Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dry demagnetization cryostat for sub-millikelvin helium experiments:
  refrigeration and thermometry   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 $^3$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
$^3$He. We show that the fork oscillator can be considered as self-calibrating
in superfluid $^3$He at the crossover point from hydrodynamic into ballistic
quasiparticle regime.

11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con