Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Optical Reflector System for the CANGAROO-II Telescope   We have developed light and durable mirrors made of CFRP (Carbon Fiber
Reinforced Plastics) laminates for the reflector of the new CANGAROO-II 7 m
telescope. The reflector has a parabolic shape (F/1.1) with a 30 m^2 effective
area which consists of 60 small spherical mirrors. The attitude of each mirror
can be remotely adjusted by stepping motors. After the first adjustment work,
the re ector offers a point image of about 0.14 degree (FWHM) on the optic
axis. The telescope has been in operation since May 1999 with an energy
threshold of ~ 300 GeV.

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The categories of this paper are: funct-an
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
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The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
3
The categories of this paper are: physics
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The categories of this paper are: stat