HIGH-RESOLUTION SOUND-VELOCITY MEASUREMENT IN LIQUID-HE-3 USING PATH-LENGTH MODULATION TECHNIQUE

Employing path length modulation technique, we are able to make high r esolution sound velocity measurements (approximate to 10 ppm) with a r elatively short path length. We present new values of F-2(s) calculate d from zero- and first-sound velocity measurements at 12.6 MHz in liqu id He-3 over the pressure range of 0.6 to 14 bar. We also report a new ly observed behavior in high frequency zero-sound velocity at 113 MHz near the superfluid transition temperature at 0.6 bar.