0000000000115444
AUTHOR
P.g. Thirolf
"Safe" Coulomb excitation of 30Mg.
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient $\gamma$ -spectrometer MINIBALL. Using $^{30}$Mg ions accelerated to an energy of 2.25MeV/u together with a thin $^{nat}$Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative de-excitation $\gamma$ -ray yields the B(E2; 0$^{+}_{gs} \rightarrow 2^{+}_{1}$) value of $^{30}$Mg was determined to be 241(31)$e^{2}$fm$^{4}$. Our result is lower than values obtained at projectile fragmenttion facilities using the intermediate-ene…
Direct detection of the elusive 229thorium isomer: Milestone towards a nuclear clock
Recently, the first direct detection of the long-searched low-lying isomeric first excited state of 229Th could be realized via its internal conversion decay branch, which confirms the isomer's existence and lays the foundation for precise studies of its decay parameters, in particular its half-life and excitation energy. Follow-up studies confirmed the theoretically expected lifetime reduction by about 109 of neutral 229mTh compared to charged isomers with τ∼10 μS thus emphasizing the need to efficiently suppress internal conversion when aiming for the detection of a potential photonic decay branch of 229mTh. Work towards precisely determining the excitation energy of the thorium isomer is…