On the γ-spectrum following225Ac α-decay

Abstract: The decay of a²²⁵Ac source in equilibrium mixture with its decay products was investigated using high-resolution HP/Ge/ detectors. Energies and intensities of more than 78 gamma-photons were measured with an improved accuracy; 44 of them are reported for the first time. A tentative²²¹Fr level scheme was built on the basis of good energy sum relationships; seven new²²¹Fr excited levels are proposed at 496.9, 570.9, 603.5, 630.7, 637.7, 649.0 and 758.9 keV.