Dissipative cryogenic filters with zero dc resistance
Dissipative cryogenic filters with zero dc resistance
复制标题
DOI：
10.1063/1.2835716
复制
发表时间：
2008-01-01
影响因子：
1.6
通讯作者：
Moler, Kathryn A.
中科院分区：
文献类型：
--
作者：
Bluhm, Hendrik;Moler, Kathryn A.
作者设计、实现并测试了零直流电阻低温射频滤波器，该滤波器基于电阻护套内的超导铁芯导线。超导磁芯允许低频电流通过，耗散可以忽略不计。高于截止频率的信号由于趋肤深度小而在电阻部分耗散。滤波器由用铜带屏蔽的双绞线对组成。在大约1ghz以上，衰减以根ω为指数，这是基于趋肤深度的射频滤波器的典型特征。通过使用每条线10nf的附加电容，可以获得10mhz以上至少45db的衰减。因此，在稀释制冷机中保持混合室温度的单级过滤足以将室温黑体辐射衰减到约10 MHz以上的10 mK水平。(c) 2008年美国物理研究所。
The authors designed, implemented, and tested cryogenic rf filters with zero dc resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1 GHz, the attenuation is exponential in root omega, as typical for skin depth based rf filters. By using additional capacitors of 10 nF per line, an attenuation of at least 45 dB above 10 MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10 mK above about 10 MHz. (c) 2008 American Institute of Physics.