Title: Signatures of misalignment in x-ray cavities of cavity-based x-ray free-electron lasers

Abstract

Cavity-based x-ray free-electron lasers (CBXFEL) will allow the use of optical cavity feedback to support generation of fully coherent x-rays of high brilliance and stability by electrons in undulators. CBXFEL optical cavities comprise Bragg-reflecting flat crystal mirrors, which ensure x-rays circulation on a closed orbit, and x-ray refractive lenses, which stabilize the orbit and refocus the x-rays back on the electrons in the undulator. Depending on the cavity design, there are tens of degrees of freedom of the optical elements, which can never be perfectly aligned. Here, we study signatures of misalignment of the optical components and of the undulator source with the purposes of understanding the effects of misalignment on x-ray beam dynamics, understanding misalignment tolerances, and developing cavity alignment procedures. Betatron oscillations of the x-ray beam trajectory (both symmetric and asymmetric) are one of the characteristic signatures of cavity misalignment. The oscillation period is in the general case a noninteger number of round-trip passes of x-rays in the cavity. This period (unlike the amplitude and offset of the oscillations) is independent of the type of misalignment and is defined by cavity parameters. The studies are performed on an example of a four-crystal rectangular cavity using analytical and numericalmore » wave optics as well as ray-tracing techniques. Both confocal and generic stable cavity types are studied.« less

Authors:

Qi, Peng ;

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• Search DOE PAGES for ORCID "0000-0001-6612-9550"
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Shvyd’ko, Yuri

• Search DOE PAGES for author "Shvyd’ko, Yuri"
• Search DOE PAGES for ORCID "0000-0002-9558-1500"
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Publication Date:

2022-05-05

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1866647

Alternate Identifier(s):

OSTI ID: 1960726

Grant/Contract Number:  

AC02- 06CH11357; AC02-06CH11357

Resource Type:

Published Article

Journal Name:

Physical Review Accelerators and Beams

Additional Journal Information:

Journal Name: Physical Review Accelerators and Beams Journal Volume: 25 Journal Issue: 5; Journal ID: ISSN 2469-9888

Publisher:

American Physical Society

Country of Publication:

United States

Language:

English

Subject:

47 OTHER INSTRUMENTATION; Synchrotron radiation & free-electron lasers