Mar, 2026
Conference Paper
Publications
Showing 26 results for Author: Kyle B. Grammer
Mar, 2026
Conference Paper
Neutronics Study of HTR-10: Impact of Graphite Porosity Representation in ENDF/B-VIII.1 TSLs
Nov, 2025
Journal
The total neutron cross section of liquid and solid ammonia
Ammonia is a material of interest for future neutron moderators at high-power sources due to its high hydrogen density, low melting point, and resistance to polymerization in an intense radiation field. Its performance in such applications cannot currently be calculated due to the absence of suitable computer models for the interaction of neutrons with ammonia under releva…
Oct, 2025
Journal
Updating the MCNP neutron guide extension for supermirror absorption, gamma production, and neutron polarization
As supermirror technology has developed, there is a trend towards higher m-values for supermirrors which propagate more neutrons with higher divergence to experimental areas. These supermirrors have thousands of alternating layers of typically nickel and titanium with varying thicknesses deposited on the surface. Neutrons of grazing incidence are reflected from these layer…
Oct, 2025
Journal
An NCrystal extension for thermal neutron scattering in MCNP
A new extension for MCNP has been developed that incorporates the NCrystal thermal scattering package in the form of a Fortran to C++ wrapper, which adds the capability to describe thermal neutron scattering in the NCrystal formalism instead of the ACE tabular format. This can be used to described poly- or single-crystalline materials as well as liquids. The functionality…
Jul, 2025
Journal
Porosity in nuclear graphite and its impact on nuclear reactor science and criticality safety applications
Porosity in nuclear-grade graphite significantly influences its low-energy neutron scattering, yet its effect on underlying phonon properties remains debated. This work integrates inelastic and small-angle neutron scattering (INS/SANS) experiments, advanced atomistic simulations with a novel machine-learned potential (DeepMD), total cross-section measurements, and neutroni…
Jun, 2025
Journal
First Observation of P-odd gamma-Physical Asymmetry in Polarized Neutron Capture on Hydrogen
We report the first observation of the parity-violating 2.2 MeV gamma-ray asymmetry A^(np)_gamma in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. A^(np)_gamma isolates the Delta I = 1, ^3S_1-> ^3P_1 component of the weak nucleon-nucleon interaction, which is…
Dec, 2024
Conference Paper
Conceptual Design of the Moderator Test Station at the Spallation Neutron Source
We describe the Moderator Test Station (MTS), under construction at the Spallation Neutron Source. We will leverage the Beam Test Facility (BTF) at the Spallation Neutron Source to provide a moderator neutronics test stand with which we will verify the anticipated performance gains expected and required from the innovative moderator concepts central to the SNS Second Targe…