On the decay properties of the neutron-deficient isotope 242Es

TL;DR

This study provides detailed decay properties of the neutron-deficient isotope 242Es, including half-lives, decay modes, and electron-capture delayed fission probability, with improved experimental data and comparison to theoretical models.

Contribution

The paper offers the first precise measurements of 242Es decay properties, resolving previous ambiguities and comparing experimental results with semi-empirical model predictions.

Findings

Half-life of 16.9(8) seconds for alpha decay

Electron-capture delayed fission probability of 0.015(4)

Production cross section of 27(3) nb

Abstract

The radioactive decay properties of $^{242}$Es were studied with significantly improved statistics compared to available literature data. This isotope was produced in the 3n evaporation channel of the fusion reaction of $^{48}$Ca+$^{197}$Au. A half-life of 16.9(8)~s was deduced from 662 $\alpha$ decays of $^{242}$Es, resulting in an $\alpha$-decay branching of 41(3)\%. Twenty-six fission events with a half-life of 18.2$^{+4.5}_{-3.0}$~s were assigned to originate from the electron-capture delayed fission of $^{242}$Es. The probability for the electron-capture delayed fission was measured to be 0.015(4), which improves and resolves ambiguities in available experimental data. We discuss all known cases for electron-capture delayed fission in Es, Bk, and Am isotopes and compare experimental data with predictions from a recent semi-empirical model. A cross section of 27(3)~nb was measured for the production of $^{242}$Es.