A system was developed for producing repetitive short bursts of preferentially oriented spin polarized neutrons for magnetic investigations utilizing neutron spectroscopy. A continuous stream of polarized neutrons from a reactor‐monochromator combination is passed through a region in which periodic inversion of polarization is effected by continuous application of an rf field at the Larmor frequency perpendicular to a pulse modulated dc magnetic field. A novel circuit for fast transition modulation of the dc field permits currents as high as 1 A to be switched in less than 2 &mgr;sec in the 6 mH dc coil. The maximum burst repetition rate is approximately 83 300 pulses/sec.