Neutron Diffraction Utilizing the T-O-F Method

Abstract

Characteristic features of the TOF (time of flight) neutron diffraction are summarized. In this method, i) all the reciproal points on the rod passing through the origin in the reciprocal space can be scanned by each burst of white neutrons, ii) it is easy to measure high index reflections at the large scattering angle, iii) each reflection is not affected by the higher-order harmonics, and iv) it is easy to measure the physical properties depending on the neutron wavelength.The pulse neutron generator as well as the data acquisition system in the Laboratory of Naclear Science of Tohoku University is described.The TOF method seems to be very powerful if it is applied to the accurate structure analysis. The data correction methods are discussed. The TOF method is prospective to the study of transient phenomena. In this method one can apply to the crystalline sample an external field pulsed with the same frequency as the neutrons. By using this method, the transient state of the polarization reversal of the ferroelectric NaNO2 has been observed.The magnetically pulsed neutron TOF spectrometer is briefly introduced after a review of the choper history.