Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surrounding material effect on measurement of thunderstorm-related
  neutrons   Observations of strong flux of low-energy neutrons were made by
$^{3}\mathrm{He}$ counters during thunderstorms [Gurevich et al (Phys. Rev.
Lett. 108, 125001, 2012)]. How the unprecedented enhancements were produced
remains elusive. To better elucidate the mechanism, a simulation study of
surrounding material impacts on measurement by $^{3}\mathrm{He}$ counters was
performed with GEANT4. It was found that unlike previously thought, a
$^3\mathrm{He}$ counter had a small sensitivity to high-energy gamma rays
because of inelastic interaction with its cathode-tube materials (Al or
stainless steel). A $^{3}\mathrm{He}$ counter with the intrinsic small
sensitivity, if surrounded by thick materials, would largely detect
thunderstorm-related gamma rays rather than those neutrons produced via
photonuclear reaction in the atmosphere. On the other hand, the counter, if
surrounded by thin materials and located away from a gamma-ray source, would
observe neutron signals with little gamma-ray contamination. Compared with the
Gurevich measurement, the present work allows us to deduce that the
enhancements are attributable to gamma rays, if their observatory was very
close to or inside a gamma-ray emitting region in thunderclouds.

32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn