Discoloration And Effectiveness Of Gafchromic EBT3 Film In Measuring Solar Ultraviolet Irradiance Using Spectroscopic Method
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Date
2018-07
Authors
Osman, Ummi Shuhada
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Gafchromic External Beam Therapy 3 (EBT3) films were investigated for its ability to measure the ultraviolet (UV) irradiance (dose, in mJ/cm2) exposed directly to sunlight. Five different experiments were conducted by using different EBT3 films prepared to study the effectiveness of the films towards measuring solar UV irradiance using absorbance spectroscopy technique. Those films were exposed to the solar UV irradiance at various condition of sky, duration of time and places. The discoloration of the films is dependent on the exposure time, irradiance rate and condition of the sky. The experiments were conducted under measured ambient temperature and humidity. The changes of films’ color from light green to dark green were analysed using visible absorbance spectroscopy technique. The absorbance spectra obtained from Minitab Software for all the experiments presented with quantitative analysis. The values of coefficient of determination, R2 and root mean square error, RMSEC obtained for calibration data set was 99.3 % and 414.571 mJ/cm2 respectively while for the prediction data set, the R2 and RMSEP was 97.1 % and 176.752 mJ/cm2. The value of R² and RMSE showed high correlation between UV dose and color changes of exposed EBT3 film, indicating that EBT3 film gives high effectiveness in measuring solar UV dose.
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Keywords
Discoloration and effectiveness of gafchromic EBT3 film , measuring solar ultraviolet irradiance using spectroscopic method