CMOS图像传感器在太阳磁场观测中的应用研究

磁场是太阳物理的第1观测量,当前太阳磁场观测研究正迈向大视场、高时空分辨率、高偏振测量精度以及空间观测的时代.中国首颗太阳观测卫星—先进天基太阳天文台(ASO-S)也配置了具有高时空分辨率、高磁场灵敏度的全日面矢量磁像仪(FMG)载荷,针对FMG载荷的需求,讨论了大面阵、高帧频互补金属氧化物半导体(Complementary Metal Oxide Semiconductor, CMOS)图像传感器应用于太阳磁场观测的可行性.首先,基于滤光器型太阳磁像仪观测的原理,比较分析了目前CMOS图像传感器(可用的或是可选的两种快门模式)的特点,指出全局快门类型更适合FMG;其次搭建了CMOS传感器实验室测试系统,测量了CMOS图像传感器的像素增益及其分布规律;最后在怀柔太阳观测基地的全日面太阳望远镜上开展了实测验证,获得预期成果.在这些研究基础上,形成了FMG载荷探测器选型方向.

Application of CMOS Image Sensor in Solar Magnetic Field Observation

Magnetic field is one of the primary observational parameters of solar physics. Current research on solar magnetic field observation is moving towards the era of large field of view, high temporal and spatial resolution, high polarization measurement accuracy, and space observation. Full-disk vector MagnetoGraph (FMG) payload equipped with solar magnetic field observation equipment with high time resolution and high spatial resolution will be carried on the Advanced Space-based Solar Observatory (ASO-S). This paper discussed the application of large area high frame rate Complementary Metal Oxide Semiconductor (CMOS) image sensors for solar magnetic field observations in response to the needs of FMG payload feasibility. Based on the principle of filter-type solar magnetographs, we compared the characteristics of different CMOS imager sensors, and found that the CMOS imager sensor with the global shutter is the most suitable for the FMG aboard the ASO-S satellite. We also discussed a laboratory test system for the CMOS sensors, and measured the pixel gain and its distribution. Furthermore, observational test and verification experiments were implemented through the full-disk solar magnetic detection telescope at Huairou Solar Observing Station, Chinese Academy Sciences, with satisfying results. The most favorable CMOS detectors are specified based on the studies.