Sažetak sa skupa
Thermal neutron scattering on hydrogen atom nucleus of polyethylene
Mihailo M. Marković
; Faculty of Electrical Engineering, University of Belgrade, PO Box 816, 11001 Belgrade, Yugoslavia
Sažetak
Based on the assumptions, that the CH₂ unit is the basic unit of polyethylene affecting the thermal neutron scattering and that the phonon spectrum of polyethylene can be approximated by a discrete set of three Einstein frequencies, similar to a water molecule, a quantum mechanical expression for double differential cross section for the thermal neutron scattering on a hydrogen atom nucleus of polyethylene has been derived. For twenty-eight incident thermal neutron energies E₀∈[1 meV, 1 eV] the values of double and single differential cross sections, as well as the values of total scattering cross sections have been evaluated. The results obtained clearly show quantum inelastic effects of the creation and the destruction of polyethylene phonons, as well as highly pronounced quasielastic peaks, that occur at forward neutron scattering. The same property is also valid for inelastic scattering, but only when E₀∈[0.01 eV, 1 eV]. However, when E₀∈[0.001 eV, 0.01 eV] then the destruction of phonons of the lowest energy shows a weak dependence on a scattering angle, which vanishes quickly with the increase of thermal neutron energy.
Ključne riječi
Hrčak ID:
338941
URI
Datum izdavanja:
20.12.1989.
Posjeta: 153 *