Dry demagnetization cryostat for sub-millikelvin helium experiments: Refrigeration and thermometry

Journal Article · Fri Aug 01 04:00:00 EDT 2014 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4891619· OSTI ID:22327830

Kaikkonen, J. -P.; Hakonen, P. J.; Savin, A. ^[1]; Blaauwgeers, R. ^[2]

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1. Low Temperature Laboratory, O.V. Lounasmaa Laboratory, Aalto University, FI-00076 AALTO (Finland)
2. BlueFors Cryogenics Ltd, Arinatie 10, 00370 Helsinki (Finland)

We demonstrate successful “dry” refrigeration of quantum fluids down to T = 0.16 mK by using copper nuclear demagnetization stage that is pre-cooled by a pulse-tube-based dilution refrigerator. This type of refrigeration delivers a flexible and simple sub-mK solution to a variety of needs including experiments with superfluid {sup 3}He. Our central design principle was to eliminate relative vibrations between the high-field magnet and the nuclear refrigeration stage, which resulted in the minimum heat leak of Q = 4.4 nW obtained in field of 35 mT. For thermometry, we employed a quartz tuning fork immersed into liquid {sup 3}He. We show that the fork oscillator can be considered as self-calibrating in superfluid {sup 3}He at the crossover point from hydrodynamic into ballistic quasiparticle regime.

• OSTI ID: 22327830
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 8 Vol. 85; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
COPPER
DEMAGNETIZATION
EQUIPMENT
HELIUM 3
QUARTZ
REFRIGERATION
SUPERFLUIDITY