Bunching of continuous neutron beams

We present a system which can shape the intensity of a continuous, polychromatic polarized neutron beam into a high frequency sinusoidal signal of high contrast. It is based on a pure quantum-mechanical effect (longitudinal Stern–Gerlach). The system relies on a sequence of three RF flippers, and it works virtually loss-free. The signal occurs far downstream of the last flipper within a well defined region. As an application we discuss its use in high resolution neutron spectroscopy.