This report describes the ionizing radiation protection and safety issues in the design of the Next Linear Collider Test Accelerator (NLCTA), a high-gradient, 1-GeV, Xband linac at SLAC.
INTRODUCTIONThe Next Linear Collider Test Accelerator (NLCTA) is a high-gradient, X-band linac at SLAC designed to validate 2.6-cm microwave linear accelerator technology for a future high-energy linear collider (the Next Linear Collider).' This report describes the ionizing radiation protection and safety issues in the design of the NLCTA, including power limits, shielding, and safety systems.* The NLCTA beam line ( Fig. 1) consists of an injector, chicane, linac, and spectrometer. The injector contains a 3-A, 1 50-kV, pulsed thermionic-cathode gun and two 0.9-m-long X-band accelerator ~ections.~ The sections are energized by a single 50-MW klystron, and boost the beam energy by up to 90 MeV (50 MV/m). The gun pulse has 0.125-ps duration. The repetition rate is