Abstract
A filamentary wire resonator will generate quasi-particles in 3He-B when driven beyond a critical velocity. By using such a resonator as a source of quasi-particles and a second wire resonator as a quasi-particle detector, we have been able to emit and detect a ballistic quasi-particle beam over a distance of 3 mm in 3He-B at temperatures below 0.3 Tc. From the preliminary experiment the momentum of the quasi-particle beam can be measured and a direct (but as yet very approximate) measurement made of the quasi-particle mean free path.