Impact of voltage fluctuation on dose delivery of BJ-6B accelerator

Abstract

Objective To study the impact of main source voltage fluctuation on dose rate and dose delivery accuracy of BJ-6B accelerator. Methods The accelerator was calibrated by a voltage regulator at an output voltage of 332 V. The main source voltage fluctuation was simulated by changing the output of voltage regulator within the range of 321 - 338 V. The change of dose rate was recorded. Using a water phantom, each absorption dose was measured five times and averaged along the central beam axis at the depth of 1.5 cm, 5 cm and 10 cm, respectively, with the conditions of monitor unit: 100 MU ,field: 10 cm× 10 cm and SSD = 100 cm. The impact of voltage fluctuation on dose rate and dose delivery of BJ-6B accelerator was analyzed. Results Voltage fluctuation had an significant effect on dose rate. In a certain range, dose rate and absorption dose at different depths increased as the output voltage increased. Conclusions It is essential to equip the BJ-6B accelerator with a high accurate voltage stabilizer, and the voltage stabilizer must be adjusted to its highest accuracy. Key words: Voltage; Dose rate; Dose accuracy