1979/04/01 by Kimberly E. Williams, Glenn T. Seaborg · 1 citation
Physics and Astronomy · Chemistry · #Nuclear physics research studies #Radioactive element chemistry and processing #Nuclear Physics and Applications
paper · doi:10.1103/physrevc.19.1794
openalex publication_date 1979/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/07
A new isotope of berkelium has been identified through bombardments of 235U with 11B, 238U with 10B, and 232Th with both 14N and 15N. The new activity decays by electron capture with a half-life of 7.0\ifmmode±\else\textpm\fi1.3 minutes. The \ensuremathα-branching ratio for this isotope is less than 1% and that for spontaneous fission is less than 0.03%. Analysis of the excitation functions, the chemical behavior of the isotope, and the milking of the 242Cm daughter leads to the positive identification of this isotope as 242Bk. A preliminary search was made for 241Bk but was unsuccessful. Examination of the (heavy ion, pxn) (Cm) and (heavy ion, \ensuremathαxn) (Am) transfer products in comparison with the (heavy ion, xn) (Bk) compound nucleus products produced in the above reactions revealed transfer reaction cross sections to be equal to or greater than the compound nucleus cross sections. The data suggest that in some cases the yield of an isotope produced via a pxn or \ensuremathαxn transfer reaction might be higher than its production via an xn compound nucleus reaction.NUCLEAR REACTIONS Compound nucleus, proton and alpha transfer reactions: 235U(10,11B,X)I; 238U(10B,Q)R; 232Th(14,15N,M)T; measured excitation functions for 242Bk; measured \ensuremathσ for 238Am, 239Am, 240Am, 240Cm, 242Cm, 243Bk.