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Title: Control of linear accelerator noise in the Los Alamos free-electron laser (FEL)

The Los Alamos FEL requires tight control of the amplitudes and phases of the fields in two linear accelerator tanks to obtain stable lasing. The accelerator control loops must establish constant, stable, repeatable amplitudes and phases of the rf fields and must have excellent bandwidth to control high-frequency noise components. A model of the feedback loops has been developed that agrees well with measurements and allows easy substitution of components and circuits, thus reducing breadboarding requirements. The model permits both frequency and time-domain analysis. This paper describes the accelerator control scheme and our model and discusses the control of noise in feedback loops, showing how low-frequency-noise components (errors) can be corrected, but high-frequency-noise components (errors) are actually amplified by the feedback circuit. Measurements of noise in both open- and closed-loop modes are shown and comparison is made with results from the model calculations.
Publication Date:
OSTI Identifier:
Report Number(s):
LA-UR-86-1587; CONF-860629-4
ON: DE86011259
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: Linear accelerator conference, Stanford, CA, USA, 2 Jun 1986; Other Information: Portions of this document are illegible in microfiche products
Research Org:
Los Alamos National Lab., NM (USA)
Country of Publication:
United States
43 PARTICLE ACCELERATORS; 42 ENGINEERING; FREE ELECTRON LASERS; NOISE; CONTROL SYSTEMS; FEEDBACK; GAIN; MATHEMATICAL MODELS; AMPLIFICATION; LASERS 430303* -- Particle Accelerators-- Experimental Facilities & Equipment; 420300 -- Engineering-- Lasers-- (-1989)