Research On Cryogenic Infrared Optical System For Asteroseismology

The space-based infrared system avoids the shortcomings of ground-based observations such as the absorption of the earth's atmosphere in the infrared spectrum,the influence of the water vapor environment on the low-temperature optical system,and the short observation period.This article provides a low-cost,miniaturized spacebased infrared optical system solution,which can achieve high signal-to-noise ratio detection.By acquiring real-time luminosity changes,the stellar structure changes during the red giant period can be deduced to understand the evolution of stars.The main tasks of this article: 1)Verify the background radiation model of the lowtemperature infrared optical system itself,and perform quantitative calculations on the background radiation of the system itself;2)Verify the possibility of the realization of the low-temperature infrared optical system on the microsatellite platform,and verify the feasibility of infrared astronomical observations;3)Verify the installation,adjustment and processing possibilities of the low-temperature optical system,provide a new solution for low-cost infrared astronomical observations,verify the feasibility of the infrared system's stray light suppression solution,and lay the foundation for the future development of low-temperature infrared optical systems.This paper mainly carries out related research work from the following aspects:First of all,we will investigate the current status of domestic and foreign related research,summarize the current development status and trend of space infrared astronomy,and propose the research direction and research content of this article.Secondly,starting from task requirements and signal-to-noise ratio,a calculation model of signal intensity and background radiation within 0.9?m?5?m was established,and related influencing factors were analyzed and compared.After selecting the initial structure of the optical system,combined with the domestic detector,the operating parameters of the camera at a signal-to-noise ratio of 100(tenth magnitude)are calculated,and the operating temperature of the system is 130 K,the entrance pupil aperture is 80 mm,and the integration time is 160 s.parameter.Calculate the initial structure parameters,optimize the optical design and athermalized design,and realize the 110K?130K athermalized design through the matching of opto-mechanical materials;through the secondary imaging,the matching efficiency of the cold aperture of the system in the full field of view is greater than 98%;for normal temperature Assembling the problem of low-temperature use,a solution to the compensation of the correction mirror at room temperature is proposed.Carry out engineering analysis and stray light analysis.The new type of light blocking ring used has twice the stray light suppression ability than the general type.At the same time,based on the established model,the system's own thermal radiation is simulated and analyzed,and the optical components and mechanical structure of its own background Radiation will not affect the signal-to-noise ratio of the system,and the system has a certain inhibitory effect on external stray light radiation.Based on the mission requirements for the seismic observation of red giant stars,this paper takes the low-temperature infrared optical system as the research content,and uses the cubic star platform to design the coaxial reflex secondary imaging optical system,which meets the low temperature,wide spectrum,and large relative aperture infrared Astronomical observation requirements provide a miniaturized solution for infrared astronomical observation.