Remote Monitoring of Reactors: The Watchman Project In 2001, Bernstein, West and Gupta [i] described a possible campaign to monitor nuclear fission reactions over large distances using arrays of Super-Kamiokande (Super-

In 2001, Bernstein, West and Gupta [i] described a possible campaign to monitor nuclear fission reactions over large distances using arrays of Super-Kamiokande (SuperK) type water Cherenkov detectors, modified to include neutron-capture elements such as gadolinium. This modification would allow sensitivity to reactor and other low energy antineutrinos through the inverse beta decay interaction. In 2004 Beacom and Vagins [ii] identified a suitable water soluble gadolinium compound, and introduced the GADZOOKS! proposal to put gadolinium into Super-K. This would effectively transform SuperK into the world’s largest antineutrino detector, fifty times larger than the KamLAND scintillator detector. More recently, there have been the proposals to include gadolinium doping in the water Cherenkov LBNE detector at Homestake, and the Hyper-K detector in Japan. Both the fundamental neutrino physics community, with interests in supernova detection, proton decay and neutrino oscillation physics, and the applied antineutrino/non-proliferation community are interested in water Cherenkov technology. The latter community envisions the possibility of discovery or exclusion of small plutonium production reactors at hundreds of kilometer standoff, by looking for changes in the measured antineutrino flux in large antineutrino detectors. For all of these goals, gadolinium doped water detectors appear to be the most tractable, scalable approach to achieving the required detector sizes.