International Conference on Nuclear Data for Science and Technology 2010
J. Korean Phys. Soc. 59, 1076-1079
Paper ID: ND-1096
DOI: 10.3938/jkps.59.1076
PACS: 25.40.Dn, 25.40.Fq, 28.20.Cz
Neutron Cross Sections Libraries for Methane in Phase II and Solid Deuterium
J. R. Granada1,2, F. Cantargi1 and J. I. Márquez Damián1,2
1 Comisión Nacional de Energía Atómica, 8400 S.C. de Bariloche (RN), Argentina
2 CONICET, Argentina
We present new cross section libraries for two materials of interest as very cold and ultra cold neutron moderators: solid Methane in phase II and solid Deuterium. A simple model to describe the interaction of slow neutrons with solid methane in phase II (T<20.4K) was developed, including the main dynamical features of the system and the effect of spin correlations. Its predictions are in good agreement with a quantum mechanical calculation over the limited range where the latter was formulated, and with available experimental information over the complete thermal energy range. Also, we introduce cross section libraries based on a new scattering kernel recently developed to describe the interaction of slow neutrons with solid Deuterium (T<18.7K). The main characteristics of that system are contained in the model, including the lattice’s density of states, the Young-Koppel quantum treatment of the rotations, and the internal molecular vibrations. The elastic processes involving coherent and incoherent contributions are fully described, as well as the spin-correlation effects. The results from the new model are compared with the best available experimental data, showing very good agreement.
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