Measurement of reactor neutrinos and backgrounds at the experimental fast reactor JOYO

Recently, a compact neutrino detector has attracted attention as a remote monitor for Plutonium breeding and the R&D has become active in the world. As one of the R&D, anti-neutrinos and backgrounds at fast experimental reactor JOYO site were measured by using 0.76 tons Gd-loaded liquid scintillator in 2007. The detector was set up at 24.3 m away from the reactor core at ground level. Furthermore, a new detector was designed for the next experiment based on the knowledge of backgrounds and the detector performance was evaluated by the Monte Carlo simulation using Geant4. We report the result of JOYO measurement and the study for next experiment.