Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Absolute Energy Calibration with the Neutron-Activated Liquid-Source
  System at BaBar's CsI(Tl) Calorimeter   The electro-magnetic calorimeter at the BaBar detector, part of the
asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV
to 8 GeV with good resolution. The calorimeter is calibrated at the low energy
end with 6.13 MeV photons obtained from a liquid source system. During the
calibration, a fluorine-rich liquid is activated via a neutron generator and
pumped past the front of the calorimeter's crystals. Decays that occur in front
of the crystals emit photons of well-defined energy, which are detected in the
crystals with the regular data acquisition system. The liquid source system
adds only very little material in front of the calorimeter, needs nearly no
maintenance, and allows operation at the switch of a key with minimal safety
hazards. The report describes the system, presents calibration results obtained
from its operation since 1999, shows the crystals' loss of light yield due to
radiation damage, and shares experiences gained over the years.

15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys