Half-Life Determination Of Short-Lived Nuclear Levels In Np-237 (59.54 Kev), Pa-233 (86.47 Kev) And Ac-227 (27.37 Kev)

New half-life values for isomeric states in Np-237, Pa-233 and Ac-227 were measured by means of 4 pi alpha(LS)-gamma coincidence counting with digital data acquisition. A careful assessment of uncertainties was carried out, and the new results are found to be much more precise than any previous measurement result. The half-lives were found to be T-1/2 (Np-237, E = 59.54 keV) = (67.86 +/- 0.09) ns, T-1/2(Pa-233, E = 86.47 keV) = (36.44 +/- 0.10) ns and T-1/2 Ac-227, E = 27.37 keV) = (38.56 +/- 0.15) ns, respectively. A comprehensive study of literature data was undertaken for a new data evaluation that includes the results from this work.