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暗电流在科学级电荷耦合器件(CCD)长时间曝光测试实验中是主要的噪声之一。实验测试了暗电流信号平均计数随曝光时间的变化关系,并经过计算得出-10℃和-20℃下暗电流分别为2.43ADU/(s.pixel)和0.4854ADU/(s.pixel),同时测试了暗电流随CCD制冷温度的变化特性,结果显示暗电流随温度类似指数函数形式变化。由于CCD机械快门的时间响应特性对科学级光学CCD的短时曝光计数的影响比较大,实验测试了CCD平均计数和曝光时间的关系,得出实验所用的TEK 512pixel×512pixel DB CCD的机械快门在18ms时能够完全打开。
Dark current is one of the major noises in a scientific-class charge-coupled device (CCD) long-time exposure test. The dark current signal average count with the exposure time was experimentally tested, and the dark current was calculated to be 2.43ADU / (s.pixel) and 0.4854ADU / (s.pixel) at -10 ℃ and -20 ℃, respectively. Simultaneously, the characteristics of dark current with the cooling temperature of CCD were tested. The results show that the dark current changes with the exponential function of temperature. Because of the time-response characteristics of CCD mechanical shutter on the short-term exposure count of the scientific optical CCD, the relationship between the CCD average count and the exposure time is experimentally tested, and the mechanical shutter of the TEK 512 pixel × 512 pixel DB CCD 18ms when fully open.