Development of Semi-Rigid Superconducting Coaxial Cables as Low-Pass Filters
Development of Semi-Rigid Superconducting Coaxial Cables as Low-Pass Filters
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作为低通滤波器的半刚性超导同轴电缆的开发
DOI：
10.1109/tasc.2016.2645161
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发表时间：
2017
影响因子：
1.8
通讯作者：
Soichi Kasai
中科院分区：
文献类型：
--
作者：
Akihiro Kushino;Soichi Kasai
我们开发了薄的半刚性同轴电缆作为读出噪声滤波器在低温实验中使用。这里报道的电缆具有0.86 mm的外径，并且由作为无缝外导体的标准白铜（CuNi）合金和作为介电材料的聚四氟乙烯（PTFE）组成。内导体为超导铌钛合金（NbTi），表面覆有厚度为0、13或38 μm的CuNi覆层。在低温下测量电缆的热导率和传输特性，并与常规CuNi半刚性电缆的热导率和传输特性进行比较。在1.4至8.4 K之间，热导率与传统电缆相似，因为估计包层的贡献很小。另一方面，在约3 K下测量，在高达10 GHz的高频下的衰减的不同之处在于，截止频率随着CuNi覆层厚度的减小而增加。当包层厚度为38 μm时，1 m长电缆的3 dB截止频率为100 MHz，而当包层厚度为13 μm时，3 dB截止频率为500 MHz。因此，这种类型的半刚性电缆可以用作低通滤波器，其衰减特性可以通过改变包覆层的厚度来定制。
We developed thin semi-rigid coaxial cables for use as readout noise filters in low temperature experiments. The cables reported here had an outer diameter of 0.86 mm, and consisted of a standard cupronickel (CuNi) alloy as a seamless outer conductor and polytetrafluoroethylene (PTFE) as a dielectric material. The inner conductor was superconducting niobium-titanium (NbTi) covered by a CuNi cladding layer with a thickness of 0, 13, or 38 μm. The thermal conductance and transmission properties for the cables were measured at cryogenic temperatures and compared to those for a conventional CuNi semi-rigid cable. Between 1.4 and 8.4 K, the thermal conductance was similar to that for the conventional cable because the contribution from the cladding was estimated to be small. On the other hand, measured at about 3 K, the attenuation at high frequency up to 10 GHz differed in that the cutoff frequency increased with decreasing CuNi cladding thickness. For a cladding thickness of 38 μm, the 3 dB cutoff frequency for a 1-m-long cable was 100 MHz, whereas for a cladding thickness of 13 μm, it was 500 MHz. This type of semi-rigid cable can, therefore, be used as a low-pass filter whose attenuation characteristics can be tailored by changing the thickness of the cladding layer.