Search Publications
Modeling of proton-induced radioactivation background in hard X-ray telescopes: Geant4-based simulation and its demonstration by Hitomi's measurement in a low Earth orbit
Enoto, Teruaki; Yamaoka, Kazutaka; Fukazawa, Yasushi +47 more
Hard X-ray astronomical observatories in orbit suffer from a significant amount of background due to radioactivation induced by cosmic-ray protons and/or geomagnetically trapped protons. Within the framework of a full Monte Carlo simulation, we present modeling of in-orbit instrumental background which is dominated by radioactivation. To reduce th…
Astronomical imaging with the X-ray observatory Hitomi
Nakajima, Hiroshi; Hitomi Collaboration
We report an imaging capability of the Japan-led X-ray observatory Hitomi, formerly known as ASTRO-H. It carries four scientific instruments of Soft X-ray Imager (SXI: CCD camera), Hard X-ray Imager (HXI), Soft X-ray Spectrometer, and Soft Gamma-ray Detector, allowing us to perform a wide-band high-sensitive imaging spectroscopy. We highlight the …
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…
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…
Modeling the spectral response for the soft X-ray imager onboard the ASTRO-H satellite
Uchida, Hiroyuki; Hayashida, Kiyoshi; Nakajima, Hiroshi +20 more
The ASTRO-H satellite is the 6th Japanese X-ray astronomical observatory to be launched in early 2016. The satellite carries four kinds of detectors, and one of them is an X-ray CCD camera, the soft X-ray imager (SXI), installed on the focal plane of an X-ray telescope. The SXI contains four CCD chips, each with an imaging area of 31 mm × 31 mm , …
Development and verification of signal processing system of avalanche photo diode for the active shields onboard ASTRO-H
Yamaoka, K.; Fukazawa, Y.; Kataoka, J. +45 more
The hard X-ray Imager and Soft Gamma-ray Detector onboard ASTRO-H demonstrate high sensitivity to hard X-ray (5-80 keV) and soft gamma-rays (60-600 keV), respectively. To reduce the background, both instruments are actively shielded by large, thick Bismuth Germanate scintillators. We have developed the signal processing system of the avalanche pho…
Development of low-noise high-speed analog ASIC for X-ray CCD cameras and wide-band X-ray imaging sensors
Hayashida, Kiyoshi; Nakajima, Hiroshi; Anabuki, Naohisa +8 more
We report on the development and performance evaluation of the mixed-signal Application Specific Integrated Circuit (ASIC) developed for the signal processing of onboard X-ray CCD cameras and various types of X-ray imaging sensors in astrophysics. The quick and low-noise readout is essential for the pile-up free imaging spectroscopy with a future …