Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for cosmic dark matter by means of ultra high purity NaI(Tl)
  scintillator   The dark matter search project by means of ultra high purity NaI(Tl)
scintillator is now underdevelopment. An array of large volume NaI(Tl)
detectors whose volume is 12.7 cm$\phi\times$12.7 cm is applied to search for
dark matter signal. To remove radioactive impurities in NaI(Tl) crystal is one
of the most important task to find small number of dark matter signals. We have
developed high purity NaI(Tl) crystal which contains small amounts of
radioactive impurities, $<4$ ppb of $^{nat}$K, 0.3 ppt of Th chain, 58
$\mu$Bq/kg of $^{226}$Ra and 30 $\mu$Bq/kg of $^{210}$Pb. Future prospects to
search for dark matter by means of a large volume and high purity NaI(Tl)
scintillator is discussed.

15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci