Design and simulation of vacuum feedthrough and its flange for mosaic cryogenic FPA

Presently, the field of astronomy is transitioning towards the analysis of extensive datasets and all-encompassing sky surveys, moving away from the traditional study of individual celestial bodies. The imaging terminal of large field of view sky survey telescopes is typically equipped with a splicing camera consisting of CCD/COMS detectors. In order to enhance the signal-to-noise ratio of imaging and mitigate dark current, the splicing CCD imaging surface must be enclosed within a vacuum Dewar and cooled to temperatures ranging from -80 to -100 ℃. This poses a significant challenge in facilitating the electrical signal feeding and readout of multiple detectors within a low-temperature vacuum environment. This study employs glass sintering and bonding techniques in conjunction with thermodynamic simulation analysis to achieve the transmission of more than 1600 signals through a constrained flange surface. Environmental adaptability is maintained through the thermal matching of materials, and the introduction of a stress relief groove mitigates the impact of flange surface deformation on bonding positions under vacuum conditions. Following multiple rounds of temperature loop test, it was determined that the leakage rate of the vacuum feedthrough component can be controlled to ≤ 1E-9 Pa • m ³/s. The high-density signal vacuum penetration scheme proposed in this study holds important implications for the design and signal extraction processes of multi-detector splicing focal plane cameras.