Open AccessA dynamic local bump system for producing synchrotron radiation with an alternating elliptical polarization
Author(s) -
Lin K. K.,
Hsu K. T.,
Chen J. S.,
Kuo C. H.,
Chen C. S.,
Hwu K. H.,
Chen J.,
Pan K. T.,
Wang C. J.,
Chen J.R.,
Chen C. T.
Publication year - 1998
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049597013149
Subject(s) - synchrotron radiation , optics , storage ring , polarization (electrochemistry) , magnet , physics , cathode ray , beam (structure) , materials science , electron , chemistry , quantum mechanics
To facilitate high‐sensitivity soft X‐ray magnetic circular dichroism experiments, a dynamic local bump system has been developed at the SRRC storage ring. This system was devised to vary dynamically the vertical slope of the electron beam in a bending magnet, producing, in the electron orbit plane, soft X‐rays with an alternating elliptical polarization. The local bump was created by using two pairs of vertical correctors located on each side of the bending magnet. The bump strength coefficient was obtained both from calculated estimation and from measured beam‐response matrices. Control electronics for proper bump strength settings were designed to incorporate the existing orbit‐corrector function. A corresponding graphic user interface was implemented so that the bump amplitude could be easily adjusted. The performance of this system is presented. Disturbance on the stored electron beam orbit was observed while flipping the corrector polarity during EPBM (elliptical polarization from bending magnets) operation. A local feedback loop, developed to eliminate such disturbance on other beamlines, is also described.