INVESTIGATION OF BALLISTIC PHONON PROPAGATION IN QUARTZ BY THE TIME-OF-FLIGHT METHOD

The ballistic phonon propagation in alpha-quartz is measured in direct ions z and y, for different bolometer currents, by the time-of-flight method. For higher currents on time-dependent bolometer signal curves more singularities are observed than it was reported earlier. On the b asis of calculations the observed singularities are explained as separ ately detected phonon modes and the increase of their number is connec ted with a diminution of the bolometer active area by increase of bolo meter current for very thin aluminium bolometers.