EFFECT OF TEMPERATURE AND LIGHT ON THE RESPONSE OF AN AQUEOUS COUMARIN DOSIMETER

The aqueous solution of coumarin has been studied spectrophotometrically as a gamma-ray dosimeter and effects of temperature and light conditions on the stability of response during post-irradiation storage have been studied. Post-irradiation storage at room temperature in dark showed that after a very small increase in absorbance within the first 6 d, the response of the dosimeter was stable up to 42 d. At lower temperature (-15 degrees C), there was some decrease in absorbance within the first 24 h followed by a stable response up to 35 d. For post-irradiation storage at higher temperatures (40, 60 degrees C) the dosimeter, apart from some initial increase in absorbance, showed a nearly stable response up to 25 d. The effect of different light conditions during post-irradiation storage has also been studied. When stored in fluorescent light the response was almost stable from 6 d till about 40 d. In diffuse sunlight, the response was stable up to about 35 d at 360 nm and 370 nm but showed a somewhat unstable behavior at 347 Nm. The dosimetric solutions were unstable when exposed to direct sunlight.