Half-lives and delayed neutron emission probabilities of short-lived Rb and Cs precursors

Abstract

Half-lives and delayed-neutron emission probabilities (P,) of short-lived Rb and Cs precursors in the mass chains 94 98 and 143 147 were measured. Sources of isotope separated nuclides were obtained from the on-line mass-separator OSTIS installed at the Grenoble high-flux reactor. A new P,-value of (25.4_+3.2)% is given for the (214_+30)ms ~TCs; the P,-values of nine alkali precursor nuclides were redetermined: (2,730_+20)ms 94Rb with (9.7_+0.

Beta-decay energies and nuclear masses of very neutron-rich Rb and Cs isotopes

“…The halflife measured for 94Rb by means of /~-, 7-and delayed-n multiscaling by several groups (cf. discussion in [20]) does not agree in all cases within the given errors, but is consistent with a mean value of 2.740 _+0.050s. There was, however, no experiment especially concerned with the search for isomerism.…”

“…5, The mean value of its halflife, calculated from the results of several measurements [20], is 377 + 6 ms. The level scheme of 95Sr was studied recently very carefully by Pfeiffer et al [22].…”

Structure in the beta strength function of very neutron-rich Rb-isotopes

“…2). The same effect was observed earlier for core-polarized states in [15,[24][25][26], the dashed lines connect values calculated by the gross theory [8], the full squares correspond to microscopic calculations the y-decay of isobaric analog states in Sc, V, Cu [22,23]. The effect is reproduced by the calculation (Fig.…”

Gamma-gamma angular correlation measurements of transitions in98Sr and98Zr and confirmation of shape coexistence in98Sr

“…A simple phenomenological coexistence model [7] gave a good discription of these lower levels of 98Sr and predictions for levels up to 900 keV. Also observed was the delayed neutron emission with a probability of (18.4_+2.9)% [8] as well as the Q~-value of (12440_+110)keV [9][10][11]. Further measurements at OSTIS [7,8] indicated the existence of two isomers of 98Rb with slightly different half-lives of (96_+8)ms and (114 _+ 13) ms, respectively.…”

“…Also observed was the delayed neutron emission with a probability of (18.4_+2.9)% [8] as well as the Q~-value of (12440_+110)keV [9][10][11]. Further measurements at OSTIS [7,8] indicated the existence of two isomers of 98Rb with slightly different half-lives of (96_+8)ms and (114 _+ 13) ms, respectively. Predictions of shape coexistence do also exist for the nucleus 98Zr [12,13].…”