Measurement of total cross-section and spin conversion in solid methane

✍ Scribed by H Friedrich; S Grieger; K Guckelsberger; R Scherm; W Press

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 166 KB
• Volume: 226
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(96)00307-9

✦ Synopsis

We report on transmission experiments with solid methane, where the total scattering cross-section atot(E,, T) was measured for incident neutron energies 0.5 ~< En ~< 20 meV and temperatures 0.3 ~< T ~< 15 K. Two aspects are important: (a) Different theoretical calculations of the cross-section only agree in the limit E n ---, 0. Our TOF measurements confirm one of the models and show that the cross-section may be considerably lower than the incoherent limit of 4 bound independent protons. (b) Spin conversion measurements were carried out after sudden changes of the lattice temperature. Time constants were found in the range of 0.1-800 h.