Study Of Key Technologies Of Near-Infrared Sky Brightness Detection System

Infrared astronomy is an important branch of astronomy and astrophysics,whose main purpose is to study various sources of celestial bodies in the infrared band.The infrared spectrum is very wide,among which 1?5um is called near infrared,5-25um is called mid-infrared,25?1000um is called far-infrared.According to Wien's displacement law,the lower the celestial body temperature is,the larger the peak wavelength of radiation is,and it is in the infrared band.In addition,the early celestial bodies are important data for understanding the origin of the universe and studying the evolution of the universe.Due to the phenomenon of redshift in the universe,the wavelength of radiation emitted by early celestial bodies will be red-shifted to infrared wavelengths.The large number of cold objects existing in the universe plays an important role in expanding human vision and enriching the theory of astronomy.Therefore,infrared astronomical technology is of great significance for the development of astronomy.The 1um?5um infrared band is an important band in infrared astronomy research.Infrared sky brightness monitoring is an important part of ground-based infrared astronomical observations.The intensity of the light radiation of the sky background largely limits the performances of the telescopes,such as the sky survey depth,exposure time of astronomical imaging systems and so on.The infrared background must first be measured before choosing a good infrared observation site,and only the site with a low infrared background is suitable for infrared observations.For the measurement of infrared sky brightness,obtaining the characteristics of the near-infrared observation conditions of the area,especially the near-infrared background radiation average intensity and variation parameters,will provide reference for future design of infrared telescopes and other observation equipment.At the same time,development of infrared sky brightness measurement system is of crucial importance to the design of infrared cameras and the design of infrared surveying scientific projects.In addition,the infrared sky brightness background value can provide sky brightness background data for the design of other related infrared instruments.The lack of good infrared astronomical observatory sites and equipment in China for a long time has restricted the development of related disciplines of infrared observation in China.At present,there are no relevant infrared sky brightness background measurement data for all major astronomical observatory sites in China,including various scientific research stations in Antarctica,the Tibet Ngari Observatory that is under construction,and the Daocheng Observatory in Sichuan.Research on the infrared sky brightness background measurement system is in urgent need of breakthrough.In order to solve this problem,this paper selects the best single-point infrared detector in different near-infrared bands,combines the design of relevant modules,and conducts research on the key technologies of the sky brightness background measuring instrument.The main topics include optical design,structural design,electrical controls,detectors and optical cooling,high-gain electronics readouts and control software design.Infrared sky brightness background measuring instrument based on InGaAs detector and InSb detector are used for open-air testing to verify the overall performance of the equipment.At the same time,corresponding infrared sky brightness background data of Hefei,Anhui and Ngari,Tibet are obtained and basic data analysis is conducted.The innovations of this thesis are as follows:(1)Based on InGaAs detectors,the key technologies of the near infrared sky brightness monitor for the J,H,and Ks bands were studied.The corresponding optics,structures,electronics systems,and underlying firmware programs were designed and they were performed at the Ngari Observatory in Tibet for a long period of time(more than half a year).In the observation experiment,the near infrared sky brightness background data of the J,K,and K bands in Ngari were obtained for the first time.(2)A software control system with automatic observation function was designed,and a long-term observation experiment is carried out in Ngari observatory in Tibet,the software runs steadily.(3)Infrared sky brightness monitor for the 2.5?5um band was designed.Developed the vacuum system,ultra-low temperature refrigeration,continuous control of variable wavelength,and weak signal detection technology.Calibration of instrument performance parameters was completed.