In-flight verification of the calibration and performance of the ASTRO-H (Hitomi) Soft X-Ray Spectrometer

Maurice A. Leutenegger, Marc Audard, Kevin R. Boyce, Gregory V. Brown, Meng P. Chiao, Megan E. Eckart, Ryuichi Fujimoto, Akihiro Furuzawa, Matteo Guainazzi, Daniel Haas, Jan Willem Den Herder, Takayuki Hayashi, Ryo Iizuka, Manabu Ishida, Yoshitaka Ishisaki, Richard L. Kelley, Naomichi Kikuchi, Caroline A. Kilbourne, Shu Koyama, Sho KurashimaYoshitomo Maeda, Maxim Markevitch, Dan McCammon, Kazuhisa Mitsuda, Hideyuki Mori, Nozomi Nakaniwa, Takashi Okajima, Stéphane Paltani, Robert Petre, F. Scott Porter, Kosuke Sato, Toshiki Sato, Makoto Sawada, Peter J. Serlemitsos, Hiromi Seta, Gary Sneiderman, Yang Soong, Satoshi Sugita, Andrew E. Szymkowiak, Yoh Takei, Makoto Tashiro, Yuzuru Tawara, Masahiro Tsujimoto, Cor P. De Vries, Tomomi Watanabe, Shinya Yamada, Noriko Yamasaki

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

12 Citations (Scopus)


The Soft X-ray Spectrometer (SXS) onboard the Astro-H (Hitomi) orbiting x-ray observatory featured an array of 36 silicon thermistor x-ray calorimeters optimized to perform high spectral resolution x-ray imaging spectroscopy of astrophysical sources in the 0.3-12 keV band. Extensive pre-flight calibration measurements are the basis for our modeling of the pulse-height-energy relation and energy resolution for each pixel and event grade, telescope collecting area, detector efficiency, and pulse arrival time. Because of the early termination of mission operations, we needed to extract the maximum information from observations performed only days into the mission when the onboard calibration sources had not yet been commissioned and the dewar was still coming into thermal equilibrium, so our technique for reconstructing the per-pixel time-dependent pulse-height-energy relation had to be modified. The gain scale was reconstructed using a combination of an absolute energy scale calibration at a single time using a fiducial from an onboard radioactive source, and calibration of a dominant time-dependent gain drift component using a dedicated calibration pixel, as well as a residual time-dependent variation using spectra from the Perseus cluster of galaxies. The energy resolution was also measured using the onboard radioactive sources. It is consistent with instrument-level measurements accounting for the modest increase in noise due to spacecraft systems interference. We use observations of two pulsars to validate our models of the telescope area and detector efficiency, and to derive a more accurate value for the thickness of the gate valve Be window, which had not been opened by the time mission operations ceased. We use observations of the Crab pulsar to refine the pixel-to-pixel timing and validate the absolute timing.

Original languageEnglish
Title of host publicationSpace Telescopes and Instrumentation 2016
Subtitle of host publicationUltraviolet to Gamma Ray
EditorsMarshall Bautz, Tadayuki Takahashi, Jan-Willem A. den Herder
ISBN (Electronic)9781510601895
Publication statusPublished - 2016
Externally publishedYes
EventSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray - Edinburgh, United Kingdom
Duration: 26-06-201601-07-2016

Publication series

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


OtherSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
Country/TerritoryUnited Kingdom

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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