Low-lying states in Ra219 and Rn215 : Sampling microsecond α -decaying nuclei

Abstract

Short-lived α-decaying nuclei 'North-East' of 208 Pb in the chart of nuclides were studied using the reaction 48 Ca + 243 Am with the decay station TASISpec at TASCA, GSI Darmstadt. Decay energies and times from pileup events were extracted with a tailor-made pulse shape analysis routine and specific α-decay chains were identified in a correlation analysis. Decay chains starting with the even-even 220 Ra and its odd-A neighbors, 219 Fr, and 221,219 Ra, with a focus on the 219 Ra→ 215 Rn decay, were studied by means of α-γ spectroscopy. A revised α-decay scheme of 219 Ra is proposed, including a new decay branch from a previously not considered isomeric state at 17 keV excitation energy. Conclusions on nuclear structure are drawn from the experimental data, aided by Geant4 simulations and a discussion on theoretical calculations.

Fusion reaction Ca48+Bk249 leading to formation of the element Ts ( Z=117Khuyagbaatar1, Yakushev2, Düllmann3 et al. 2019Phys. Rev. CSelf Cite321170View full textAdd to dashboardCite

“…Advantages of CANDI for the solution of various physics and measurement technical issues have been demonstrated in Refs. [12,37,[43][44][45][46].…”

Search for elements 119 and 120

“…In fact, in almost every 48 Ca +actinide reaction, ERs were observed at projectile energies up to 10 MeV above the fusion barrier (V B ) [57], i.e., (1.00-1.07)V B [1,58,59]. These energies then correspond to E * in the range of [35][36][37][38][39][40][41][42][43][44][45] MeV. This shows that E * within this range does not drastically affect the final results of these 064602-5 fusion-evaporation reactions, i.e., the σ ER .…”

“…The advantages of CANDI-type systems for the solution of various physics and measurement technical issues and for superheavy element search experiments are demonstrated in Refs. [11][12][13]16,41,[43][44][45][46].…”

The half-life of $^{212}$Po

“…It should also be noted that the half-life of 212 Po was measured in Refs. [19,20,21,22,23,24,25] as a by-product of the BiPo sub-chain analysis for different purposes (estimation of low-counting detectors' internal con-tamination by thorium, calibration of detectors, study of low-lying states in α-decaying nuclei). Typically the results are affected by large statistical uncertainties up to 17% 2 , and the systematic effects were not evaluated.…”