HE-3 IN 99.5-PERCENT POROUS AEROGEL AT THE NORMAL-SUPERFLUID TRANSITION

We have used a torsional oscillator to measure the superfluid density and dissipation near the superfluid transition of He-3 in aerogel of 9 9.5% porosity. We used a new cell (constructed at Penn State) for whic h the aerogel was grown in the pores of a similar to 100 mu um silver sinter. The cell was tested with He-4 and showed no signs of the secon d-sound resonances that have interfered with previous torsional oscill ator measurements. The measurements with He-3, presented here, were ta ken at pressures of 1.34 and 4.13 bars. observed values of rho(s)/rho in the T-->0 limit of 0.05 and 0.14 respectively. Our measurements sho w an increase in the dissipation on warming through T-c. This series o f measurements is ongoing and temperature sweeps at various pressures are planned.