• J. Vollaire, A.F. Fassó, J.C. Liu, X.S. Mao, A.A. Prinz, S.H. Rokni, M. Santana-Leitner
  SLAC, Menlo Park, California

The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostic for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental station and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses beam loss assumption, the design limits and the simulations performed using the Monte-Carlo code FLUKA for the design of the shielding necessary to attenuate secondary radiations (including muons) induced by the bremsstrahlung photons. Other Radiation Safety Systems associated to the containment of the FEL beam and an overview of the Personnel Protection system is provided for completeness.