Author/Authors :
Nobukawa، نويسنده , , Kumiko Kawabata and Tsuru، نويسنده , , Takeshi Go and Nobukawa، نويسنده , , Masayoshi and Tanaka، نويسنده , , Takaaki and Uchida، نويسنده , , Hiroyuki and Tsunemi، نويسنده , , Hiroshi and Hayashida، نويسنده , , Kiyoshi and Anabuki، نويسنده , , Naohisa and Nakajima، نويسنده , , Hiroshi and Nagino، نويسنده , , Ryo and Dotani، نويسنده , , Tadayasu and Ozaki، نويسنده , , Masanobu and Natsukari، نويسنده , , Chikara and Tomida، نويسنده , , Hiroshi and Kimura، نويسنده , , Masashi and Yamauchi، نويسنده , , Makoto and Mori، نويسنده , , Koji and Hatsukade، نويسنده , , Isamu and Nishioka، نويسنده , , Yusuke and Kohmura، نويسنده , , Takayoshi and Hiraga، نويسنده , , Junko Sato and Murakami، نويسنده , , Hiroshi، نويسنده ,
Abstract :
We are developing the Soft X-ray Imager (SXI), a charge-coupled device (CCD) camera system to be deployed onboard the ASTRO-H satellite. Using an engineering model system in which design specifications were the same as those of the flight model, we measured charge transfer inefficiency (CTI) and the effects of charge trailing. The CCD was irradiated with monochromatic X-rays produced by a radio isotope (55Fe) and X-ray generator using alpha particles from 241Am. We used four targets for the X-ray generator: (C2F4)n, SiO2, Ti, and Ge. Since CTI degrades energy resolution, we adopted the charge-injection technique to the SXI. With this technique, injected charges fill traps, and subsequent signal charges are transferred with less loss of charge. However, the charge-injection technique can cause positional variations in gain on the CCD chip. Thus, we constructed a method for correcting CTI. We also evaluated the charge trailing effect and tested a method for correcting its effects. After applying these corrections to charge injection, variations in gain improved from 0.5% to 0.1% over the CCD chip, and the energy resolution (FWHM) improved from ~ 220 eV to ~ 180 eV at 5.9 keV.
