Speaker
Description
The design of neutron sources, using Monte-Carlo radiation transport codes, relies on the usage of thermal scattering libraries in the ACE format. These libraries are derived from models of neutron interactions in the materials of interest. We report here on the development of such libraries for applications related to cold and very-cold neutron sources [1]. For this purpose, we have used path-integral molecular dynamics techniques [2,3] to create temperature dependent input to models for liquid hydrogen and deuterium, currently existing in modified versions of NJOY, and have extended these methods to investigate the neutron slowing down properties of new materials, for example liquid hydrogen-deuteride. Additionally, with the recent advances of the NJOY+NCrystal tool, we were able to create improved libraries for cold solid moderators, such as solid deuterium. In this work, we present an overview of these developments and some example neutronic calculations using the new libraries, related to the upcoming European Spallation Neutron Source.
[1] J.I. Marquez Damian, D.D. DiJulio, Günter Muhrer, “Nuclear data development at the European Spallation Source”, Journal of Neutron Research, vol. 23, no. 2-3, pp. 157-166 (2021)
[2] E. Guarini et al., “Velocity autocorrelation in liquid parahydrogen by quantum simulations for direct parameter-free computations of neutron cross sections”, Phys. Rev. B 92, 104303 (2015)
[3] I.R. Craig and D.E. Manolopoulos, “Quantum statistics and classical mechanics: Real time correlation functions from ring polymer molecular dynamics”, The Journal of Chemical Physics 121(8) (2004), 3368–3373