Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Development of a near-5-Kelvin, cryogen-free, pulse-tube
  refrigerator-based scanning probe microscope   We report the design and performance of a cryogen-free, pulse-tube
refrigerator (PTR)-based scanning probe microscopy (SPM) system capable of
operating at the base temperature of near 5K. We achieve this by combining a
home-made interface design between the PTR cold head and the SPM head, with an
automatic gas-handling system. The interface design isolates the PTR vibrations
by a combination of polytetrafluoroethylene and stainless-steel bellows, and by
placing the SPM head on a passive vibration isolation table via two cold stages
that are connected to thermal radiation shields using copper heat links. The
gas-handling system regulates the helium heat-exchange gas pressures,
facilitating both the cool down to and the maintenance of the base temperature.
We discuss the effects of each component using measured vibration,
current-noise, temperature, and pressure data. We demonstrate that our SPM
system performance is comparable to known liquid-helium-based systems with the
measurements of the superconducting gap spectrum of Pb, atomic-resolution
scanning tunneling microscopy image and quasiparticle interference pattern of
Au(111) surface, and non-contact atomic force microscopy image of NaCl(100)
surface. Without the need for cryogen refills, the current SPM system enables
uninterrupted low-temperature measurements.

22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an