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Article
Title	RF Design for the Linac Coherent Light Source (LCLS) Injector
Author(s)	Dowell, D H ; Bentson, Lynn D ; Boyce, Richard F ; Hodgson, J A ; Li, Zenghai ; Limborg-Deprey, C ; Xiao, Liling ; Yu, Nancy
Affiliation	(SLAC, Menlo Park, California SLAC/LCLS, Menlo Park, California)
Publication	2004
In:	26th International Free Electron Laser Conference and 11th FEL User Workshop 2004, Trieste, Italy, 29 Aug - 3 Sep 2004, pp.e-proc. TUPOS56
Subject category	Accelerators and Storage Rings
Abstract	The Linac Coherent Light Source (LCLS) will be the world’s first free electron laser, and the successful operation of this very short-wavelength FEL will require excellent beam quality from its electron source. Therefore a critical component is the RF photocathode injector. This paper describes the design issues of the LCLS RF gun and accelerator structures. The injector consists of a 1.6 cell s-band gun followed by two 3-meter SLAC sections. The gun and the first RF section will have dual RF feeds both to eliminate transverse RF kicks and to reduce the pulsed heating of the coupling ports. In addition, the input coupler cavity of the first accelerator section will be specially shaped to greatly reduce the RF quadrupole fields. The design for the accelerator section is now complete, and the RF design of the gun’s dual coupler and the full cell shape is in progress. These and other aspects of the gun and structure designs will be discussed.