Hot electron heatsinks for microwave attenuators below 100 mK
Hot electron heatsinks for microwave attenuators below 100 mK
复制标题
用于低于 100 mK 的微波衰减器的热电子散热器
作者：
Jen;Yizhou Huang;Rui Zhang;S. Premaratne;J. LeFebvre;F. Wellstood;B. Palmer
我们展示了为在100MK以下工作而设计的宽带(10 GHz)微波衰减器冷却功率的改进。通过在10-70 nm长、70 nm厚的阻性镍铬元素中交错放置9-10-1微米厚的导电铜散热器，镍铬元素中产生的电热更容易被传导到热沉中，有效地降低了热电子和冷声子之间的热阻。对于安装在20 mK下的20分贝衰减器，对于小损耗功率($P_d<；$1 nW)，最低噪声温度为T_(N)sim$50 mK。对于较高的耗散功率，我们得到了$T_n proto P_{d}^{(1/4.4)}$，其中$P_{d}=$100 nW，对应于90mK的噪声温度。这与系统的热模拟非常一致，与没有交错散热器的先前设计相比，冷却功率提高了近20倍，或者在相同的耗散功率下减少了1.8倍的T_n。
We demonstrate improvements to the cooling power of broad bandwidth (10 GHz) microwave attenuators designed for operation at temperatures below 100 mK. By interleaving 9-$mu$m thick conducting copper heatsinks in between 10-$mu$m long, 70-nm thick resistive nichrome elements, the electrical heat generated in the nichrome elements is conducted more readily into the heatsinks, effectively decreasing the thermal resistance between the hot electrons and cold phonons. For a 20 dB attenuator mounted at 20 mK, a minimum noise temperature of $T_{n} sim$ 50 mK was obtained for small dissipated powers ($P_d <$ 1 nW) in the attenuator. For higher dissipated powers we find $T_n propto P_{d}^{(1/4.4)}$, with $P_{d} =$ 100 nW corresponding to a noise temperature of 90 mK. This is in good agreement with thermal modeling of the system and represents nearly a factor of 20 improvement in cooling power, or a factor of 1.8 reduction in $T_n$ for the same dissipated power, when compared to a previous design without interleaved heatsinks.