Nature(London) 554, 7691 (2018)

C.J.Chiara, J.J.Carroll, M.P.Carpenter, J.P.Greene, D.J.Hartley, R.V.F.Janssens, G.J.Lane, J.C.Marsh, D.A.Matters, M.Polasik, J.Rzadkiewicz, D.Seweryniak, S.Zhu, S.Bottoni, A.B.Hayes, S.A.Karamian

Isomer depletion as experimental evidence of nuclear excitation by electron capture

NUCLEAR REACTIONS ⁷Li(⁹⁰Zr, 3np), E=840 MeV; measured Eγ, Iγ, γγγ-coin using Gammasphere array at ATLAS-ANL. ⁹³Mo; deduced levels, first experimental evidence of process of nuclear excitation by electron capture (NEEC) through the isomer depletion of 2425-keV isomer and excitation of the 2430-keV intermediate level from the 2425-keV isomer, and observation of 2475-268-685-1478 γ cascade in coincidence.

NUCLEAR REACTIONS ⁹⁰Zr(⁷Li, 3np), E(cm)=same as above for reverse kinematic reaction; measured Eγ, Iγ, γγ-coin at Australian National Laboratory. ⁹³Mo; deduced levels, non-observation of 2475- and 268-keV γ rays in γγ coincidences in the normal kinematics reaction consistent with NEEC interpretation in the inverse kinematic reaction study at Argonne.

doi: 10.1038/nature25483