Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Results of the BiPo-1 prototype for radiopurity measurements for the
  SuperNEMO double beta decay source foils   The development of BiPo detectors is dedicated to the measurement of
extremely high radiopurity in $^{208}$Tl and $^{214}$Bi for the SuperNEMO
double beta decay source foils. A modular prototype, called BiPo-1, with 0.8
$m^2$ of sensitive surface area, has been running in the Modane Underground
Laboratory since February, 2008. The goal of BiPo-1 is to measure the different
components of the background and in particular the surface radiopurity of the
plastic scintillators that make up the detector. The first phase of data
collection has been dedicated to the measurement of the radiopurity in
$^{208}$Tl. After more than one year of background measurement, a surface
activity of the scintillators of $\mathcal{A}$($^{208}$Tl) $=$ 1.5
$\mu$Bq/m$^2$ is reported here. Given this level of background, a larger BiPo
detector having 12 m$^2$ of active surface area, is able to qualify the
radiopurity of the SuperNEMO selenium double beta decay foils with the required
sensitivity of $\mathcal{A}$($^{208}$Tl) $<$ 2 $\mu$Bq/kg (90% C.L.) with a six
month measurement.

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The categories of this paper are: cond-mat
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: cs
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The categories of this paper are: hep-th
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph