Thermal Neutron Cross Sections of Cold-Moderators

This paper reviews some moderators for cold neutron source. As a good cold moderator, solid methane was studied and evaluated using the new synthetic frequency spectrum theory (SFS). Due to its high proton density and easy handling, mesitylene (not included in ENDF/B) has also been considered as a very good moderator for cold neutron source. Evaluation of this material in different crystalline phases was done by using a preliminary frequency spectra built combining experimental and synthetic contributions. As a result, we have generated ACE format scattering data files by the NJOY code, with validations of comparing total cross sections from experiments.