Abstract
In this work we present NJOY+NCrystal, a tool to generate thermal neutron scattering libraries with support for coherent and incoherent elastic components for crystalline solid materials. This tool, which is a customized version of NJOY, was created by modifying the nuclear data processing program NJOY to call the thermal scattering software library NCrystal, and includes a proposed change in the ENDF-6 format to store both the coherent and incoherent elastic components. Necessary changes to enable this format in NJOY, as well as to sample it in the OpenMC Monte Carlo code, are detailed here. Examples of materials that are coherent–dominant, incoherent–dominant, and mixed elastic scatterers are presented, as well as the creation of novel libraries for MgH2 and MgD2, that are under consideration as advanced neutron reflectors in the HighNESS project at the European Spallation Source. NJOY+NCrystal greatly simplifies the process to generate thermal scattering libraries (TSL) and this is exemplified with 213 new and updated TSL evaluations.
Highlights
The European Spallation Source, which is under construction in Lund, Sweden, will be the most powerful neutron source in the world
In this work we presented a new tool for creating thermal neutron scattering libraries for crystalline solid materials that combines the strengths of the industry standard NJOY2016 with the new capabilities of the software library NCrystal
This new tool includes the implementation of the new mixed elastic format for evaluated nuclear data files (ENDF)-6 files, as well as a proposal for mixed elastic support in the .ACE format
Summary
The European Spallation Source, which is under construction in Lund, Sweden, will be the most powerful neutron source in the world. In ENDF format, File 7 stores the thermal neutron scattering data in two sections: one for elastic and one for inelastic scattering. LEAPR has a limited support for coherent elastic scattering physics through few hard-coded materials (seen in Table 1), the inelastic component can be only calculated in the incoherent approximation, and it is limited by the physics that can be stored in ENDF format. The NCrystal library [9, 10] has an extensive treatment of the calculation of thermal neutron scattering cross sections directly but cannot generate ENDF-6 formatted files. With NJOY+NCrystal, the user isn’t anymore limited to materials with hard-coded options, but any solid poly-crystalline material can be calculated with support for coherent and incoherent elastic components in the current ENDF format, as well as in the proposed mixed elastic format. The Monte Carlo code OpenMC [4] was modified as well to support this new format of .ACE files, which makes this a complete implementation, starting from microscopic calculations and ending with Monte Carlo sampling
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
