Ortho-positronium reactions in water studied by positron annihilation age-momentum correlation

Hirade, Tetsuya  ; Oka, Toshitaka   ; Lee, J.

OH radical formed in water by ionizing radiations is very strong active oxygen and has very short lifetime. There was no methods of direct observation of the OH radical, but it is becoming possible to observe it by ortho-positronium, because of the existence of reaction between OH radical and ortho-positronium. Positron annihilation age-momentum correlation measurement (AMOC) is the best method to detect the ortho-positronium reactions. We investigated the temperature dependence of OH radical reaction and found out that The reaction is faster at higher temperatures probably because of the faster diffusion.