Qvalues for neutron-rich rubidium and lanthanum isotopes

Measurements of?-endpoint-energies using a magnetic electron separator

“…Further we have compared our Qa-values to those reported by the Tristan group [18,19] 95Rb -65778+61 -65850_+100 -65819+100 -65810_+23 96Rb -61171+57 -61220+ 70 -61186+ 70 -61135__+29 97Rb -58348+81 -58370+ 80 -58332+ 80 -58270-+40 98Rb -54000-1-89 -54180___ 100 -54139-+ 100 -54 040-+ 50…”

Beta-decay energies of neutron-rich nuclei in the mass region 142?A?150

“…The next strong//-branches in the decay of 146La, which populate levels of 925 keV and 961 keV energy in 146Ce, cf. Table 1, have a mean endpoint energy of about 5,700 keV, which is outside the fit interval chosen for the //-singles spectrum in [12]. Therefore, these//-branches do not influence the determination of the endpoint of the spectrum investigated.…”

“…The Q~-value calculated from this low /3-endpoint (Q~=6,175 _+ 100 keV) also disagrees with the result of the direct mass determination of t46Cs, as will be shown below. The Q~-value of 146La was also measured by Brenner et al [12] at TRISTAN. Their value is based upon the fl-endpoint energy of 6,384+50 keV obtained in a /3-singles measurement and upon the endpoint energy of 6,120+30 keV derived from a/3-spectrum measured in coincidence with the 258 keV 7-transition.…”

“…Bengtsson et al [2] and Nazarewicz et al [3], for very neutron-rich nuclei in the vicinity of the proton number Z=56 and neutron number N=90. The present study was undertaken to improve the reliability and accuracy of experimental Q~-values and nuclear masses in this mass region, which have been reported in the past by several groups [4][5][6][7][8][9][10][11][12], in order to check these predictions. For the isobars with A =146 and A =147, which are of special importance in this search for structure effects, new Q~-measurements have been performed at the mass separator OSTIS of the ILL at Grenoble, whereas for the isobaric mass chains with 142_<A_<145 and 148<A<150, the results of earlier measurements have been re-evaluated in order to reduce the experimental errors.…”

Levels of146Ce studied through the decay of high-spin isomer of146La

“…The isomerism in 146La was first reported by Monnand et al [10] who measured the half-lives of the low-and high-spin isomers to be 6.2 and 10.0 s, respectively. Keyser et al [ 11 ] measured the Q~-values for the two isomers of ~46La at the mass separator LOHENGRIN and reported that the high-spin isomer was the ground state of 146La, although this assignment was not confirmed by the results of later Q~-value measurements [12][13][14]. The decay of the low-spin 2-isomer of 146La with T~/2= 6.27 s has been investigated at the mass separator TRISTAN, where this isomer is predominantly produced through the /?…”