[en] An extremely compact line-geometry pulsed source of photoneutrons is proposed with controllable energies of only a few kiloelectron volts, average yields exceeding 1(13) per second, peak intensities higher than the average by two or three orders of magnitude, controllable polarization, and pulse durations of about 2 ns. This source uses photons from a magnetic undulator in a 30-GeV electron-storage ring. Parameters of the undulator and storage ring are stringent but probably attainable with careful design and construction. Several applications are discussed