In-Orbit Performance of the Hard X-Ray Detector on Board Suzaku

Kokubun, M.; Makishima, Kazuo; Takahashi, Tadayuki; Murakami, T.; Tashiro, M.; Fukazawa, Yasushi; Kamae, T.; Madejski, G. M.; Nakazawa, K.; Yamaoka, K.; Terada, Y.; Yonetoku, Daisuke; Watanabe, Shin; Tamagawa, Toru; Mizuno, T.; Kubota, Aya; Isobe, Naoki; Takahashi, Isao; Sato, G.; Takahashi, H.; Hong, Su Jin; Kawaharada, Madoka; Kawano, Naoki; Mitani, Takefumi; Murashima, M.; Suzuki, Mitsuaki; Abe, K.; Miyawaki, R.; Ohno, M.; Tanaka, Takaaki; Yanagida, Takayuki; Itoh, Takeshi; Ohnuki, Kousuke; Tamura, Kenichi; Endo, Y.; Hirakuri, S.; Hiruta, T.; Kitaguchi, Takao; Kishishita, Tetsuichi; Sugita, S.; Takahashi, Takuya; Takeda, Shin’ichiro; Enoto, T.; Hirasawa, Ayumi; Katsuta, J.; Matsumura, Satoshi; Onda, K.; Sato, Mitsuhiro; Ushio, Masayoshi; Ishikawa, Shin-­nosuke; Murase, Koichi; Odaka, Hirokazu; Suzuki, Masanobu; Yaji, Yuichi; Yamada, S.; Yamasaki, Tomonori; Yuasa, Takayuki

doi:10.1093/pasj/59.sp1.s53

Cited by 296 publications

(105 citation statements)

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“…The selection of sample AGNs is the same as Fukazawa et al (2011a); they are detected by HXD-PIN (Kokubun et al 2007;Takahashi et al 2007) above 15 keV. This ensures a high signal-to-noise ratio around the Fe-K lines.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Fe–K LINE TIME VARIABILITY AND Ni ABUNDANCE OF DISTANT REFLECTORS IN SEYFERT GALAXIES

Fukazawa

Furui

Hayashi

et al. 2016

ApJ

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We have performed systematic studies of narrow Fe-K line (6.4 keV) flux variability and Ni-K line intensity for Seyfert galaxies, using Suzaku and XMM-Newton archival data. Significant Fe-K line variability of several tens ofpercentwas detected for a pair of observations separated by 1000-2000 days (Cen A, IC 4329 A, NGC 3516, and NGC 4151) and 158 days (NGC 3516). These timescales are larger by a factor of 10-100 than the inner radius of the torus, consistent with the view that X-ray reflection by a torus is a main origin for a narrow Fe-K line. TheNi-K line was detected with a>2σ level for theCircinus galaxy, Cen A, MRK 3, NGC 4388, and NGC 4151. A mean and variance of the Ni-Kα to Fe-Kα line intensity ratios are 0.066 and 0.026, respectively. Comparing this with the Monte-Carlo simulation of reflection, theNi to Fe abundance ratio is 1.9±0.8 solar. We discuss the results and thepossibility of Ni abundance enhancement.

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Section: Observations and Data Reductionmentioning

confidence: 99%

Fe–K LINE TIME VARIABILITY AND Ni ABUNDANCE OF DISTANT REFLECTORS IN SEYFERT GALAXIES

Fukazawa

Furui

Hayashi

et al. 2016

ApJ

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“…While during the passage through the SAA the instruments are usually not operative, so that the prompt background can be neglected, proton induced radioactive decays give rise to delayed events (from seconds to hours) that increase the background level when the spacecraft is out of the SAA region [11]. As already mentioned, the aim of the present work is the study of the prompt background but, on the basis of the Suzaku/PIN experience [11] and given the nearly equatorial orbit (less and shorter SAA passages [12]), we expect an increase of the background rate less than 50%. The near-Earth environment is populated by the following sources of prompt background: (i) the diffuse photonic background; (ii) the primary protons (Galactic Cosmic Rays, GCR); (iii) the albedo charged particles; (iv) Xray and γ-ray albedo; (v) albedo neutrons.…”

Section: The Space Radiation Environment In Low Earth Orbitmentioning

confidence: 99%

The low Earth orbit radiation environment and its impact on the prompt background of hard x-ray focusing telescopes

Fioretti

Bulgarelli

Malaguti

et al. 2012

High Energy, Optical, and Infrared Detectors for Astronomy V

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The background minimization is a science-driven necessity in order to reach deep sensitivity levels in the hard X-ray band, one of the key scientific requirements for hard X-ray telescopes (e.g. NuSTAR, ASTRO-H). It requires a careful modeling of the radiation environment and new concepts of shielding systems. We exploit the Bologna Geant4 Multi-Mission Simulator (BoGEMMS) features to evaluate the impact of the Low Earth Orbit (LEO) radiation environment on the prompt background level for a hybrid Si/CdTe soft and hard X-ray detection assembly and a combined active and passive shielding system. For each class of particles, the spectral distribution of the background flux is simulated, exploring the effect of different materials (plastic vs inorganic active scintillator) and configurations (passive absorbers enclosing or surrounded by the active shielding) on the background count rate. While protons are efficiently removed by the active shielding, an external passive shielding causes the albedo electrons and positrons to be the primary source of background. Albedo neutrons are instead weakly interactive with the active shielding, and they cause an intense background level below 10 keV via elastic scattering. The best shielding configuration in terms of background and active shielding count rates is given by an inorganic scintillator placed inside the passive layers, with the addition of passive material to absorb the intense fluorescence lines of the active shielding and avoid escape peaks on the CdTe detector.

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“…The imagers are made from double-sided Si strip detectors (DSSD) 4,5 and a newly developed CdTe double-sided strip detector (CdTe-DSD), 6 coupled to specifically developed lownoise analog application-specific integrated circuit (ASIC). 7 The HXI also adopts the low background technology verified by the hard x-ray detector (HXD) 8,9 onboard the "Suzaku" satellite, in particular the well-shaped-thick active-shield to realize low background. 10 The HXT employs a newly developed multilayer super mirror optics.…”

Section: Introductionmentioning

confidence: 99%

Hard x-ray imager onboard Hitomi (ASTRO-H)

Nakazawa

Sato

Kokubun

et al. 2018

J. Astron. Telesc. Instrum. Syst.

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Abstract. The hard x-ray imaging spectroscopy system of "Hitomi" x-ray observatory is composed of two sets of hard x-ray imagers (HXI) coupled with hard x-ray telescopes (HXT). With a 12-m focal length, the system provides fine (1 0 :7 half-power diameter) imaging spectroscopy covering about 5 to 80 keV. The HXI sensor consists of a camera, which is composed of four layers of Si and one layer of CdTe semiconductor imagers, and an active shield composed of nine Bi 4 Ge 3 O 12 scintillators to provide low background. The two HXIs started observation on March 8 and 14, 2016 and were operational until 26 March. Using a Crab observation, 5 to 80 keV energy coverage and good detection efficiency were confirmed. The detector background level of 1 to 3 × 10 −4 counts s −1 keV −1 cm −2 (in detector geometrical area) at 5 to 80 keV was achieved, by cutting the high-background time-intervals, adopting sophisticated energy-dependent imager layer selection, and baffling of the cosmic x-ray background and active-shielding. This level is among the lowest of detectors working in this energy band. By comparing the effective area and the background, it was shown that the HXI had a sensitivity that is same to that of NuSTAR for point sources and 3 to 4 times better for largely extended diffuse sources. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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In-Orbit Performance of the Hard X-Ray Detector on Board Suzaku

Cited by 296 publications

References 20 publications

Fe–K LINE TIME VARIABILITY AND Ni ABUNDANCE OF DISTANT REFLECTORS IN SEYFERT GALAXIES

Fe–K LINE TIME VARIABILITY AND Ni ABUNDANCE OF DISTANT REFLECTORS IN SEYFERT GALAXIES

The low Earth orbit radiation environment and its impact on the prompt background of hard x-ray focusing telescopes

Hard x-ray imager onboard Hitomi (ASTRO-H)

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