Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Laser calibration system for the CERES Time Projection Chamber   A Nd:YAG laser was used to simulate charged particle tracks at known
positions in the CERES Time Projection Chamber at the CERN SPS. The system was
primarily developed to study the response of the readout electronics and to
calibrate the electron drift velocity. Further applications were the
determination of the gating grid transparency, the chamber position
calibration, and long-term monitoring of drift properties of the gas in the
detector.

8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con