Lateral shift mapping metrology for X-ray telescope mirrors

Hayden J. Wisniewski, Mallory M. Whalen, Ralf K. Heilmann, Mark L. Schattenburg, Brandon D. Chalifoux

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


Currently, high-resolution X-ray telescope mirrors, such as for the Lynx X-Ray Observatory concept, are measured using a Fizeau interferometer with a cylindrical null corrector. Uncertainties in the null wavefront directly couple into the surface measurement uncertainty, including the axial figure and cone angle variation. We extend the absolute surface metrology method of lateral shift mapping for measuring X-ray telescope mirror segments. Lateral shift mapping involves laterally shifting the surface under test relative to the null to multiple positions. The null wavefront can be extracted from the difference between these shifted measurements, leaving only the surface under test. Accurately extracting quadratic terms of the surface under test requires measuring its tilt during shifting. We will show surface metrology results of optical flats measured by Fizeau-based lateral shift mapping with the required angle measured using an autocollimator and compare these results against a three-flat test. We will show how we plan to extend this method to conical X-ray telescope mirror metrology. The lateral shift mapping method reduces the uncertainty introduced by the cylindrical null, a critical step toward making high-resolution X-ray telescope mirrors.

Original languageEnglish (US)
Title of host publicationOptics for EUV, X-Ray, and Gamma-Ray Astronomy X
EditorsStephen L. O'Dell, Jessica A. Gaskin, Giovanni Pareschi
ISBN (Electronic)9781510644823
StatePublished - 2021
EventOptics for EUV, X-Ray, and Gamma-Ray Astronomy X 2021 - San Diego, United States
Duration: Aug 1 2021Aug 5 2021

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptics for EUV, X-Ray, and Gamma-Ray Astronomy X 2021
Country/TerritoryUnited States
CitySan Diego


  • Absolute metrology
  • Lynx
  • Metrology
  • X-ray mirror metrology
  • X-ray telescope

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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