Optical performance of the X-ray telescope for the XL-Calibur experiment

W. Kamogawa, H. Matsumoto, Q. Abarr, H. Awaki, R. Bose, D. Braun, G. De Geronimo, P. Dowkontt, T. Enoto, M. Errando, Y. Fukazawa, A. Furuzawa, T. Gadson, E. Gau, V. Guarino, S. Gunji, K. Harmon, K. Hayashida, S. Heatwole, F. ImazatoK. Ishibashi, M. Ishida, N. K. Iyer, F. Kislat, M. Kiss, T. Kitaguchi, H. Krawczynski, J. Lanzi, L. Lisalda, Y. Maeda, H. Matake, T. Mineta, T. Miyazawa, T. Mizuno, T. Okajima, M. Pearce, Z. Peterson, B. Rauch, N. Rodriguez Cavero, F. Ryde, T. A. Stana, D. Stuchlik, G. Simburgeb, S. Spooner, H. Takahashi, T. Takeda, M. Takeo, T. Tamagawa, H. Tsunemi, N. Uchida, Y. Uchida, K. Uchiyama, A. West, E. A. Wulf, Y. Yoshida

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

2 Citations (Scopus)


XL-Calibur is a balloon-borne mission for hard X-ray polarimetry. The first launch is currently scheduled from Sweden in summer 2022. Japanese collaborators provide a hard X-ray telescope to the mission. The telescope’s design is identical to the Hard X-ray Telescope (HXT, conically-approximated Wolter-I optics) on board ASTRO-H with the same focal length of 12 m and the aperture of 45 cm, which can focus X-rays up to 80 keV. The telescope is divided into three segments in the circumferential direction, and confocal 213 grazing-incidence mirrors are precisely placed in the primary and secondary sections of each segment. The surfaces of the mirrors are coated with Pt/C depth-graded multilayer to reflect hard X-rays efficiently by the Bragg reflection. To achieve the best focus, optical adjustment of all of the segments was performed at the SPring-8/BL20B2 synchrotron radiation facility during 2020. A final performance evaluation was conducted in June 2021 and the experiment yields the effective area of 175 cm2 and 73 cm2 at 30 keV and 50 keV, respectively, with its half-power diameter of the point spread function as 2.1 arcmin. The field of view, defined as the full width of the half-maximum of the vignetting curve, is 5.9 arcmin.

Original languageEnglish
Title of host publicationSpace Telescopes and Instrumentation 2022
Subtitle of host publicationUltraviolet to Gamma Ray
EditorsJan-Willem A. den Herder, Shouleh Nikzad, Kazuhiro Nakazawa
ISBN (Electronic)9781510653436
Publication statusPublished - 2022
EventSpace Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray - Montreal, United States
Duration: 17-07-202222-07-2022

Publication series

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


ConferenceSpace Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray
Country/TerritoryUnited States

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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