Abstract
A wiggler is a high-power insertion device that was used in the past to produce a smooth wide-band X-ray spectrum. It is widely believed that on low-emittance synchrotrons this X-ray source loses its spatial and spectral homogeneity and therefore becomes less ideal than a scanning undulator. In this paper, we report on experimental and computational studies of an in-vacuum wiggler installed on the first fourth-generation synchrotron MAX IV. We investigate how several physical parameters affect the wiggler spectrum and propose a combination of a few of them that results in significant spectral smoothing. We also examine EXAFS spectra for possible distortions originating from the source imperfection. For this purpose, we scrutinize samples of various homogeneity. We conclude that wigglers are still an appropriate class of insertion devices, also on low-emittance synchrotrons.
Highlights
Undulators generate X-rays with the spectral distribution consisting of narrow-band harmonics
Balder is a wiggler beamline dedicated to X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) in the tender and hard X-ray energy range 2.4–45 keV (Klementiev et al, 2016)
We have studied various factors controlling the smoothness of wiggler spectra on the fourth-generation synchrotron source MAX IV
Summary
Undulators generate X-rays with the spectral distribution consisting of narrow-band harmonics. The first energy scans revealed that the amplitude of the ripples was significantly smaller and with another beating pattern compared with calculations, at that time made without magnetic field errors Those observations made us search a wide parameter space for optimal settings that deliver X-ray absorption spectra of the highest quality. Walker lists the factors that help to smooth out the spectrum: wavelength acceptance, angular acceptance, electron beam divergence, electron beam energy spread and magnetic field errors. The work should be relevant for several synchrotron facilities worldwide that consider future upgrades of their accelerator complexes towards diffraction-limited light sources
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
