Measurement and optimization of the VISA undulator

Author

Rakowsky, G. ; Aspenleiter, J. ; Solomon, L. ; Car, R. ; Ruland, R. ; Lidia, S.

Author_Institution

Brookhaven Nat. Lab., Upton, NY, USA

Volume

4

fYear

1999

fDate

1999

Firstpage

2698

Abstract

The Visible-Infrared SASE Amplifier (VISA) undulator is an in-vacuum, 4-meter long, 1.8 cm period, pure-permanent magnet device, with a novel, strong focusing, permanent magnet FODO array included within the fixed, 6 mm undulator gap. The undulator magnet is constructed of 99-cm long segments, joined into a continuous structure. To attain maximum SASE gain requires establishing overlap of electron and photon beams to within 50 microns rms. This imposes challenging tolerances on mechanical fabrication and magnetic field quality, and necessitates use of laser straightness interferometry for calibration and alignment of the magnetic axes of the undulator segments. This paper describes the computerized magnet sorting, pulsed-wire magnetic measurements, trajectory shimming and magnetic axis calibration performed to meet this goal

Keywords

calibration; permanent magnets; superradiance; wigglers; VISA undulator; Visible-Infrared SASE Amplifier undulator; computerized magnet sorting; laser straightness interferometry; magnetic axis calibration; magnetic field quality; mechanical fabrication; permanent magnet FODO array; pulsed-wire magnetic measurements; pure-permanent magnet device; trajectory shimming; undulator gap; undulator magnet; undulator segments; Calibration; Electron beams; Interferometry; Laser beams; Magnetic devices; Magnetic field measurement; Optical device fabrication; Permanent magnets; Sorting; Undulators;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 1999. Proceedings of the 1999

Conference_Location

New York, NY

Print_ISBN

0-7803-5573-3

Type

conf

DOI

10.1109/PAC.1999.792908

Filename

792908