Developments in neutron Fourier time-of-flight

Two main developments in neutron Fourier time-of-flight (TOF) are presented. The first is a new sinusoidal stator design that eliminates a systematic effect associated with triangular modulation in existing Fourier choppers. Despite sinusoidal modulation being associated with a reduction in average beam transmission, it is mathematically demonstrated that, on average and for good signal-to-background, only about 3 % additional measurement time is required to achieve equal statistical uncertainty. The second development is a new method to measure the chopper phase offset. This method relies only on symmetries inherent to the Fourier transform of any physical TOF spectrum.