Towards above-ground antineutrino detectors for cooperative monitoring: Background radiation studies

We describe an assembly of detectors that quantifies the background radiation present at potential above ground antineutrino detector development and deployment sites. Antineutrino detectors show great promise for safeguard applications in directly detecting the total fission rate as well as the change in fissile content of nuclear power reactors. One major technical challenge that this safeguard application must overcome is the ability to distinguish signals from antineutrinos originating in the reactor core from noise due to background radiation created by terrestrial and cosmogenic sources. To date, existing detectors increase their ability to distinguish antineutrino signals by being surrounded with significant shielding and being placed underground. For the safeguard’s agency, this is less than optimal, increasing the overall size and limiting the placement of this system. For antineutrino monitoring to be a widely deployable solution, we must understand the backgrounds found above ground at nuclear power plants that can mimic the antineutrino signal so that these backgrounds can be easily identified, separated, and subtracted rather than shielded. The design, construction, calibration, and results from the deployment of these background detectors at a variety of sites will be presented.