Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new model of cosmogenic production of radiocarbon 14C in the
  atmosphere   We present the results of full new calculation of radiocarbon 14C production
in the Earth atmosphere, using a numerical Monte-Carlo model. We provide, for
the first time, a tabulated 14C yield function for the energy of primary cosmic
ray particles ranging from 0.1 to 1000 GeV/nucleon. We have calculated the
global production rate of 14C, which is 1.64 and 1.88 atoms/cm2/s for the
modern time and for the pre-industrial epoch, respectively. This is close to
the values obtained from the carbon cycle reservoir inventory. We argue that
earlier models overestimated the global 14C production rate because of outdated
spectra of cosmic ray heavier nuclei. The mean contribution of solar energetic
particles to the global 14C is calculated as about 0.25% for the modern epoch.
Our model provides a new tool to calculate the 14C production in the Earth's
atmosphere, which can be applied, e.g., to reconstructions of solar activity in
the past.

7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci