It was suggested [Nunes, Nathans&Schoenborn (1971).Acta Cryst. A27, 284–291] that collection of neutron diffraction data from protein crystals could be accelerated greatly by a white‐beam Laue technique (to make full use of the reactor spectrum) with Fourier time‐of‐flight analysis employed to obtain individual reflection intensities. A prototype Fourier chopper has been built. In this paper are described its construction, operation, methods of data analysis, and tests performed with a myoglobin crystal. Although the technique is proved feasible, it is of marginal value when used with a single detector. A spectrometer utilizing an extended detector array is required to realise its full po