The aqueous coumarin system as a low range chemical dosimeter

Abstract

A chemical dosimetric system, aqueous coumarin, has been developed. The dosimeter can be used to measure doses in the range 10–6000 rad using fluorescence method and in the range 5–56 krad using optical absorption measurements. The energy dependence of this dosimeter was studied and it was found that the response decreases by about 9% at energies encountered in deep X-ray therapy as compared to its value for cobalt-60 gamma rays. However, at diagnostic X-ray energies (80 kV), the response is less by about 36%. The dosimeter is independent of dose rate up to about 100 rad min⁻¹ but the response decreases as the dose rate is increased. It is independent of temperature during irradiation up to 29°C but the response slightly increases beyond this temperature. The dosimeter also shows good pre- and post-irradiation stability.