Angular resolution measurements at SPring-8 of a hard X-ray optic for the new hard X-ray mission

D. Spiga, L. Raimondi, A. Furuzawa, S. Basso, R. Binda, G. Borghi, V. Cotroneo, G. Grisoni, H. Kunieda, F. Marioni, H. Matsumoto, H. Mori, T. Miyazawa, B. Negri, A. Orlandi, G. Pareschi, B. Salmaso, G. Tagliaferri, K. Uesugi, G. ValsecchiD. Vernani

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

10 Citations (Scopus)


The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (< 0.25 deg) grazing angles to enhance the reflectivity of reflective coatings. On the other hand, to obtain large collecting area, large mirror diameters (< 350 mm) are necessary. This implies that mirrors with focal lengths ≥10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with onground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aimed at characterizing the Point Spread Function (PSF) of a multilayer-coated Wolter-I mirror shell manufactured by Nickel electroforming. The mirror shell is a demonstrator for the NHXM hard X-ray imaging telescope (0.3 - 80 keV), with a predicted HEW (Half Energy Width) close to 20 arcsec. We show some reconstructed PSFs at monochromatic X-ray energies of 15 to 63 keV, and compare them with the PSFs computed from post-campaign metrology data, self-consistently treating profile and roughness data by means of a method based on the Fresnel diffraction theory. The modeling matches the measured PSFs accurately.

Original languageEnglish
Title of host publicationOptics for EUV, X-Ray, and Gamma-Ray Astronomy V
Publication statusPublished - 2011
Externally publishedYes
EventOptics for EUV, X-Ray, and Gamma-Ray Astronomy V - San Diego, CA, United States
Duration: 23-08-201125-08-2011

Publication series

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


OtherOptics for EUV, X-Ray, and Gamma-Ray Astronomy V
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

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


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