αdecay studies of very neutron-deficient francium and radium isotopes

Decay of201–203Raand200–202Fr

“…The α particle tentatively assigned to the decay of 202 Ra was followed by two escaped α particles. Another triple-α correlation chain was observed in the reaction 63 Cu + 141 Pr at a beam energy of (278-288) MeV yielding E α = 7740(20) keV, T 1/2 = 16 +30 −7 ms [7]. In this case the Correlation parent-daughter α1-α2energy spectrum measured in the PSSD + BOX system in the reaction 56 Fe + 149 Sm at E beam = 244 and 256 MeV.…”

“…The α-decay properties for the two 202 Ra events registered in previous experiments resulted in reduced α-decay widths of 430 +2020 −260 [18] and 44 +83 −20 keV [7]. One of them indicated a tendency of lowering δ 2 α at decreasing neutron number in radium isotopes, while the other indicated an increasing trend.…”

“…Prior to our measurement, only one ER-α1-α2-α3(escaped) decay chain originating from 201 Ra was observed in an experiment performed at RITU at JYFL [7]. The event was produced in the reaction 63 201 Ra, because the α1 decay was considered to be unhindered.…”

“…An intruder 1/2 + state was identified in 201,203 Fr using α-decay spectroscopy [7]. Isomeric 1/2 + and 13/2 + states were observed in 203 Fr [8] and 205 Fr [9] using prompt in-beam γ -ray, delayed γ -ray, and electron spectroscopy, in addition to α-decay * zdenka.kalaninova@fmph.uniba.sk studies.…”

“…Isomeric 1/2 + and 13/2 + states were observed in 203 Fr [8] and 205 Fr [9] using prompt in-beam γ -ray, delayed γ -ray, and electron spectroscopy, in addition to α-decay * zdenka.kalaninova@fmph.uniba.sk studies. Both the 1/2 + and 13/2 + states are assumed to possess oblate deformations and to coexist with the spherical 9/2 − ground state [7][8][9]. (We note that for simplicity we do not put tentative spins and parities in parentheses in the text, but we keep them in the figures.…”