Forschungszentrum Jülich
Institut für Festkörperforschung

Inelastic Neutron Scattering from CH4 - clathrate, THF- clathrate and Ice
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H. Conrad1, W. Kuhs2, K. Nünighoff3, M. Prager4, W. Schweika1
1 Institute Scattering Methods, IFF
2 Göttinger Zentrum Geowissenschaften, Universität Göttingen
3 Institute for Nuclear Physics, FZJ
4 Institute Neutron Scattering, IFF

Inelastic neutron scattering with emphasis on energetically low lying modes has been performed on three prospective advanced cold moderator materials. Employing the time-of-flight instruments SV29 and DNS at the Jülich FRJ-2 reactor, spectra have been obtained from synthetic methane clathrate, tetrahydrofurane (THF) clathrate and light water ice at several temperatures between 2 K and 70 K. Clearly separated excitations at energy transfers of ±1 meV, +2 meV and +3 meV have been observed with synthetic methane clathrate. In hexagonal ice at T = 2 K up to now unreported low lying energy levels were found at energy transfers of 1.8 meV and 2.8 meV. An additional line at about 10 meV could be detected in the THF clathrate, which is most likely due to the embedded THF molecule.


 

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