Length and Time Scales Measured Using Neutron and X-ray Scattering | NNSS 2025

Length and Time Scales Measured Using Neutron and X-ray Scattering Presented by Roger Pynn 1st National Neutron Scattering School, 2025 Oak Ridge National Laboratory (ORNL) In this lecture, Roger Pynn explores the range of length and time scales accessible through neutron and x-ray scattering techniques. The presentation explains how experimental geometry, wavelength, and energy resolution determine the spatial and temporal windows that can be probed in materials research. Pynn outlines the relationship between momentum transfer and real-space length scales, showing how small-angle scattering, diffraction, and reflectometry access structures from atomic distances to mesoscale features. The lecture also discusses how energy resolution governs sensitivity to dynamic processes, linking spectroscopic methods to characteristic timescales of atomic motion, diffusion, and collective excitations. By connecting scattering observables to measurable length and time regimes, the session provides a unifying framework for understanding when to use different techniques and instruments. The presentation emphasizes how thoughtful selection of probe, configuration, and resolution allows researchers to target specific structural and dynamical phenomena across a wide spectrum of materials systems. Learn more about neutron science at ORNL: https://neutrons.ornl.gov Learn about the National Neutron Scattering School at ORNL: https://neutrons.ornl.gov/nns