AI 中文总结
本文针对超导转变边缘传感器所需的毫米波冷负载进行研究，设计制造了4 - 20K毫米波冷负载原型，制作并研究两种吸收器原型，通过模拟和测量筛选，发现CR - 110和Stycast 2850FT复合材料有前景，为后续低温评估提供依据，相关性能待进一步测量确定。
AI 中文摘要
超导转变边缘传感器（TESs）是宇宙微波背景（CMB）观测的关键探测器，需要稳定且可调的毫米波冷负载进行光效率校准。本文介绍了一种4 - 20K毫米波冷负载原型的设计、制造和初步特性表征，该原型旨在集成到稀释制冷机的1K阶段，并用于后续40/90GHz CMB TES校准实验。制作并研究了两种基于商用CR - 110和Stycast 2850FT复合材料的吸收器原型。模拟结果表明，两种吸收器结构在目标频段均具有小的预测稳态温度梯度和低的垂直入射反射率。室温下的S11测量仅用于筛选低反射率冷负载原型，测量结果与电磁模拟结果基本一致。Stycast 2850FT复合材料的测量S11与商用吸收器TK RAM相当。此外，为探索更易获得的替代吸收材料，对TIE280 - 25AB进行了电磁参数测量和初步评估。基于测量参数，TIE280 - 25AB金字塔形吸收器结构在33 - 110GHz范围内的模拟S11与CR - 110和Stycast 2850FT复合材料相当。这些结果表明CR - 110和Stycast 2850FT复合材料是后续低温评估的有前景的吸收器。绝对低温发射率、有效辐射温度和TES校准性能仍有待通过未来的低温辐射测量和基于TES的光功率测量来确定。
英文摘要
Superconducting transition-edge sensors (TESs) are crucial detectors for cosmic microwave background (CMB) observations and require stable and tunable millimeter-wave cold loads for optical-efficiency calibration. This work presents the design, fabrication, and preliminary characterization of a 4-20 K millimeter-wave cold load prototype intended for integration into the 1 K stage of a dilution refrigerator and subsequent 40/90 GHz CMB TES calibration experiments. Two absorber prototypes based on commercially available CR-110 and a Stycast 2850FT composite were fabricated and studied. Simulation results show that both absorber structures exhibit small predicted steady-state temperature gradients and low normal-incidence reflectance in the target frequency bands. Room-temperature S11 measurements were used only to screen low-reflectance cold load prototype, and the measured results generally agree with the electromagnetic simulations. The measured S11 of the Stycast 2850FT composite is comparable to that of the commercial absorber TK RAM. Additionally, to explore a more readily obtainable alternative absorber material, TIE280-25AB was preliminarily evaluated by measuring its electromagnetic parameters. Based on the measured parameters, the simulated S11 of the TIE280-25AB pyramidal absorber structure is comparable to those of CR-110 and the Stycast 2850FT composite over 33-110 GHz. These results identify CR-110 and the Stycast 2850FT composite as promising absorbers for subsequent cryogenic evaluation. The absolute low-temperature emissivity, effective radiation temperature, and TES calibration performance remain to be established through future cryogenic radiometric and TES based optical-power measurements.
