Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radiation hardness qualification of PbWO4 scintillation crystals for the
  CMS Electromagnetic Calorimeter   Ensuring the radiation hardness of PbWO4 crystals was one of the main
priorities during the construction of the electromagnetic calorimeter of the
CMS experiment at CERN. The production on an industrial scale of radiation hard
crystals and their certification over a period of several years represented a
difficult challenge both for CMS and for the crystal suppliers. The present
article reviews the related scientific and technological problems encountered.

2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph