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Expanding the Search for Evidence of Nuclear Excitation by Electron Capture to New Nuclear/Atomic Systems

ORAL

Abstract

Nuclear excitation by electron capture (NEEC) is a coupled nuclear/atomic process by which the energy released during the capture of an electron into an atomic vacancy excites the nucleus of the atom to a higher-energy state. This phenomenon was proposed theoretically over 40 years ago [1], but the first experimental evidence was not forthcoming until much more recently [2,3], for the nucleus $^{93}$Mo. To expand our knowledge of NEEC beyond this single case, we performed an experiment similar to the successful one for $^{93}$Mo [2] to search for evidence of NEEC in the nucleus $^{127}$Cs. The T$_{1/2} \quad =$ 55-$\mu $s isomer in $^{127}$Cs was populated via the $^{9}$Be($^{123}$Sb, 5n) reaction; this isomer is a candidate for NEEC, with excitation possible to a level lying about 2 keV higher in energy. Considerations that went into the design of the experiment, and its subsequent implementation, will be discussed. \newline \newline [1] V. I. Goldanskii and V. A. Namiot, Phys. Lett. B \textbf{62}, 393 (1976). \newline [2] C. J. Chiara et al., Nature \textbf{554}, 216 (2018). \newline [3] C. J. Chiara et al., Nature \textbf{594}, E3 (2021).

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Authors

  • C. J. Chiara

    DEVCOM Army Research Lab

  • Blakesley Burkhart

    Massachusetts Institute of Technology, None, University of Colorado Boulder, Virginia Tech, MIT Haystack Observatory, University of Alabama, Johns Hopkins University, University of Maryland College Park, University of Illinois Urbana Champaign, Rutgers University, Institute of Solar-Terrestrial Physics, New Jersey Inst of Tech, Flatiron Institute, Rutgers, The State University of New Jersey, University of KwaZulu-Natal, Los Alamos National Laboratory, The College of William \& Mary, Cornell University, Cornell University, California Institute of Technology, California Institute of Technology, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), New Jersey Institute of Technology, New Jersey Institute of Tech, University of Applied Sciences and Arts Northwestern Switzerland, Princeton University, University of Pittsburgh, DEVCOM Army Research Lab, University of Louisville, University of Cape Town, Rutgers University/Flatiron Institute, Center for Astrophysics, Harvard & Smithsonian, Research School of Astronomy and Astrophysics, The Australian National University, Rutgers, the State University of New Jersey