Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A compact ultra-clean system for deploying radioactive sources inside
  the KamLAND detector   We describe a compact, ultra-clean device used to deploy radioactive sources
along the vertical axis of the KamLAND liquid-scintillator neutrino detector
for purposes of calibration. The device worked by paying out and reeling in
precise lengths of a hanging, small-gauge wire rope (cable); an assortment of
interchangeable radioactive sources could be attached to a weight at the end of
the cable. All components exposed to the radiopure liquid scintillator were
made of chemically compatible UHV-cleaned materials, primarily stainless steel,
in order to avoid contaminating or degrading the scintillator. To prevent radon
intrusion, the apparatus was enclosed in a hermetically sealed housing inside a
glove box, and both volumes were regularly flushed with purified nitrogen gas.
An infrared camera attached to the side of the housing permitted real-time
visual monitoring of the cable's motion, and the system was controlled via a
graphical user interface.

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The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th