Publications
Showing 62 results for Author: Erik B. Iverson
Aug, 2026
Conference Paper
Improved Moderator Performance Calculations at SNS
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory reached a nominal operating power of 1 MW in September, 2009. Even at ~2/3 of its designed capacity, SNS already becomes the brightest pulsed neutron source in the world, and a premier facility for material and life science research. To provide accurate target performance estimation and to meet future dev…
Jul, 2026
Conference Paper
Overview of MARS: The Multimodal Advanced Radiography Station at the High-Flux Isotope Reactor
Neutron imaging is a powerful tool used for inspecting internal structures and studying macroscale particle dynamics. This work is performed at the Multimodal Advanced Radiography Station (MARS), which is the cold-neutron imaging beamline at the High-Flux Isotope Reactor at Oak Ridge National Laboratory. Herein is a summary of recent upgrades to instrumentation, software,…
Mar, 2026
Conference Paper
Design of the cryogenic moderator system for the second target station
The Second Target Station (STS) at Oak Ridge National Laboratory will be a 700 kW pulsed spallation neutron source designed to provide the world's highest brightness cold neutron beams. In order to produce the required neutron performance, two compact liquid hydrogen moderators are located adjacent to the tungsten spallation target and must be supplied with less than 20 K…
Mar, 2026
Journal
First full Dalitz plot measurement in neutron 𝛽 decay using the Nab spectrometer and implications for new physics
Precision measurements of observables in neutron 𝛽 decay are used to test the standard model description of the weak interaction and search for evidence of new physics. The Nab experiment at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source was constructed to measure correlations in neutron decay by utilizing an asymmetric spectrometer and novel det…
Mar, 2026
ORNL Report
Spectral Flux Measurements on SNS Direct Geometry Spectrometers at IRP-2 End-of-Life
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…
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…