• 25 February 2026
  • 3:30 EST
 Data Science and Engineering for Nuclear Nonproliferation Modern data science has the potential to significantly advance capabilities across the nuclear nonproliferation landscape. However, many popular and commercially successful supervised machine learning applications to image analysis and natural language processing require large amounts of carefully curated training data. The ubiquity of rare events embedded in massive datasets limits the applicability of these solutions to many national security problems and instead necessitates the development of novel data analytic methodologies. This seminar will provide an overview of nuclear nonproliferation research at Oak Ridge National Laboratory, including several research projects developing robust data analytic techniques for nonproliferation relevant data modalities. A semi-supervised machine learning approach using physics-informed, label-invariant data augmentations for training embedding models to process gamma radiation spectra will be presented. These embedding models are used to analyze sensor data and characterize shielded radiological material transfers. A method for incorporating subject-matter expertise in machine learning models for sparse data analytics will also be presented. Knowledge injection allows practitioners to define salient, human-interpretable concepts that can improve few-shot models and provides a method for evaluating the sensitivity of models to mission knowledge. These approaches address high consequence challenges in data interpretation and support the nuclear nonproliferation mission.
  • 27 February 2026
  • 2:00 EST
 Actinide Abundances, Variation, and Evolution in Metal-Poor Stars The actinides, including thorium (Th), are the heaviest observable elements synthesized in the universe, holding clues to the extremes of the astrophysical and nuclear conditions of r-process sites. I present Th abundances based on high-resolution spectroscopy for 47 metal-poor stars, the largest homogeneously analyzed sample to date. The chemical evolution of Th exhibits a decrease in dispersion in [Th/H] and [Th/Fe], from 0.6 dex at the lowest metallicities to 0.25 dex at higher metallicities. I will discuss how Th closely tracks lanthanides Eu and Dy across metallicities of -3.0 ≲ [Fe/H] ≲ -1.5, as well as across r-process enrichment levels of 0.0 ≲ [Eu/Fe] ≲ 2.5. While the absolute range of logε(Th/Eu) is 1.02 dex, the average intrinsic scatter of the ratio is only ±0.10 dex. This implies that 68% of r-process events have actinide-to-lanthanide yields that vary within a factor of only ±1.26 or ±26%, while 5% of r-process events have yields that vary by a factor of ≳ 2.5, approaching ~10. I will discuss how this result serves as a strong constraint for nuclear and astrophysical models, as well as implications for r-process sites.
  • 27 February 2026
  • 3:00 EST
 APS upgrade: Commissioning the world’s first light source based on swap-out injection The Advanced Photon Source (APS) recently completed a transformative upgrade, replacing its 25-year-old storage ring with a state-of-the-art hybrid seven-bend achromat lattice with six additional reverse bends. The new design features a low natural emittance of 42 pm-rad, enabling production of X-rays up to 500 times brighter than the original APS. The upgrade introduced a pioneering swap-out injection scheme, replacing entire depleted bunches rather than topping them up. This approach enables on-axis injection to accommodate the reduced dynamic aperture resulting from strong focusing. This talk describes the commissioning process, reviews operating experience with swap-out injection, and gives performance parameters of new systems such as the bunch-lengthening cavity.
  • 3 March 2026
  • 11:00 EST
 A Path to Predictive Power: Tracing Nuclear Structure to Fundamental Interactions USAThe nuclear many-body problem can be formulated in terms of nucleonic correlation functions (CFs), or propagators, using as sole input the interaction between nucleons defined in the vacuum. In this framework, nuclear structure emerges from the dynamical dressing of fermionic degrees of freedom by many-body correlations. I will focus on the quantification of the two-nucleon CFs within an equation-of-motion approach beginning from a formally exact theory. Of particular relevance for strongly correlated systems is (i) the decoupling of low-rank propagators from the higher-order hierarchy through cluster decomposition, combined with (ii) the explicit retention of their mutual dynamical coupling. This strategy isolates the leading effects of emergent collectivity and establishes an in-medium power counting scheme that guides systematic non-perturbative refinements of the description in a parameter-free manner. The latter naturally provides a framework for uncertainty quantification of dynamical nuclear structure observables at intermediate to strong coupling. Recent results for the structure and response of medium-mass and heavy nuclei within this framework will be presented. Current implementations allow us to employ both effective and bare meson–nucleon Lagrangians, yielding a finite in-medium theory. Applications to electromagnetic and weak response indicate that increasing configuration complexity progressively improves the spectroscopic quality of the description over wide energy intervals. These developments suggest a viable path toward shell-model-level accuracy — and potentially beyond — in large model spaces within a covariant and systematically extensible framework transferable across energy scales.
  • 13 March 2026
  • 3:00 EDT
 From Reliability to Innovation: The LANSCE Modernization Roadmap
  • 18 March 2026
  • 5:30 EDT
 Conversation: Music, Science, and Video Games Join us for an engaging discussion that explores the intersections of music, science, and video games. Featuring composer and techno innovator Carl Craig, physicist Pablo Giuliani from the Facility for Rare Isotope Beams (FRIB), game developer Ryan Thompson, and musician/producer Chris Vrenna (University of Michigan, Nine Inch Nails), this conversation dives into creativity, technology, and interactive media. Moderator Amanda Cote guides the panel through how sound, science, and play inform artistic and experiential practice. Register here: https://113145.blackbaudhosting.com/113145/Conversation-Music-Science-and-Video-GamesUniversity Museum https://113145.blackbaudhosting.com/113145/Conversation-Music-Science-and-Video…