TY - GEN
T1 - Thermal analyses for initial operations of the Soft X-Ray Spectrometer (SXS) onboard ASTRO-H
AU - Noda, Hirofumi
AU - Mitsuda, Kazuhisa
AU - Okamoto, Atsushi
AU - Ezoe, Yuichiro
AU - Ishikawa, Kumi
AU - Fujimoto, Ryuichi
AU - Yamasaki, Noriko
AU - Takei, Yoh
AU - Ohashi, Takaya
AU - Ishisaki, Yoshitaka
AU - Mitsuishi, Ikuyuki
AU - Yoshida, Seiji
AU - DiPirro, Michael
AU - Shirron, Peter
N1 - Funding Information:
The authors are deeply grateful to all members of the ASTRO-H team and cryogenic group at the Niihama division of Sumitomo Heavy Industries, Ltd. for their supports. HN was supported by the Grant-in-Aid for Young Scientists (B) (26800095) from the Japan Society for the Promotion of Science (JSPS), and the Special Postdoctoral Researchers Program in RIKEN.
Publisher Copyright:
© 2016 SPIE.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016
Y1 - 2016
N2 - 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.
AB - 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.
KW - ASTRO-H (Hitomi)
KW - Cryogenics
KW - The Soft X-ray Spectrometer (SXS)
KW - Thermal mathematical model
KW - Thermal simulation
KW - X-ray microcalorimeter
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U2 - 10.1117/12.2231356
DO - 10.1117/12.2231356
M3 - Conference contribution
AN - SCOPUS:85003678489
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Space Telescopes and Instrumentation 2016
A2 - Bautz, Marshall
A2 - Takahashi, Tadayuki
A2 - den Herder, Jan-Willem A.
PB - SPIE
T2 - Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
Y2 - 26 June 2016 through 1 July 2016
ER -