Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Ultra-High Energy Cosmic Ray Spectrum Measured by the Telescope
  Array's Middle Drum Detector   The Telescope Array's Middle Drum fluorescence detector was constructed using
refurbished telescopes from the High Resolution Fly's Eye (HiRes) experiment.
As such, there is a direct comparison between these two experiments'
fluorescence energy spectra. An energy spectrum has been calculated based on
one year of collected data by the Middle Drum site of Telescope Array and
agrees well with the HiRes monocular spectra. The quality of the Middle Drum
results has also been determined to show good agreement.

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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
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The categories of this paper are: stat
11
The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
30
The categories of this paper are: q-alg