BLACKBODY SOURCE AND DETECTOR OF BALLISTIC QUASI-PARTICLES IN HE-3-B - EMISSION ANGLE FROM A WIRE MOVING AT SUPERCRITICAL VELOCITY

Using a new quasiparticle detector and source consisting of a blackbody radiator, we have made the first measurements of the divergence of a beam of quasiparticles produced by a vibrating-wire resonator moving at supercritical velocities in superfluid He-3-B at the zero-temperature limit. At velocities just above the critical velocity of DELTA/3PF we see a very narrow beam directed along the direction of motion of the wire. As the maximum wire velocity increases the beam spreads to saturate at a half-angle divergence of approximately 55-degrees at a maximum velocity of order DELTA/PF.