The main focus in this study is to determine the stability of the plasma generated by a Dielectric Barrier Discharge (DBD) reactor in the presence and without glass beads as dielectric enhancement. The stability of plasma was determined based on plasma temperature which measured within plasma stream. The DBD plasma reactor was designed, fabricated and being operated in an open air system. Fiber Bragg grating (FBG) was used to measure the plasma temperature. The applied voltage was increased up to 8 kV to determine breakdown voltage and evaluate plasma stability with and without the presence of glass beads as dielectric enhancement. Experimental results revealed that plasma started to generate at applied voltage about 3.0 kV. Plasma formation found generated with stable at applied voltage 8 kV for both with and without the presence of glass beads. With the presence of glass beads, the plasma temperature found much higher about 180 °C compare with without glass beads which is about 90 °C, and yet the plasma generation is still stable.

Gafchromic external beam therapy 3 (EBT3) film has widely been used in medical field applications. Principally, the EBT3 film's color gradually changes from light green to darker color under incremental exposures by ionizing or even non-ionizing ultraviolet (UV) radiation. Peak absorbance of the EBT3 film can be used to predict absorbed doses by the film. However, until today, related researches still rely on spectrometers for color analysis of EBT3 films. Hence, this paper presents a comparative analysis between results produced by the spectrometer and a much simpler light-emitting diode-photodiode based system in profiling the color changes of EBT3 films after exposure by solar UV radiation. This work has been conducted on a set of 50 EBT3 samples with incremental solar UV exposure (doses). The wavelength in the red region has the best sensitivity in profiling the color changes of EBT3 films for low solar UV exposure measurement. This study foresees the ability of blue wavelength to profile films with a large range of solar UV exposure. The LED (light emitting diode)-based optical system has produced comparable measurement accuracies to the spectrometer and thus, with a potential for replacing the need for a multipurpose spectroscopy system for simple measurement of light attenuation.

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