The internal conversion electron spectrum at very low energy, following 237Np decay

A windowless detector has been constructed in order to study electrons of energies below 17 keV in the National Physical Laboratory π√2 β-spectrometer. This detector was used to study the very low energy conversion electrons, emitted following the decay of 237Np. The decay scheme of 237Np requires several low energy transitions to exist in order to be self-consistent, so a search was made for these transitions. Six electron lines were identified as being associated with two transitions in 233Pa. A 36.2 keV transition was conclusively identified for the first time, with a transition probability of 0.012(2) and its multipolarity established, balancing part of the 237Np decay scheme. (orig.)