Max Planck Institute, Heidelberg refutes NEEC(electron capture) theory
of Molybdenum 193 isomer 'decay'.
Experimental results by Chiara(US Army ) et al ,2018 are
approximately nine orders of magnitude too large
compared to NEEC prediction.
May be relevant to P. Hagelsteins' Co57/Fe57 m 2018 findings
and J. Wyttenbach NPP2 2018 theory.
93mMo isomer depletion via beam-based nuclear excitation by electron capture
Yuanbin Wu,∗ Christoph H. Keitel, and Adriana P´alffy†
Max-Planck-Institut f¨ur Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
(Dated: June 3, 2019)
A recent nuclear physics experiment [C. J. Chiara et al., Nature (London) 554, 216 (2018)] 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 excitation energy were slowed down in a solid-state target. In this process, nuclear excitation to a higher triggering level led to isomer depletion. The reported excitation probability Pexc = 0.01 was solely attributed to the so-far unobserved process of NEEC in lack of a different known channel of comparable efficiency.
In this work, we investigate the beam-based setup and calculate excitation rates via NEEC using state-of-the-art atomic structure and ion stopping power models.
For all scenarios, our results disagree with theexperimental data by approximately nine orders of magnitude.
This stands in conflict with the conclusion that NEEC was the excitation mechanism behind the observed depletion rate.