Variation with Wavelength of the Depolarisation of Polarised Neutrons by Ferromagnetic Domains

摘要

A theoretical analysis is made of neutron depolarisation by a domain structure in a ferromagnet. It is found that the depolarisation should display a damped oscillatory behaviour as the neutron wavelength is varied. It is shown that this variation of depolarisation with wavelength is related to the Fourier transform of the distribution of neutron path lengths within the domains. Measurement of this effect should allow determination of the path length distribution function, the magnetic induction B within a domain and the mean value of cos exp 2 theta where theta determines the domain orientation. It is shown that the measurements could be performed in a short time on the proposed polarisation analysis instrument on the SNS at RAL. (Atomindex citation 14:760104)