Decay of 92.5-MinLa142

Abstract

The decay properties of 92.5-min ${\mathrm{La}}^{142}$ have been studied using scintillation spectrometric techniques. The energies, intensities, and time-correlations of the associated beta and gamma transitions have been investigated. The gamma-ray energies (and relative intensities) observed are: 0.645 (1.000), 0.86 (0.05), 0.898 (0.185), 1.01 (0.094), 1.06 (0.077), 1.16 (0.059), 1.25 (0.057), 1.37 (0.050), 1.55 (0.053, 0.044), 1.74 (0.106), 1.91 (0.176), 2.06 (0.132), 2.14 (0.044), 2.19 (0.099), 2.41 (0.314), 2.55 (0.227), 2.67 (0.061), 2.80 (0.046), 2.99 (0.11), 3.14 (0.021), 3.31 (0.039), 3.45 (0.026), 3.65 (0.048) MeV. The beta-ray groups (and approximate branching ratios) are 4.49 (13%), 3.85 (2%), 2.98 (2%), 2.31 (7%), 2.11 (24%), 1.98 (20%), 1.79 (11%), 1.23 (5%), 0.87 (13%) MeV. On the basis of these results, a decay-scheme has been constructed with excited states in ${\mathrm{Ce}}^{142}$ at 0.645, 1.54, 1.66, 2.02, 2.19, 2.41, 2.55, 2.71, 3.31, 3.45 and 3.65 MeV. The ${\mathrm{Q}}_{\beta }$ value for the ${\mathrm{La}}^{142}$-${\mathrm{Ce}}^{142}$ decay was found to be 4.51±0.03 MeV.