surfaces scattering, emittance, electron, laser 744
 
  • K. Jensen, J. L. Shaw, J. E. Yater
    NRL, Washington, DC
  • D. W. Feldman, N. A. Moody
    IREAP, College Park, Maryland
  • P. G. O'Shea
    University Maryland, College Park, Maryland
  A photoemitter capable of in situ rejuvenation with a high quantum efficiency (QE) is a photocathode candidate of FELs and linear accelerators. Our program to develop a controlled porosity dispenser (CPD) photocathode* led to the development and validation of a theoretical model that accounts for low work function surfaces from submonolayer coverage of alkali (and alkali earth) metals. Here, we substantially modify our previous theoretical thermal photoemission model** by: first, considering the impact of electron-electron and electron-lattice scattering; second, by the development of an integrated absorption-transport-emission model developed to evaluate the moments of the electron emission distribution function; and third, by the inclusion of quantum effects and surface features on the emission probability***. For the experimental conditions to which we compare the resultant theory, there are no adjustable parameters. We discuss the performance of the model in the prediction of the QE of bare metals and coated surfaces, project the performance to regimes of interest to FELs, and use elements of the model to assess theoretical quantities of interest such as emittance.

* N. A. Moody, et al. (this conf.); ** K. L. Jensen, et al., (to be published in JAP99); *** K. L. Jensen, et al., APL88, 154105 (2006), ibid, 164105.