A 10 mK hermetic cell for eliminating parasitic heating in cryogen-free dilution refrigerators

TL;DR

This paper introduces a hermetic cell for cryogen-free dilution refrigerators that effectively eliminates parasitic heating, enabling ultra-low temperature experiments with minimal environmental heat interference.

Contribution

The paper presents a novel hermetic cell design that significantly improves thermal isolation in cryogen-free dilution refrigerators, verified by resonance frequency measurements at millikelvin temperatures.

Findings

Resonance frequency shows expected logarithmic temperature dependence down to 10 mK.

Hermetic shielding outperforms simpler shields with no visible gaps.

Effective parasitic heat elimination enhances low-temperature experimental accuracy.

Abstract

Cryogen-free dilution refrigerators generally simplify low temperature research but some types of samples, including superconducting qubits and other nanoelectronic devices, are affected by environmental heat sources such as stray photons or residual helium. We present the design and performance of a hermetic cell installed on the mixing chamber plate of a cryogen-free dilution refrigerator. The performance was quantified by measuring the dependence of the resonance frequency of a mechanical oscillator installed inside the cell on the mixing chamber temperature down to 10 mK. We found the expected logarithmic temperature dependence of the resonance frequency down to the lowest temperatures, demonstrating that the efficiency of the hermetic shield is significantly better than that of a simpler shield with no visible gaps.