Search Publications
The quiescent intracluster medium in the core of the Perseus cluster
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +213 more
Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the clust…
Temporal Gain Correction for X-ray Calorimeter Spectrometers
Tsujimoto, M.; Ishisaki, Y.; Yamada, S. +14 more
Calorimetric X-ray detectors are very sensitive to their environment. The boundary conditions can have a profound effect on the gain including heat sink temperature, the local radiation temperature, bias, and the temperature of the readout electronics. Any variation in the boundary conditions can cause temporal variations in the gain of the detect…
The Si/CdTe semiconductor camera of the ASTRO-H Hard X-ray Imager (HXI)
Kokubun, Motohide; Makishima, Kazuo; Nakazawa, Kazuhiro +27 more
The Hard X-ray Imager (HXI) is one of the instruments onboard the ASTRO-H mission [1-4] to be launched in early 2016. The HXI is the focal plane detector of the hard X-ray reflecting telescope that covers an energy range from 5 to 80 keV. It will execute observations of astronomical objects with a sensitivity for point sources as faint as 1/100,00…
Operating modes and cooling capabilities of the 3-stage ADR developed for the Soft-X-ray Spectrometer instrument on Astro-H
Kelley, Richard L.; Porter, Frederick S.; DiPirro, Michael J. +8 more
A 3-stage adiabatic demagnetization refrigerator (ADR) (Shirron et al., 2012) is used on the Soft X-ray Spectrometer instrument (Mitsuda et al., 2010) on Astro-H (Takahashi et al., 2010) [3] to cool a 6 × 6 array of X-ray microcalorimeters to 50 mK. The ADR is supported by a cryogenic system (Fujimoto et al., 2010) consisting of a superfluid heliu…
Flight model performance test results of a helium dewar for the soft X-ray spectrometer onboard ASTRO-H
Mitsuda, Kazuhisa; Fujimoto, Ryuichi; Yoshida, Seiji +10 more
ASTRO-H is a Japanese X-ray astronomy satellite, scheduled to be launched in fiscal year 2015. The mission includes a soft X-ray spectrometer instrument (SXS), which contains an X-ray micro calorimeter operating at 50 mK by using an adiabatic demagnetization refrigerator (ADR). The heat sink of the ADR is superfluid liquid helium below 1.3 K. The …
Thermodynamic performance of the 3-stage ADR for the Astro-H Soft-X-ray Spectrometer instrument
Kelley, Richard L.; Porter, Frederick S.; DiPirro, Michael J. +6 more
The Soft X-ray Spectrometer (SXS) instrument (Mitsuda et al., 2010) [1] on Astro-H (Takahashi et al., 2010) [2] will use a 3-stage ADR (Shirron et al., 2012) to cool the microcalorimeter array to 50 mK. In the primary operating mode, two stages of the ADR cool the detectors using superfluid helium at ⩽1.20 K as the heat sink (Fujimoto et al., 2010…
Examining the angular resolution of the ASTRO-H's soft x-ray telescopes
Maeda, Yoshitomo; Ishida, Manabu; Okajima, Takashi +12 more
The international x-ray observatory ASTRO-H was renamed "Hitomi" after launch. It covers a wide energy range from a few hundred eV to 600 keV. It is equipped with two soft x-ray telescopes (SXTs: SXT-I and SXT-S) for imaging the soft x-ray sky up to ∼12 keV, which focus an image onto the respective focal-plane detectors: CCD camera (SXI) and a cal…
Study of the polarimetric performance of a Si/CdTe semiconductor Compton camera for the Hitomi satellite
Fukazawa, Yasushi; Ohno, Masanori; Tajima, Hiroyasu +18 more
Gamma-ray polarization offers a unique probe into the geometry of the γ-ray emission process in celestial objects. The Soft Gamma-ray Detector (SGD) onboard the X-ray observatory Hitomi is a Si/CdTe Compton camera and is expected to be an excellent polarimeter, as well as a highly sensitive spectrometer due to its good angular coverage and resolut…
Atomic scattering factor of the ASTRO-H (Hitomi) SXT reflector around the gold's L edges
Maeda, Yoshitomo; Ishida, Manabu; Okajima, Takashi +14 more
Flight model measurements of the porous plug and film flow suppression system for the ASTRO-H Soft X-ray Spectrometer dewar
Ezoe, Yuichiro; Ishikawa, Kumi; Ohashi, Takaya +9 more
Flight model measurements of a porous plug phase separator and a film flow suppression system for the ASTRO-H Soft X-ray Spectrometer dewar are described. ASTRO-H is the sixth Japanese astronomy satellite and will be launched in 2016. It carries the Soft X-ray Spectrometer consisting of an X-ray optic and an X-ray microcalorimeter system operated …