LAUSR

We introduce a low-frequency torsional oscillator suitable for studies of quantum fluids and solids. It operates at frequencies of ∼100 Hz, achieves velocities of several cm s−1, and exhibits a quality factor of Q ≃ 3 × 10 4. In order to reach such velocities at this relatively low frequency, the oscillator amplitude must exceed 100 μm, which would be impracticable for a conventional capacitor-driven device where the drive is applied parallel to the main motion and there are correspondingly large changes in the separation of the capacitor plates. For the different geometry of the oscillator that we now describe, however, the separations of both the drive and detect capacitor plates remain constant regardless of the amplitude of oscillation. We discuss its design and report our initial tests of its performance.