Delayed neutron emission probabilities and half-lives of Rb, Sr, Y, In, Cs, Ba and La precursors with A = 93–98, A = 127–131 and A = 142–148

Abstract

Delayed neutron emission probabilities ( P n) for 93–98Rb, 97, 98Sr, 97, 98Y, 127–131 In, 142–146Cs, 147, 148gBa and 147La were measured at the SOLIS on-line isotope separator. The P nvalues for 97, 98Sr, 97, 98Y, 147, 148Ba and 147La were measured for the first time. Delayed neutron emission is energetically unfavourable for 147Ba and 148Ba precursors, according to predictions of at least four of the most common mass formulas, however, respective P n values of (5.21 ±0.52) % and (23.9 ± 2.1 )% were determined. The P n values were determined by counting β and neutron activities simultaneously. The energy dependence of the counting system was ∼ 3 % for the relevant delayed neutron spectra range, i.e., 0–1.5 MeV. Half-lives for all precursors were measured from both β and neutron decay curves.