Observation of Reactor Antineutrinos with a Rapidly-Deployable Surface-Level Detector

We deployed a small, 80kg, neutrino 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 of 2880 events 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 the first observation of the positron spectrum in a small, surface-deployed detector and the first observation of reactor neutrinos with a street-legal, mobile neutrino detector.