Electron capture decay of 237Pu, 235Np, and 236Np

Decay schemes of 45.3-d 237Pu and 1.55 x 105 yr 236Np have been investigated by measuring their γ ray and conversion electron spectra with a 5-cm2 x 1-cm Ge detector and a cooled Si(Li) spectrometer, respectively. Intensities of γ rays, x rays, and conversion electrons have been determined and these have been used to derive logft values for EC and β- transitions. In addition to confirming previously known level schemes in 237Np and 236U, the energies of the 4+→2+ and 6+→4+ transitions in the 236Pu ground state band have been determined. Relative intensities of x rays in the decay of 235Np have also been measured