Thermal analyses for initial operations of the Soft X-Ray Spectrometer (SXS) onboard ASTRO-H

Hirofumi Noda, Kazuhisa Mitsuda, Atsushi Okamoto, Yuichiro Ezoe, Kumi Ishikawa, Ryuichi Fujimoto, Noriko Yamasaki, Yoh Takei, Takaya Ohashi, Yoshitaka Ishisaki, Ikuyuki Mitsuishi, Seiji Yoshida, Michael DiPirro, Peter Shirron

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

13 Citations (Scopus)

Abstract

The Soft X-ray Spectrometer (SXS) onboard ASTRO-H (Hitomi) achieved a high energy resolution of ∼ 4.9 eV at 6 keV with an X-ray microcalorimeter array kept at 50 mK in the orbit. The cooling system utilizes liquid helium, and a porous plug phase separator is utilized to confine it. Therefore, it is required to keep the helium temperature always lower than the λ point of 2.17 K in the orbit. To clarify the maximum allowable helium temperature at the launch also considering the uncertainties of the initial operation in the orbit, we constructed a thermal mathematical model of the SXS dewar which properly implements the helium mass flow rate through the porous plug, and carried out time-series thermal simulations. Based on the results, the maximum allowable helium temperature at the launch was set at 1.7 K. We also conducted a transient thermal calculation using the actual temperatures at the launch as initial conditions. As a result, the helium mass flow rate when the helium temperature was in equilibrium is estimated to be 34-42 μg/s, and the life time of the helium mode is predicted to be ∼ 3.9-4.7 years. The present paper reports model structures, simulation results, and the comparisons with temperatures measured in the orbit.

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
PublisherSPIE
ISBN (Electronic)9781510601895
DOIs
Publication statusPublished - 2016 Jan 1
EventSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray - Edinburgh, United Kingdom
Duration: 2016 Jun 262016 Jul 1

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9905
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
CountryUnited Kingdom
CityEdinburgh
Period16/6/2616/7/1

Keywords

  • ASTRO-H (Hitomi)
  • Cryogenics
  • The Soft X-ray Spectrometer (SXS)
  • Thermal mathematical model
  • Thermal simulation
  • X-ray microcalorimeter

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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