Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Commissioning of the J-PET detector in view of the positron annihilation
  lifetime spectroscopy   The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET device
built from plastic scintillators. It is a multi-purpose detector designed for
medical imaging and for studies of properties of positronium atoms in porous
matter and in living organisms. In this article we report on the commissioning
of the J-PET detector in view of studies of positronium decays. We present
results of analysis of the positron lifetime measured in the porous polymer.
The obtained results prove that J-PET is capable of performing simultaneous
imaging of the density distribution of annihilation points as well as positron
annihilation lifetime spectroscopy.

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The categories of this paper are: math
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
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The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
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The categories of this paper are: stat
28
The categories of this paper are: alg-geom