25–29 Sept 2015
International Conference Center (also named as <a href="http://www.jdnyhotel.com/index.php" target="_blank">“Nanyang Hotel”</a>)
PRC timezone

Modeling the Response Function for Soft X-ray Imager onbord ASTRO-H Satellite

26 Sept 2015, 19:56
1m
Multi-function Hall (International Conference Center (Nanyang Hotel))

Multi-function Hall

International Conference Center (Nanyang Hotel)

Speaker

Shota Inoue (Osaka university)

Description

The ASTRO-H satellite is the 6th Japanese X-ray astronomical observatory to be launched in FY2015. The satellite carries four kinds of detectors, and one of them is an X-ray charge-coupled device (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 $31\,{\rm mm}\times31\,{\rm mm}$, arrayed in mosaic, covering the whole field of view of $38’\times38’$, the widest ever flown in orbit. The CCDs are a P-channel back-illuminated (BI) type with a depletion layer thickness of $200\,$um. We operate the CCDs in a photon counting mode in which the position and energy of each photon in the energy range of $0.4-12\,$keV are measured. To evaluate the X-ray spectra obtained with the SXI, the accurate calibration of its response function is essential. For this purpose, we performed calibration experiments in Osaka University, Kyoto University, and the synchrotron facility at KEK, each with different X-ray sources with various X-ray energies. We fit the obtained spectra with 6 components; primary peak, secondary peak, constant tail, Si escape and Si fluorescence, and then model their energy dependence using physics based or empirical formulae. Since this is the first time for the P-channel BI type CCDs on the X-ray satellite, we need special care on the constant tail component which is originated in partial charge collection. We notice that we need to assume a trapping layer at the incident surface of the CCD and implemented in the response model. We also note that we have to consider detailed spectral features in the incident X-ray spectrum, even with conventional $^{55}$Fe sources, to obtain accurate response functions.

Primary author

Shota Inoue (Osaka university)

Co-authors

Hiroshi Nakajima (Osaka University) Hiroshi Tsunemi (Osaka University) Hiroyuki Uchida (Kyoto University) Kiyoshi Hayashida (Osaka University) Koji Mori (Miyazaki University) Koki Tamasawa (Tokyo University of Science) Kumiko Nobukawa (Kyoto University) Masayoshi Nobukawa (Kyoto University) Naohisa Anabuki (Osaka University) Ryo Nagino (Osaka University) Shoma Tanno (Tokyo University of Science) Shuhei Katada (Osaka University) Shutaro Ueda (ISAS/JAXA) Takaaki Tanaka (Kyoto University) Takahiro Konno (Tokyo University of Science) Takayoshi Kohmura (Tokyo University of Science) Takeshi Tsuru (Kyoto University) Yuma Yoshino (Tokyo University of Science)

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