Hot electron heatsinks for microwave attenuators below 100 mK
Abstract
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-μm thick conducting copper heatsinks in between 10-μm 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 Tn ∼ 50 mK was obtained for small dissipated powers (Pd<1 nW) in the attenuator. For higher dissipated powers, we find Tn∝Pd1/4.4, with Pd=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 Tn for the same dissipated power, when compared to a previous design without interleaved heatsinks.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 15, 2019
- Source ID
- 10.1063/1.5097369
Entities
People
- B. S. Palmer
- F. C. Wellstood
- Jay C LeFebvre
- Jen-hao Yeh
- Rui Zhang
- Shavindra P Premaratne
- Yizhou Huang
Organizations
- Joint Quantum Institute
- United States Department of Defense
- University of Maryland