Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Silicon emissivity as a function of temperature   In this paper we present the temperature-dependent emissivity of a silicon
sample, estimated from its cool-down curve in a constant low temperature
environment ($\approx$ 82K). The emissivity value follow a linear dependency in
the 120-260 K temperature range. This result is of great interest to the LIGO
Voyager gravitational wave interferometer project since it would mean that no
extra high thermal emissivity coating on the test masses would be required in
order to cool them down to 123 K. The results presented here indicate that bulk
silicon itself can have sufficient thermal emissivity in order to cool the 200
kg LIGO Voyager test masses only by radiation in a reasonable short amount of
time (less than a week). However, it is still not clear if the natural
emissivity of silicon will be sufficient to maintain the LIGO Voyager test
masses at the desired temperature (123 K) while removing power absorbed by the
test masses. With the present results, a black coating on the barrel surface of
the test masses would be necessary if power in excess of 6 W is delivered.
However, the agreement we found between the hemispherical emissivity obtained
by a theory of semi-transparent Silicon and the obtained experimental results
makes us believe that the LIGO Voyager test masses, because of their
dimensions, will have effective emissivities around 0.7, which would be enough
to remove about 8.6 W (7.5 W) for a shield at 60 K (80K). This hypothesis may
be confirmed in the near future with new measurements.

31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn