As a new generation of image sensors, CCDs are widely used in the field of astronomical observation.CCDs'dark current significantly affect the image quality of astronomical observations. Dark current is sensitive to the temperature. In order to improve the image quality, we need to refrigerate CCD. The general methods of CCD cooling are semiconductor cooling and liquid nitrogen cooling.The CCD butting project of Yunnan Observatory is cooled by liquid nitrogen method, cooling equipment is Dewar. After CCD cooling, dark current will become very small. However, after cooling dark current fluctuations caused by temperature fluctuations is between a few percent of itself to dozens of percent. In order to further improve the image quality of astronomical observations, we not only require for cooling CCD, but also have a high-precision temperature control , which is particularly important in high-precision astronomical observations, especially low-luminosity high-precision observations of the dark star. By the same token, the CCD butting project of Yunnan Observatory also require high-precision temperature control system. This temperature control system is designed specifically for CCD butting target surface . This paper firstly introduces the CCD and the temperature control requirements, and then combined with CCD butting cold plate and the Dewar of the physical environment,gives preliminary design and analysis of cold plate thermal control and draws the conclusions. Secondly, this paper presents the hardware and software design of upper and lower computer of CCD butting target surface temperature control system. then finds the most suitable method for cold plate temperature control algorithm of CCD butting by debugging over and over again in the real tests. Finally, sums up the progresses of the system and gives prospects for future research.
修改评论