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Free keywords:
Nuclear data analysis & compilation, Spectrometers & spectroscopic techniques, 59 ≤ A ≤ 89, Collective levels, Electromagnetic transitions, Giant resonances, Isomer decays, Lifetimes & widths, Neutron skin thickness, Nuclear astrophysics, Nuclear decay, Nuclear many-body theory, Nuclear shapes and moments, Nuclear structure & decays, Nuclear transition rates, Shell model
MPINP:
Präzisionsexperimente - Abteilung Blaum
Abstract:
The nuclear two-photon or double-gamma (2y) decay is a second-order electromagnetic process whereby a nucleus in an excited state emits two gamma rays simultaneously. To be able to directly measure the 2y decay rate in the low-energy regime below the electron-positron pair-creation threshold, we combined the isochronous mode of a storage ring with Schottky resonant cavities. The newly developed technique can be applied to isomers with excitation energies down to ∼100 keV and half-lives as short as ∼10 ms. The half-life for the 2y decay of the first-excited 0+ state in bare 72Ge ions was determined to be 23.9(6) ms, which strongly deviates from expectations.
