New neutron-deficient isotopes from $^{78}$Kr fragmentation

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, the fragmentation of a $^{78}$Kr beam allowed the observation of new neutron-deficient isotopes at the proton drip-line. Clean identification spectra could be produced and $^{63}$Se, $^{67}$Kr, and $^{68}$Kr were identified for the first time. In addition, $^{59}$Ge was also observed. Three of these isotopes, $^{59}$Ge, $^{63}$Se, and $^{67}$Kr, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes $^{58}$Ge, $^{62}$Se, and $^{66}$Kr were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic…

Studying the Exotic Decay $^{70}Kr$ $\rightarrow$ $^{70}Br$

Acta physica Polonica / B 51(3), 587 (2020). doi:10.5506/APhysPolB.51.587

Super-Allowed β Decay of23Mg Studied with a High-Precision Germanium Detector

Precise measurements of half-lives and branching ratios for the ββ mirror transitions in the decay of 23Mg and 27Si

Half-lives and branching ratios for the two mirror ββ decays of 23Mg and 27Si have been measured at the University of Jyväskylä with the IGISOL facility. The results obtained, T1/2=11.303(3)T1/2=11.303(3) s and T1/2=4.112(2)T1/2=4.112(2) s for the half-lives of 23Mg and 27Si , respectively, are 7 and 8 times more precise than the averages of previous measurements. The values obtained for the super-allowed branching ratios of 23Mg and 27Si are B.R.=92.18(8)%B.R.=92.18(8)% and B.R.=99.74(2)%B.R.=99.74(2)% , respectively. The result for 23Mg is three times more precise than the average of the previous measurements, while for 27Si the precision has not been improved, the average of the previous…

Half-life, branching-ratio, andQ-value measurement for the superallowed0+→0+β+emitterTi42

The half-life, the branching ratio, and the decay $Q$ value of the superallowed $\ensuremath{\beta}$ emitter $^{42}\mathrm{Ti}$ were measured in an experiment performed at the JYFLTRAP facility of the Accelerator Laboratory of the University of Jyv\"askyl\"a. $^{42}\mathrm{Ti}$ is the heaviest ${T}_{z}=\ensuremath{-}1$ nucleus for which high-precision measurements of these quantities have been tried. The half-life (${T}_{1/2}=208.14\ifmmode\pm\else\textpm\fi{}0.45$ ms) and the $Q$ value [${Q}_{\mathrm{EC}}=7016.83(25)$ keV] are close to or reach the required precision of about 0.1%. The branching ratio for the superallowed decay branch [$\mathrm{BR}=47.7(12)%$], a by-product of the half-lif…

Two-Proton Radioactivity ofKr67

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from 67Kr. At the same time, no evidence for 2p emission of 59Ge and 63Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to 67Kr as being the best new candidate among the three for two-proton radioactivity. 67Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of 67Kr is 7.4(30) ms.