THE USE OF ALUMINUM-ALLOY 5056 FOR HIGH-Q MECHANICAL OSCILLATORS AT LOW-TEMPERATURES

Measurements of the quality factor (Q) and period (P0) of two A1 5056 torsional oscillators are presented as a function of temperature from 0.02 to 1.2 K. The 5056 alloy is found to have Q's of order 10(4) at room temperature and 10(7) below 4 K. In addition to having an extraordinary high Q, we also find that the temperature dependence of the reduced period, DELTA-P/P0, is extremely weak at low temperatures, making this material well suited for superfluid helium film studies. A technique for attaching thin dielectric substrates to the torsion member of one of the oscillators is also discussed.