The pulsed ultrasonic cavitation technique was employed to measure the dependence of the thresholds for emission of subharmonic and light on the concentration of dilute solutions of NaCl in distilled water. The concentration was varied from 10-9 d/cm3 to saturation, for different values of the inverse duty ratio. Preceeding results indicate an increase of both thresholds with concentration. In the case of very low values of concentration (10-9 to 10-3 g/cm3) the trend is reversed. Possible mechanisms that can explain the presence of the minimum, based on the dynamics of nuclei and bubbles population are indicated.
