FABRICATION OF A SILICON-BASED SUPERFLUID OSCILLATOR

We have constructed an integrated superfluid oscillator using various silicon processing techniques, including micromachining and electron b eam lithography. This device has the advantage of a very small interna l volume (0.72 mm(3)). This makes it insensitive to spurious external acoustic noise which has limited the performance of larger experiments . We have tested the performance of this device in two configurations, one with a single micro-aperture and another with an additional fine tube. Both configurations demonstrate macroscopic quantum phenomena in superfluid He-4 at low temperatures (0.25 K < T < 2.2 K) and have bee n used to study these effects in detail.