Phased array feeds (PAFs), which illuminate the dish with digitally synthesized beams instead of separated horns, provide the capability for wider and continuous field-of-view surveys. As a promising technology for next generation radio telescopes, PAFs will provide the Qi Tai Telescope (QTT), which will be next world-class fully steerable radio telescope, an opportunity of reaching several cutting-edge science goals. This paper presents a brief introduction of the wideband PAF for QTT, and the detailed design and simulation of the cryogenic system. Based on this design, a scaled prototype of the spherical vacuum window, which is the key part of the cryogenic system, has been built and the performance is verified.

相控阵馈源 (PAF) 用数字合成光束而不是分离的喇叭照射盘子，提供了进行更广泛和连续视场调查的能力。作为下一代射电望远镜的一项有前途的技术，PAFs 将提供齐泰望远镜（QTT），这将是下一个世界级的完全可控射电望远镜，这是实现几个尖端科学目标的机会。本文简要介绍了用于 QTT 的宽带 PAF，以及低温系统的详细设计和仿真。以此设计为基础，构建了低温系统关键部件球形真空窗的比例样机，并对其性能进行了验证。