München 2019 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 50: Structure and Dynamics of Nuclei X
HK 50.4: Talk
Thursday, March 21, 2019, 15:00–15:15, HS 16
Nuclear excitation by electron capture in a beam-target scenario — •Yuanbin Wu and Adriana Pálffy — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
A recent nuclear physics experiment [1] reports the first direct observation of nuclear excitation by electron capture (NEEC) in the depletion of the 93mMo isomer. The experiment used a beam-based setup in which Mo highly charged ions with nuclei in the isomeric state 93mMo at 2.4 MeV are slowed down in a solid-state target and electron recombination can excite the nucleus to produce isomer depletion via a triggering level lying 4.85 keV above the isomer. The reported excitation (and subsequent depletion) probability Pexc = 0.01 was attributed to the so-far unobserved process of NEEC.
In this work, we investigate theoretically the beam-based setup and calculate isomer depletion rates based on state-of-the-art NEEC cross sections [2] and different ion stopping power models. For all scenarios, our calculated NEEC probability is several orders of magnitude smaller than the measured Pexc. This large discrepancy suggests that the observed isomer depletion has a different underlying nuclear excitation mechanism than NEEC.
[1] C. J. Chiara, J. J. Carroll, M. P. Carpenter, et al., Nature 554, 216 (2018).
[2] Y. Wu, J. Gunst, C.H. Keitel, and A. Pálffy, Phys. Rev. Lett. 120, 052504 (2018).