Velocity of hypersonic waves in liquid oxygen

Velocities of hypersonic (3–5 GHz) waves in liquid oxygen have been determined by thermal Brillouin scattering techniques. The incident radiation (λ = 5145 Å) was obtained from a stabilized single-mode argon-ion laser, and the scattered radiation was analyzed at 90° with a piezoelectrically-scanned Fabry-Perot spectrometer. Measurements cover the temperature range from the triple point (54.35°K) to the normal boiling point (90.18°K), and in this range the velocities were observed to decrease linearly with increasing temperature from 1193 to 909 m/sec. These results are compared with ultrasonic (1.2 MHz) velocities as measured by Van Itterbeek and Van Dael at temperatures above 61°K, and no dispersion effects are evident at least up to 3.6 GHz.