Since the first neutrinos were detected more than four decades ago, researchers have sought better ways of detecting these elusive, high-energy particles that originate from nuclear reactors and outer space.Japan and the US have teamed up to construct the Kamioka liquid scintillator antineutrino detector called KamLand, an underground facility designed to detect antineutrinos, the antimatter counterparts of neutrinos. The aim is to distinguish between neutrinos originating from Japan's 51 power reactors and those traveling from the sun. Physicists from both countries hope to add to the mounting evidence that these ghostly particles have mass.