Experimental beta-decay energies of very neutron-rich isobars with mass numbers A=101 and A=102

Abstract

The Q/~-values of l~ 1~176 and lo1,102y have been measured for the first time at the mass separator ISOLDE by means of/~7-coincidence techniques with a plastic scintillation detector telescope and a large Ge(HP)-detector. For some of these nuclei, also new details of their decay schemes could be derived from the measured fl-decay properties. The experimental results are discussed, as far as the systematics of two-neutron separation energies derived from them is concerned. In addition, the nuclear masses deduced from these Q,-values are compared with the predictions of recent mass calculations.

Mass measurements of neutron-rich Rb and Sr isotopes

“…6(9.8)keV. This value marks a 3σ deviation from the one adopted in AME 2012 [33,39], which is based on the result of a β-endpoint measurement [42] for 101 Sr (β − ) 101 Y. This discrepancy between β-endpoint measurements and PTMS has been documented for neutron-rich isotopes [43].…”

Discovery of rubidium, strontium, molybdenum, and rhodium isotopes

“…Balog et al published the discovery of 101 Rb in "Experimental beta-decay energies of very neutron-rich isobars with mass numbers A=101 and A=102" in 1992 [62]. "The Q β -values of 101 Rb, 101,102 Sr and 101,102 Y have been measured for the first time at a mass separator ISOLDE by means of βγ-coincidence techniques with a plastic scintillation detector telescope and a large Ge(HP)-detector."…”

Structure of the highly deformed nucleus101Sr63 and evidence for identical K=3/2 bands

“…However, the latter assignment is unlikely since these lines were not observed in our earlier study of l~176 decay [9], where 7-activities were at least two orders of magnitude stronger than in the present experiment. As a matter of fact, lines at 92, 112, 252, 271 and 363keV have already been assigned by Balog et al [21] to the/3-decay of l~ Their A = 101 7-spectra were gated by high-energy /3-rays, thus removing all activities from isobars with lower Q/~-values than l~ (11.8 MeV [21]). However, due to the large Ge-detector used in their study, neither reliable intensities for the low-energy lines were obtained, nor could the 92 keV transition be resolved as a doublet.…”

“…In particular, for the 7-lines at 92.2 and 111.6keV, which are interpreted as intraband transitions, we have assumed that their ~(E2/M1) mixing ratios are similar to those of the corresponding transitions in 99Sr [6] and l~ [17], respectively. Logft values were calculated using a Q~ value of 11.80(15) MeV [21] and a/3-decay half-life of Tv2(Rb) = 32(5) ms [20]. The level scheme of l~ as populated in the decay of lmRb is presented in Fig.…”

“…Prior to this work, the/3-decay half-life and the P,~ value of 101Rb decay were measured [20]. In addition, a few prominent "y-rays were reported following the /3-decay of l~ and were assigned to the level scheme of the I~ daughter [21]. Preliminary reports of the present work have been given in [4,22].…”