3D Reconstruction of Ion-Beam Implantation Profile in Superconducting Tunnel Junctions using Atom Probe Tomography
ORAL
Abstract
Recent use of superconducting tunnel junctions (STJs) to perform precision, low-energy nuclear decay experiments from implanted radioactive ions have shown tremendous promise in our search for BSM physics. In particular, the Beryllium Electron capture in Superconducting Tunnel junction (BeEST) experiment searches for BSM neutrino-mass physics in the electron capture decay of 7Be. The search is currently limited by unexpected peak broadening, which may be due to interaction of the implanted 7Be within the STJ detector materials. In this talk, I will present the working progress for transmission electron microscopy (TEM) imaging and atom probe tomographic (APT) 3D reconstruction of 7Be and 7Li implanted into Ta-based and Al-based STJs. Such reconstructions will be compared to density functional theory modeling of the electronic structure of lithium atoms in different atomic environments of polycrystalline Ta and Al. This comparison and associated data will clarify in-medium effects to better understand the observed peak broadening towards higher sensitivity searches for new physics using STJs.
*This work is supported by the DOE-SC Office of Nuclear Physics, Lawrence Livermore National Laboratory, the Gordon and Betty Moore Foundation, and the Facility for Rare Isotope Beams. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.
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Publication: Material Effects on Electron Capture Decays in Cryogenic Sensors, A. Samanta, S. Friedrich, K. G. Leach, V. Lordi, arXiv:2206.00150
Presenters
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Cameron Harris
- Colorado School of Mines