Use of a charge-injection technique to improve performance of the Soft X-ray Imager aboard ASTRO-H
Use of a charge-injection technique to improve performance of the Soft X-ray Imager aboard ASTRO-H
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使用电荷注入技术提高 ASTRO-H 上软 X 射线成像仪的性能
DOI：
10.1016/j.nima.2014.05.091
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Kumiko K. Nobukawa et al.
中科院分区：
文献类型：
--
作者：
Matsumura, Hideaki; Tsuru, Takeshi Go; Tanaka, Takaaki; Nakashima, Shinya; Ryu, Syukyo G.; Takeda, Ayaki; Arai, Yasuo; Miyoshi, Toshinobu;Kumiko K. Nobukawa et al.
我们正在开发软X射线成像仪（SXI），这是一种将部署在ASTRO-H卫星上的电荷耦合器件（CCD）相机系统。使用一个工程模型系统，其中的设计规格是相同的飞行模型，我们测量的电荷转移效率（CTI）和电荷拖尾的影响。用放射性同位素（55 Fe）产生的单色X射线和使用来自241 Am的α粒子的X射线发生器照射CCD。我们使用了四个目标的X射线发生器：（C2 F4）n，SiO2，Ti和Ge。由于CTI降低了能量分辨率，我们采用了电荷注入技术的SXI。利用这种技术，注入的电荷填充陷阱，并且随后的信号电荷以较少的电荷损失转移。然而，电荷注入技术会导致CCD芯片上的增益的位置变化。因此，我们构建了一种校正CTI的方法。我们还评估了电荷拖尾效应，并测试了校正其影响的方法。在将这些校正应用于电荷注入之后，CCD芯片的增益变化从0.5%改善到0.1%，并且能量分辨率（FWHM）在5.9 keV下从~ 220 eV改善到~ 180 eV。
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 (55 Fe) and X-ray generator using alpha particles from 241 Am. We used four targets for the X-ray generator:(C 2 F 4) n, SiO 2, 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.