de Wit Martin, Welker Gesa, Heeck Kier, Buters Frank M, Eerkens Hedwig J, Koning Gert, van der Meer Harmen, Bouwmeester Dirk, Oosterkamp Tjerk H
Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
Rev Sci Instrum. 2019 Jan;90(1):015112. doi: 10.1063/1.5066618.
We present the design and implementation of a mechanical low-pass filter vibration isolation used to reduce the vibrational noise in a cryogen-free dilution refrigerator operated at 10 mK, intended for scanning probe techniques. We discuss the design guidelines necessary to meet the competing requirements of having a low mechanical stiffness in combination with a high thermal conductance. We demonstrate the effectiveness of our approach by measuring the vibrational noise levels of an ultrasoft mechanical resonator positioned above a superconducting quantum interference device. Starting from a cryostat base temperature of 8 mK, the vibration isolation can be cooled to 10.5 mK, with a cooling power of 113 µW at 100 mK. We use the low vibrations and low temperature to demonstrate an effective cantilever temperature of less than 20 mK. This results in a force sensitivity of less than 500 zN/Hz and an integrated frequency noise as low as 0.4 mHz in a 1 Hz measurement bandwidth.
我们展示了一种用于减少在10 mK下运行的无液氦稀释制冷机中振动噪声的机械低通滤波器隔振装置的设计与实现，该制冷机用于扫描探针技术。我们讨论了满足低机械刚度与高热导率这两个相互竞争要求所需的设计准则。我们通过测量位于超导量子干涉装置上方的超软机械谐振器的振动噪声水平，证明了我们方法的有效性。从低温恒温器的8 mK基础温度开始，隔振装置可冷却至10.5 mK，在100 mK时冷却功率为113 μW。我们利用低振动和低温展示了有效悬臂温度低于20 mK。这导致在1 Hz测量带宽内的力灵敏度小于500 zN/Hz，积分频率噪声低至0.4 mHz。
