research papers
With a double-axis spectrometer the neutron-scattering cross section dσ/dΩ of polycrystalline graphite has been measured as a function of temperature. The elastic coherent scattering yielded the variations of the lattice constants for the directions parallel and perpendicular to the c axis of the hexagonal graphite lattice. For these lattice directions also the Debye–Waller factors have been determined and from them the mean-square vibration amplitudes of the atoms and the effective Debye temperatures have been calculated.