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Investigation of the polarization state of dual APPLE-II undulators

DOI: 10.1107/S1600577515021645 DOI Help
PMID: 26698061 PMID Help

Authors: Matthew Hand (Diamond Light Source) , Hongchang Wang (Diamond Light Source) , Sarnjeet Dhesi (Diamond Light Source) , Kawal Sawhney (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Synchrotron Radiation , VOL 23 , PAGES 176 - 181

State: Published (Approved)
Published: January 2016
Diamond Proposal Number(s): 5028

Open Access Open Access

Abstract: The use of an APPLE II undulator is extremely important for providing a high-brilliance X-ray beam with the capability to switch between various photon beam polarization states. A high-precision soft X-ray polarimeter has been used to systematically investigate the polarization characteristics of the two helical APPLE II undulators installed on beamline I06 at Diamond Light Source. A simple data acquisition and processing procedure has been developed to determine the Stokes polarization parameters for light polarized at arbitrary linear angles emitted from a single undulator, and for circularly polarized light emitted from both undulators in conjunction with a single-period undulator phasing unit. The purity of linear polarization is found to deteriorate as the polarization angle moves away from the horizontal and vertical modes. Importantly, a negative correlation between the degree of circular polarization and the photon flux has been found when the phasing unit is used.

Journal Keywords: Multilayers; polarization; undulators

Subject Areas: Physics, Technique Development

Instruments: I06-Nanoscience

Investigation of the polarization state of dual APPLE-II.pdf