Beta EmitterNp238. I. Beta Spectroscopy

The beta decay of ${\mathrm{Np}}^{238}$ has been studied with several beta spectrometers. In addition to the known conversion lines corresponding to transitions of energies now determined as 44.0, 102.2, 986, and 1029 kev, new conversion lines, corresponding to transitions of 942 and 927 kev were found. These transitions indicate the presence of closely spaced levels at higher excitation energies. Intensities of conversion lines and beta groups were determined and compared with previous work. Fermi-Kurie plots confirm the allowed shape of the hard beta group (1.25 Mev) and give indication of complexity in the soft beta group (0.27 Mev). The energy deviations of the ground rotational band levels from the simple rotational energy formula are discussed.