 The closest approach to this resolution by a spectroscopic neutron instrument type, namely the 
backscattering spectrometer (BSS), is in the range of 0.5 to 1 μeV.The spin-echo trick allows to use an intense beam of neutrons with a wavelength distribution of 10% or more and at the same time to be
sensitive to velocity changes in the range of less than 10−4.Note