We report on our attempt to reproduce the 228Th decay enhancement under the effect of power ultrasound claimed recently in the literature. The evolution of natural thorium isotopic composition (232Th, 230Th, and 228Th) in various aqueous solutions submitted to 20 kHz power ultrasound (0.18 W mL−1, 20 ºC, Ar). The radioactivities of the three isotopes of thorium (232Th, 230Th and 228Th) were followed by α liquid scintillation counting technique. No change was detected during ultrasonic irradiation. Our results demonstrate that under the studied conditions the rate of Th isotopes radioactive decay is not modified under the effect of ultrasound on aqueous solutions of thorium salts.
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