超快光学诊断系统CCD相机探测性能评价与测试

Measurement and Evaluation of CCD Camera's Detecting Performance in Ultrafast Optic Diagnostic Systems

为解决超快光学诊断系统(如条纹相机,像增强器选通型分幅相机等)中记录CCD相机的性能评价问题,分析得出记录CCD相机对探测下限和动态范围更加看重,提出了适用于超快光学诊断系统记录CCD相机光学性能评价的两个原则:1)将有物理意义的像素群作为性能比较的单元,这样能去除CCD相机像素大小和像素数目带来的差异;2)宜使用最小可探测光强和光学动态范围作为CCD相机探测性能的衡量参数,这样能去除CCD相机数字化灰度、输出噪声起伏等带来的差异。在上述原则基础上,建立了不同种类CCD相机光学探测性能对比测试示例系统,对某型科学级CCD相机和某型EMCCD相机进行了对比测试。测试结果表明,EMCCD相机比科学级CCD相机具有更低的最小可探测光强和更宽的动态范围。上述CCD相机探测性能比较方法已经在Z箍缩超快光学诊断系统建立过程中得到成功应用。

To establish a method of comparing record CCD camera’s performance in ultrafast optic diagnostic systems （e.g. streak cameras, frame cameras based on gated micro channel plate intensifier, etc.）, the CCD camera’s main performance parameters were compared and discussed. It is the analyzing result that CCD camera’s lower detectable limit and dynamic range both are the most important aspects of these systems. Two rules that can ensure one comparing different CCD cameras’ performance without installing them onto a virtual system were introduced. First, the pixel group associated with the minimal resolvable element of the system should be treated as a unit so that the CCD cameras with different pixel number and different pixel size can be compared fairly. Second, the minimal detectable optic power and the optic dynamic range are both chosen to be the appropriate parameters for evaluating the performance among CCD cameras with different digital levels and output fluctuations. A demonstration system for evaluating different CCD cameras offline was constituted where a scientific grade CCD camera and an EMCCD camera were tested. Compared with the scientific grade CCD camera, the EMCCD camera’s minimal detectable optic power is lower and its dynamic range is wider. The method was successfully applied in the constitution of the ultrafast optic diagnostic system for Z pinch.