Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Absolute hydrogen depth profiling using the resonant
  $^{1}$H($^{15}$N,$\alpha\gamma$)$^{12}$C nuclear reaction   Resonant nuclear reactions are a powerful tool for the determination of the
amount and profile of hydrogen in thin layers of material. Usually, this tool
requires the use of a standard of well-known composition. The present work, by
contrast, deals with standard-less hydrogen depth profiling. This approach
requires precise nuclear data, e.g. on the widely used
$^{1}$H($^{15}$N,$\alpha\gamma$)$^{12}$C reaction, resonant at 6.4\,MeV
$^{15}$N beam energy. Here, the strongly anisotropic angular distribution of
the emitted $\gamma$-rays from this resonance has been re-measured, resolving a
previous discrepancy. Coefficients of (0.38$\pm$0.04) and (0.80$\pm$0.04) have
been deduced for the second and fourth order Legendre polynomials,
respectively. In addition, the resonance strength has been re-evaluated to
(25.0$\pm$1.5)\,eV, 10\% higher than previously reported. A simple working
formula for the hydrogen concentration is given for cases with known
$\gamma$-ray detection efficiency. Finally, the absolute approach is
illustrated using two examples.

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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: econ
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics