  We deployed a small, 80kg, antineutrino detector based on solid plastic
scintillator, called MiniCHANDLER for nearly three months at a distance of 25m
from a 2.9GW thermal power reactor core at the North Anna Nuclear Generating
Station. We report the detection of an antineutrino signal resulting from
inverse beta decay at 5.5 sigma significance with no overburden and minimal
shielding. This result also demonstrates that 3D segmentation can be used to
significantly improve the signal to noise ratio, in this case by a factor of 4.
In addition, this measurement represents an observation of the positron
spectrum in a small, surface-deployed detector; this observation of reactor
antineutrinos was achieved with a mobile neutrino detector mounted in an
ordinary, small trailer.
