$\ensuremath{\alpha}$-spectroscopy studies of the new nuclides $^{165}\mathrm{Pt}$ and $^{170}\mathrm{Hg}$

$α$ -spectroscopy studies of the new nuclides ${}^{165}{Pt}$ and ${}^{170}{Hg}$

J. Hilton et al.

Phys. Rev. C 100, 014305 – Published 8 July 2019

Abstract

The new nuclides ${}^{165}{Pt}$ and ${}^{170}{Hg}$ were produced in the reactions ${}^{92}{Mo} ({}^{78}{Kr}, 5 n)$ and ${}^{96}{Ru} ({}^{78}{Kr}, 4 n)$ at bombarding energies of 418 MeV and 390 MeV, respectively. For ${}^{170}{Hg}$ an $α$ -particle energy of $E_{α} = 7590 (30) keV$ and half-life of $t_{1 / 2} = 0 . 08_{- 0.04}^{+ 0.40} ms$ were deduced, while for ${}^{165}{Pt}$ the corresponding values were 7272(14) keV and $0 . 26_{- 0.09}^{+ 0.26} ms$ . Comparison of the reduced $α$ -decay widths with systematics indicates that both $α$ decays are unhindered. Although combining the measured $α$ -decay $Q$ values with extrapolated masses suggests that both new nuclides are unbound to two-proton emission by more than 1 MeV, their $α$ -decay half-lives are too short for this decay mode to compete. Improved data were also obtained for ${}^{166, 167}{Pt}$ , produced via the ${}^{96}{Ru} ({}^{78}{Kr}, α 4 n)$ and ${}^{96}{Ru} ({}^{78}{Kr}, α 3 n)$ reactions at bombarding energies of 390 MeV and 418 MeV.

Received 13 May 2019

DOI:https://doi.org/10.1103/PhysRevC.100.014305

Physics Subject Headings (PhySH)

Alpha decay Lifetimes & widths Low & intermediate energy heavy-ion reactions Nuclear structure & decays Rare & new isotopes Transfer reactions

150 ≤ A ≤ 189

Nuclear data analysis & compilation Particle sources & targets Radiation detectors Spectrometers & spectroscopic techniques

Nuclear Physics

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Vol. 100, Iss. 1 — July 2019

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Figure 1
The upper panel shows the distribution of the energies of $α$ particles occurring within 10 ms of a recoil being implanted into the same DSSD pixel plotted against the ratio of the mass number to charge state ( $A / Q$ ) of the recoil at the MWPC. The lower panel shows the $α$ -particle energy spectrum of decays occurring within 10 ms of the recoil that are followed by another $α$ particle within 50 ms versus the $A / Q$ of the recoil. The plots present the part of data set A that was used to calibrate the $A / Q$ distribution for the experiment and show that two charge states were collected for each labeled nuclide. The color scale in both panels is set such that black points represent 2–4 events, blue points 5–24 events, and yellow points $\geq 25$ events.
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Figure 2
The decay chains of the nuclides of interest. $α$ -particle energies are labeled in keV and indicated by solid arrows. Half-lives are labeled in ms, and all values are those measured in the present work. The dashed arrows denote fusion-evaporation channels used to produce ${}^{165, 166, 167}{Pt}$ and ${}^{170}{Hg}$ .
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Figure 3
Two-dimensional spectra of $α$ -particle energies of mother decays occurring within 10 ms of a recoil being implanted into the same DSSD pixel plotted against those of subsequent daughter $α$ decays occurring (a) within 50 ms from data set A, and (b) within 100 ms from data set C. Selected correlated mother $α$ decays are labeled, with newly identified nuclides highlighted in red.
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Figure 4
Energy spectra of multiple correlated full-energy $α$ decays for the decay chains of (a) ${}^{165}{Pt}$ , (b) ${}^{166}{Pt}$ , (c) ${}^{167}{Pt}$ , and (d) ${}^{170}{Hg}$ . The individual decay energies and time intervals for events in the ${}^{165}{Pt}$ chains are summarized in Table 3.
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Figure 5
The $Q$ values for (a) $α$ decay and (b) two-proton decay plotted as a function of mass number for isotopes of W, Os, Pt, and Hg [18, 19]. Values that required a predicted mass to be used in the calculation are denoted by hollow markers, whereas values that use only directly measured masses have solid markers. In (a) the error bars are smaller than the plotted symbols.
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Figure 6
Reduced $α$ -decay widths of W, Os, Pt, and Hg nuclei calculated using the method of Rasmussen [20]. (a) shows values for even- $A$ nuclei plotted as a function of neutron number, while (b) shows values for odd- $A$ nuclei. The values for ${}^{170}{Hg}$ and ${}^{165, 166, 167}{Pt}$ are denoted by the solid symbols. Literature values for the other nuclides were taken from [10, 11, 21, 29, 30, 31, 32, 33, 34, 35, 36].
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Physical Review C

covering nuclear physics

$α$ -spectroscopy studies of the new nuclides ${}^{165}{Pt}$ and ${}^{170}{Hg}$

J. Hilton et al.

Phys. Rev. C 100, 014305 – Published 8 July 2019

Abstract

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Physical Review C

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α-spectroscopy studies of the new nuclides Pt165 and Hg170

J. Hilton et al.

Phys. Rev. C 100, 014305 – Published 8 July 2019

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$α$ -spectroscopy studies of the new nuclides ${}^{165}{Pt}$ and ${}^{170}{Hg}$