$\alpha$-decay branching ratio of ${}^{180}\mathrm{Pt}$

A study of the ${}^{180}\mathrm{Hg}$ decay chain performed at the CERN-ISOLDE facility has allowed the ground-state–to–ground-state $\alpha$ decay of ${}^{180}\mathrm{Pt}$ to be investigated. A more precise $\alpha$-decay branching ratio of $b_{\alpha }{(}^{180}\text{Pt})=0.52\left(5\right)\%$ has been deduced. The reduced $\alpha$-decay width calculated using the new value provides a more consistent picture of the systematics for $J^{\pi }=0^{+}\to 0^{+}$ ground-state–to–ground-state state $\alpha$ decays of neutron-deficient, even-even platinum isotopes.

Figure 1

Schematic of the ${}^{180}\mathrm{Hg}$ decay chain, showing the isotopes and $\alpha$-decay energies important to the present work. The $b_{\alpha }{(}^{180}\text{Pt})=0.52\left(5\right)\%$ value is taken from the results of our study (see Sec. 3), and $E_{\alpha }{(}^{180}\text{Pt})=5160\left(5\right)$ keV is from Ref. [6]. All other data are taken from Refs. [7, 8, 9, 10, 11, 12].

Figure 2

(a) Energy spectrum of singles $\alpha$-decay events measured in Si2 at $A=180$, (b) zoomed view of the $4900–5400$-keV region, fitted with a linear background plus two Crystal Ball functions (red line), the individual contributions from the $\alpha$ decays of ${}^{172}\mathrm{Os}$ and ${}^{180}\mathrm{Pt}$ are shown by the blue lines, (c) the residual between the fit and the data shown in panel (b). The main $\alpha$-decay peaks are labeled with the corresponding isotope and $\alpha$-particle energies.

Figure 3

Reduced $\alpha$-decay widths for $J^{\pi }=0^{+}\to 0^{+}$, g.s.-to-g.s. decays of even-$A$ platinum ($•$), mercury ($▴$), and lead ($\blacksquare$) isotopes, calculated using the Rasmussen approach [2] with data taken from Refs. [8, 9, 10, 11, 12, 26, 27]. The open star is the ${\delta }_{\alpha }^2{(}^{180}\mathrm{Pt})$ calculated using the results from the present work and Ref. [6].