Actinometry of intense UV lights from ArF, KrF and XeF excimer lasers has been studied with a ferrioxalate chemical actionometer. The relation between the number of photons per pulse (N) and the absorbance change per pulse (ΔA) at 510 nm is expressed by using a first-order function, N=a·ΔA-b. (a, b: numerical constants characterized by a laser-wavelength). The experimental errors in this method were 4.8, 5.2, and 1.6% for ArF, KrF and XeF excimer lasers, respectively. The results prove that the ferrioxalate chemical actinometer is satisfactorily usable as an actinometer for excimer lasers.
