Dosimetric characteristics of aqueous solution of crystal violet

Full text: Aqueous solution of crystal violet has been evaluated spectrophotometrically as a gamma-ray chemical dosimeter. The absorption spectra showed a maximum around 588 nm with decrease in absorption as the solution is irradiated. The response of the dosimetric system was measured at 588 and 500 nm and the response was found linear in the dose range up to 550 Gy at pH 5.6 at these two wavelengths. Similar results were obtained if change in absorption or negative logarithm of absorption (-log A) were plotted against dose. At higher doses, the plots deviate from linearity. The response of the crystal violet dosimeter during post-irradiation storage at room temperature in dark showed slight decrease in absorbance with time up to 100 days. For higher doses, the change in the response was greater as compared to the lower absorbed doses. The response of the chemical dosimetric system has also been investigated under different storage conditions of light and temperature. Post-irradiation stability in fluorescence light showed very slight decrease, but storage in diffused sunlight showed significant decrease in the response up to 100 days. While stored at lower temperature (4 deg. C), there was a small decrease in the absorbance, however at higher storage temperature (40 deg. C), the decrease in the absorbance was significant. Possible applications of the crystal violet dosimeter for low dose food irradiation applications will be discussed