Search for superheavy-element decay in samples of Madagascar monazite

Two samples of Madagascar monazite from the same geological formation as the biotite studied by Gentry et al. were examined by using a neutron multiplicity counter capable of detecting binary or ternary spontaneous fission decay in any element. No events characteristic of spontaneous fission decay of superheavy elements were found. Derived limits indicate that if superheavy elements were present, then their spontaneous fission half-lives must be extremely long or their concentrations extremely small. (AIP)