Development of focal plane x-ray detector aboard a microsatellite for monitoring supermassive blackholes
Development of focal plane x-ray detector aboard a microsatellite for monitoring supermassive blackholes
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开发用于监测超大质量黑洞的微型卫星焦平面X射线探测器
DOI：
10.1117/12.2311990
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Hironori Sahara
中科院分区：
文献类型：
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作者：
Hiroshi Nakajima;Satomi Onishi;Jun-ichi Iwagaki;Junko S. Hiraga;John P. Doty;Hirokazu Ikeda;Yuichiro Ezoe;Naoki Isobe;Hironori Sahara
我们描述了用于观测宇宙X射线发射的微小卫星上焦平面探测器的研制。结合焦距约40 mm的X射线光学元件，X射线CCD相机能够根据事件的脉冲高度分布对事件进行分类，从而实现了低本底和稳定的本底。该飞行任务将密切监测一个特定的双星黑洞，以调查由于其可能的双星运动而产生的周期性时间变异性。焦平面探测器采用P沟道背照型CCD。它是Hitomi卫星上的CCD相机使用的传感器的微型版本，但在能量分辨率和防止可见光透过率方面进行了升级。我们已经建立了一套冷却和驱动该装置的设备。研究了暗电流与器件温度的关系。我们看到成像区域和帧存储区域之间暗电流的大小有明显的差异，这可能是由于像素大小的不同造成的。结果表明，当温度低于或等于-80°C时，可以获得足够低的暗电流。不同器件表面铝层上的针孔数量有很大差异。我们确定了一个减少针孔数量的过程。为了实现一个完整的仪器，我们开发了通信板和紧凑的模拟板。
We describe the development of the focal plane detector onboard a micro-satellite aimed for observing cosmic Xray emission. Combined with an X-ray optics with focal length of approximately 40 mm, an X-ray CCD camera realizes low and stable background thanks to its capability of event classification by pulse height distribution of a event. The mission will intensively monitor a specific binary black hole to investigate periodic time variability owing to its possible binary motion. The focal plane detector adopts P-channel back-illumination type CCD. It is a miniature version of the sensors utilized in the CCD camera aboard Hitomi satellite but is upgraded in terms of the energy resolution and the prevention of visible light transmittance. We have built up an equipment for cooling and driving the device. Dark current as a function of device temperature is investigated. We see clear difference of the amount of the dark current between the imaging area and frame store area, which is probably due to the difference of the pixel size. The result indicates sufficiently low dark current can be achieved with temperature lower or equal to -80 °C. Number of pinholes in a surface aluminium layer is significantly different between devices. We identified a process with which we decrease the number of pinholes. To realize a whole instrument, we develop communication board and compact analog board.