LCLS-II project [1] currently underway at SLAC will provide new capability as well as new capacity to the existing Linac Coherent Light Source (LCLS) Free Electron Laser. The project will add a new 4 GeV continuous-wave superconducting (SC) linear accelerator capable of generating up to 1 MHz, 1 MW of average beam power to SLAC accelerators. However, only 120 kW of beam power will be delivered to each of the two electron beam dumps after passing through each of two new variable gap undulators. The existing LCLS Linac, which is a copper based Linac located in the last kilometer of the SLAC Linac tunnel, will retain its capabilities and continue to operate at 120 Hz, up to 5 kW and up to 17 GeV.

LCLS-II will be installed in the existing SLAC linear accelerator housing, parts of which were shielded for lower LCLS average power beams. SLAC Radiation Safety System (RSS) [2] that is comprised of shielding, Access Control System and Beam Containment System (BCS) assures safe transport and operation of high power beams through the entire facility such that the design goals for radiation safety are met.
All accelerator facilities use shielding, Access Control System and interlocked radiation monitoring outside shielding as part of their standard radiation safety systems. At SLAC, BCS is a main component of RSS and is implemented as a complement to shielding. The role of BCS in LCLS-II radiation safety for the electron beams is described. Show Partial Abstract