CERN Accelerating science

Article
Title	Design of a Precision Positioning System for the Undulators of the Linac Coherent Light Source
Author(s)	Trakhtenberg, Emil ; Collins, Jeffrey T ; Den Hartog, Patric ; White, Marion
Affiliation	(ANL, Argonne, Illinois)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.4099
Subject category	Accelerators and Storage Rings
Abstract	A precision positioning system has been designed for the Linac Coherent Light Source (LCLS) and a prototype system is being fabricated. The LCLS will use a beam based alignment technique to precisely align all of the segments of the 130-m long undulator line. The requirement for overlap between the electron beam and the x-ray beam, in order to develop and maintain lasing, demands that each of the quadrupoles be aligned within a tolerance of ± 2 μm and that the undulator axis be positioned within ± 10 μm vertically and horizontally. Five cam movers, each with an eccentricity of 1.5 mm, will allow adjustment of a cradle supporting the undulator, its vacuum chamber, a quadrupole, and a beam position monitor. An additional motion transverse to the beam axis allows removal of individual undulators from the beam path. Positioning feedback will be provided by a wire position monitor system and a hydrostatic leveling system.