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Improvement of the crossed undulator design for effective circular polarization control in X-ray FELs

Abstract

The production of X-ray radiation with a high degree of circular polarization constitutes an important goal at XFEL facilities. A simple scheme to obtain circular polarization control with crossed undulators has been proposed so far. In its simplest configuration the crossed undulators consist of pair of short planar undulators in crossed position separated by an electromagnetic phase shifter. An advantage of this configuration is a fast helicity switching. A drawback is that a high degree of circular polarization (over 90 %) can only be achieved for lengths of the insertion devices significantly shorter than the gain length, i.e. at output power significantly lower than the saturation power level. The obvious and technically possible extension considered in this paper, is to use a setup with two or more crossed undulators separated by phase shifters. This cascade crossed undulator scheme is distinguished, in performance, by a fast helicity switching, a high degree of circular polarization (over 95%) and a high output power level, comparable with the saturation power level in the baseline undulator at fundamental wavelength. We present feasibility study and exemplifications for the LCLS baseline in the soft X-ray regime. (orig.)
Authors:
Geloni, Gianluca; [1]  Kocharyan, Vitali; Saldin, Evgeni [2] 
  1. European XFEL GmbH, Hamburg (Germany)
  2. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
Publication Date:
Jan 15, 2011
Product Type:
Technical Report
Report Number:
DESY-11-009
Subject:
43 PARTICLE ACCELERATORS; BEAM PRODUCTION; BEAM TRANSPORT; ELECTRON BEAMS; EMISSION SPECTRA; FEASIBILITY STUDIES; FREE ELECTRON LASERS; HELICITY; LASER RADIATION; ONDULATOR RADIATION; PHASE SHIFT; PHOTON BEAMS; POLARIZATION; POLARIZED BEAMS; SOFT X RADIATION; WIGGLER MAGNETS; X-RAY LASERS; X-RAY SPECTRA
OSTI ID:
21403495
Research Organizations:
Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Other: ISSN 0418-9833; TRN: DE11F2453
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21403495
Submitting Site:
DEN
Size:
16 pages
Announcement Date:
Mar 19, 2011

Citation Formats

Geloni, Gianluca, Kocharyan, Vitali, and Saldin, Evgeni. Improvement of the crossed undulator design for effective circular polarization control in X-ray FELs. Germany: N. p., 2011. Web.
Geloni, Gianluca, Kocharyan, Vitali, & Saldin, Evgeni. Improvement of the crossed undulator design for effective circular polarization control in X-ray FELs. Germany.
Geloni, Gianluca, Kocharyan, Vitali, and Saldin, Evgeni. 2011. "Improvement of the crossed undulator design for effective circular polarization control in X-ray FELs." Germany.
@misc{etde_21403495,
title = {Improvement of the crossed undulator design for effective circular polarization control in X-ray FELs}
author = {Geloni, Gianluca, Kocharyan, Vitali, and Saldin, Evgeni}
abstractNote = {The production of X-ray radiation with a high degree of circular polarization constitutes an important goal at XFEL facilities. A simple scheme to obtain circular polarization control with crossed undulators has been proposed so far. In its simplest configuration the crossed undulators consist of pair of short planar undulators in crossed position separated by an electromagnetic phase shifter. An advantage of this configuration is a fast helicity switching. A drawback is that a high degree of circular polarization (over 90 %) can only be achieved for lengths of the insertion devices significantly shorter than the gain length, i.e. at output power significantly lower than the saturation power level. The obvious and technically possible extension considered in this paper, is to use a setup with two or more crossed undulators separated by phase shifters. This cascade crossed undulator scheme is distinguished, in performance, by a fast helicity switching, a high degree of circular polarization (over 95%) and a high output power level, comparable with the saturation power level in the baseline undulator at fundamental wavelength. We present feasibility study and exemplifications for the LCLS baseline in the soft X-ray regime. (orig.)}
place = {Germany}
year = {2011}
month = {Jan}
}