Guedes, S.Hadler, J. C.Iunes, P. J.Burke, A. K.Kazazu, M. H.Sarkis, JESPaulo, SRTello, C. A.2014-05-202014-05-202002-07-01Journal of Radioanalytical and Nuclear Chemistry. Dordrecht: Kluwer Academic Publ, v. 253, n. 1, p. 73-76, 2002.0236-5731http://hdl.handle.net/11449/33586We have developed a methodology for measuring the decay constant of the spontaneous fission of U-238, lambda(f), using nuclear particle track detectors where thermal neutron irradiation is unnecessary. This methodology is based on the fact that the radiation damage caused by spontaneous fission of trans-uranium elements bearing a mass number close to 238 are similar to U-238 spontaneous-fission ones. Loading a thick source of uranium (thickness greater than the fission fragment range) with a small amount of a suitable trans-uranium element (for instance, Pu-242, which presents a spontaneous fission half-life of 6.75(.)10(10) y), it is possible to determine the observation efficiency of a particle-track detector for fission fragments. Procedures concerning our thick source manufacture and uniformity tests of the trans-uranium distribution are also presented. These results make it possible for the exposure of thick uranium sources (without trans-uranium element) to lead to a lambda(f) value.73-76engArtigo10.1023/A:1015860400376WOS:000176190300010Acesso restrito