Development of Semi-rigid Superconducting Coaxial Cables with Clad Central Conductor for Low-Noise Experiments
Development of Semi-rigid Superconducting Coaxial Cables with Clad Central Conductor for Low-Noise Experiments
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用于低噪声实验的包层中心导体半刚性超导同轴电缆的开发
DOI：
10.1007/s10909-018-2044-7
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发表时间：
2018
影响因子：
2
通讯作者：
Kasai S.
中科院分区：
文献类型：
--
作者：
Kushino A.;Okuyama T.;Kasai S.
在这项研究中，半刚性同轴电缆的外径小于1毫米的低温探测器的读出开发。一个双层结构，包括一个超导体包覆正常导体被用于中心导体。这种类型的结构可以表现出低通滤波特性并降低高频噪声。为了使用这种类型的滤波电缆获得高衰减沿着低导热性，使用不锈钢（SUS 304）来包覆NbTi中心导体，因为与常规使用的合金CuNi相比，不锈钢具有高电阻率。在本研究中考虑的半刚性电缆具有0.86 mm的直径，并且由包覆有厚度为13的SUS 304的NbTi中心导体、SUS 304外导体和聚四氟乙烯绝缘体组成。测量了该电缆的低温（2-8 K）热导率，发现其略高于整个中心导体使用SUS 304的相同尺寸的半刚性电缆的热导率。此外，在150 MHz至10 GHz的频率范围内测量的衰减非常大，并且没有观察到由于超导NbTi而导致的低于约1 GHz的预期低衰减。从SEM观察和EDS分析中发现，中心导体的NbTi区域包含来自SUS 304的尺寸近似的晶粒，这可能是观察到的大衰减的原因。
In this study, semi-rigid coaxial cables with an outer diameter of less than 1 mm were developed for the readout of low-temperature detectors. A bilayer structure comprising a superconductor clad with a normal conductor was used for the central conductor. Structures of this type can exhibit low-pass filtering characteristics and reduce high-frequency noise. To obtain high attenuation along with low thermal conductance using this type of filtering cable, stainless steel (SUS304) was used to clad the NbTi central conductor because it has a high electrical resistivity compared to that of the conventionally used alloy CuNi. The semi-rigid cable considered in this study has a diameter of 0.86 mm and consists of a NbTi central conductor clad with SUS304 with a thickness of 13, a SUS304 outer conductor, and a polytetrafluoroethylene insulator. The low-temperature (2–8 K) thermal conductance of this cable was measured and found to be slightly higher than that of a semi-rigid cable of the same dimensions using SUS304 for the entire central conductor. Additionally, the attenuation measured in the frequency range of 150 MHz to 10 GHz was very large, and the expected low attenuation below approximately 1 GHz due to the superconducting NbTi was not observed. From SEM observation and EDS analysis, it was found that the NbTi region of the central conductor contained grains of approximatelyin size derived from the SUS304, which may have been the cause of the observed large attenuation.