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Time assignment system and its performance aboard the Hitomi satellite
Dotani, Tadayasu; Kokubun, Motohide; Takahashi, Tadayuki +24 more
Fast timing capability in x-ray observation of astrophysical objects is one of the key properties for the ASTRO-H (Hitomi) mission. Absolute timing accuracies of 350 or 35 µs are required to achieve nominal scientific goals or to study fast variabilities of specific sources. The satellite carries a GPS receiver to obtain accurate time inform…
Design, implementation, and performance of the Astro-H soft x-ray spectrometer aperture assembly and blocking filters
Eckart, Megan E.; Kilbourne, Caroline A.; Leutenegger, Maurice A. +21 more
The calorimeter array of the JAXA Astro-H (renamed Hitomi) soft x-ray spectrometer (SXS) was designed to provide unprecedented spectral resolution of spatially extended cosmic x-ray sources and of all cosmic x-ray sources in the Fe-K band around 6 keV. The properties that made the SXS array a powerful x-ray spectrometer also made it sensitive to p…
Porous plug phase separator and superfluid film flow suppression system for the soft x-ray spectrometer onboard Hitomi
Sato, Kosuke; Yamaguchi, Hiroya; Ezoe, Yuichiro +16 more
When using superfluid helium in low-gravity environments, porous plug phase separators are commonly used to vent boil-off gas while confining the bulk liquid to the tank. Invariably, there is a flow of superfluid film from the perimeter of the porous plug down the vent line. For the soft x-ray spectrometer onboard ASTRO-H (Hitomi), its approximate…
On-ground calibration of the Hitomi Hard X-ray Telescopes
Maeda, Yoshitomo; Ishida, Manabu; Kunieda, Hideyo +46 more
We present x-ray characteristics of the Hard X-ray Telescopes (HXTs) on board the Hitomi (ASTRO-H) satellite. Measurements were conducted at the SPring-8 BL20B2 beamline and the ISAS/JAXA 27-m beamline. The angular resolution defined by a half-power diameter was 1.9‧ (HXT-1) and 2.1‧ (HXT-2) at 8 keV, 1.9‧ at 30 keV, and 1.8‧ at 50 keV. The effect…
Multilayer mirror-based soft x-ray polarimeter for astronomical observations
Marshall, Herman L.; Narendranath, Shyama; Panini, Singam S. +3 more
A simple design of a soft x-ray polarimeter using multilayer mirrors is presented. A multilayer mirror acts as a linear polarization analyzer for x-rays at incidence angles close to the Brewster angle. The instrument consists of an x-ray concentrator, a set of multilayer mirrors placed at 45 deg from the optical axis, and a detector at Nasmyth foc…
In-flight performance of the Canadian Astro-H Metrology System
Ishida, Manabu; Iizuka, Ryo; Gallo, Luigi C. +11 more
The Canadian Astro-H Metrology System (CAMS) on the Hitomi x-ray satellite is a laser alignment system that measures the lateral displacement (X/Y) of the extensible optical bench (EOB) along the optical axis of the hard x-ray telescopes (HXTs). The CAMS consists of two identical units that together can be used to discern translation and rotation …
Thermal analyses for initial operations of the soft x-ray spectrometer onboard the Hitomi satellite
Ezoe, Yuichiro; Ishikawa, Kumi; Ohashi, Takaya +11 more
The soft x-ray spectrometer (SXS) onboard the Hitomi satellite achieved a high-energy resolution of ∼4.9 eV at 6 keV with an x-ray microcalorimeter array cooled to 50 mK. The cooling system utilizes liquid helium, confined in zero gravity by means of a porous plug (PP) phase separator. For the PP to function, the helium temperature must be kept lo…
Special Section Guest Editorial: The Hitomi X-Ray Observatory, Part 2
Kelley, Richard L.; Nakazawa, Kazuhiro
This guest editorial summarizes the Special Section on the Hitomi X-Ray Observatory.
Special Section Guest Editorial: The Hitomi X-ray Observatory
Kelley, Richard L.; Nakazawa, Kazuhiro
This guest editorial introduces the Special Section on the Hitomi X-Ray Observatory, Part 1.