Search for Superheavy Elements in Nature

The results of a search for elements in the region of atomic number 114 are reported. More than 40 large samples of ores, naturals minerals, and other possible sources have been investigated. The method of detection made use of a large liquid scintillator to detect spontaneous fission events in which unusually large numbers of neutrons are emitted. The apparatus was located in a tunnel under about 250 m of earth shielding in order to reduce the interfering effects of cosmic rays. The limit set for the ratio of half-life/concentration for all the materials tested was greater than ${10}^{23}$ yr/concentration. If the half-life were ${10}^9$ yr this limit would correspond to a concentration of less than ${10}^{-14\mathrm{}}$ moles of superheavy elements per mole of sample.