Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal expansion coefficient of single crystal silicon from 7 K to 293
  K   We measured the absolute lengths of three single crystal silicon samples by
means of an imaging Twyman-Green interferometer in the temperature range from 7
K to 293 K with uncertainties of about 1 nm. From these measurements we extract
the coefficient of thermal expansion with uncertainties in the order of
$1\times 10^{-9} {\rm /K}$. To access the functional dependence of the length
on the temperature usually polynomials are fitted to the data. Instead we use a
physically motivated model equation with 7 fit parameters for the whole
temperature range. The coefficient of thermal expansion is obtained from the
derivative of the best fit. The measurements conducted in 2012 and 2014
demonstrate a high reproducibility and the agreement of two independently
produced samples supports single crystal silicon as reference material for
thermal expansion. Although the results for all three samples agree with each
other and with measurements performed at other institutes, they significantly
differ from the recommended values for thermal expansion of crystalline
silicon.

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The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
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The categories of this paper are: eess
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph