Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Development of Low Radioactive Molecular Sieves for Ultra-Low Background
  Particle Physics Experiment   This study develops low radioactive molecular sieves (MS) for ultra-low
background particle physics experiment. The manufactured MS is of type 4A.
$^{226}$Ra and $^{232}$Th have concentrations of about 57 and 198 mBq/kg,
respectively, measured by applying high-purity germanium (HPGe) measurement.
The reduction of the radioactivity from the commercial one is about 99 and 97
percent for $^{226}$Ra and $^{232}$Th, respectively. Furthermore, the radon
emanation rate from MS filter is about 2.1 mBq, which is measured by utilizing
pin-photo type radon detector. This developed MS is expected to remove the
impurity from the noble gas, in which low radioactivity is needed such as dark
matter search experiment.

22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin