Molecular contributions to the thermal neutron cross sections of O2, N2, and air
Abstract
We provide an updated scattering library for the simulation of thermal neutron transport in air, including the effects of rotational and vibrational modes in N2 and O2 and neutron magnetic scattering in O2, showing their significance compared to smaller effects related to water humidity. The modeling is based on the Young–Koppel treatment of thermal neutron scattering from diatomic molecules, as well as ab initio simulations of the electronic density of O2. The theoretical predictions are benchmarked against experimental measurements of the total scattering cross section of air under monitored thermophysical conditions, in the neutron energy range between 0.6 meV and 10 keV. The updated scattering library is used to calculate excess neutron scattering in air, compared to traditional approaches, where only nuclear scattering from gases of free nuclei is implemented in Monte Carlo transport codes.
Article Details
Journal Info
The Journal of Chemical Physics
American Institute of Physics
Authors (11)
Margherita Simoni
Physics Department, Università degli Studi di Roma Tor Vergata 1 , via della Ricerca Scientifica 1, 00133 Roma,
Felix Fernandez-Alonso
Centro de Física de Materiales (CFM-MPC), CSIC-UPV/EHU 2 , Paseo de Manuel Lardizabal 5, Donostia 20018, Gipuzkoa,
Tommaso Giovannini
Department of Physics, University of Rome Tor Vergata and INFN 6 , Via della Ricerca Scientifica 1, 00133 Rome,
Matthew Krzystyniak
Jose Ignacio Marquez Damian
European Spallation Source, ESS ERIC 6 , Partikelgatan 2, 224 84 Lund,
Anna Marsicano
ISIS Neutron and Muon Source, Rutherford Appleton Laboratory 5 , Chilton OX11 0QX,
Marco Martellucci
Physics Department, Università degli Studi di Roma Tor Vergata 1 , via della Ricerca Scientifica 1, 00133 Roma,
Triestino Minniti
Physics Department, Università degli Studi di Roma Tor Vergata 1 , via della Ricerca Scientifica 1, 00133 Roma,
Roberto Senesi
Physics Department, Università degli Studi di Roma Tor Vergata 1 , via della Ricerca Scientifica 1, 00133 Roma,
Matteo Sorbara
Physics Department, Università degli Studi di Roma Tor Vergata 1 , via della Ricerca Scientifica 1, 00133 Roma,
Giovanni Romanelli
Physics Department, Università degli Studi di Roma Tor Vergata 1 , via della Ricerca Scientifica 1, 00133 Roma,