  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.
