Accurate masses of unstable rare-earth isotopes by ISOLTRAP

Direct mass measurements of neutron-deficient rare-earth isotopes in the vicinity of 146Gd were performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. This paper reports on the measurement of more than 40 isotopes of the elements praseodymium, neodymium, promethium, samarium, europium, dysprosium and holmium, that have been measured with a typical accuracy of δm ≈ 14 keV. An atomic mass evaluation has been performed taking into account other experimental mass values via a least-squares adjustment. The results of the adjustment are discussed.