Two-dimensional real-time dosimetry system using micro-and nano-(C44H38P2)MnCl4 radioluminescence coatings

Abstract

This study investigates the impact of particle size on the radioluminescence (RL) response of (C44H38P2)MnCl4 coatings, which have been made with five crystal size fractions ranging from ≈200 nm to 75 μm. These coatings underwent testing using a bespoke 2D real time prototype system, comprising a camera affixed to the head of a linear accelerator and oriented towards the flexible RL coatings positioned at the beams' isocentre. Upon irradiation, a consistent RL peak at 525 nm was observed across all particle size fractions, albeit with varying light intensities. Minimum detectable dose-rate values were determined to be 0.05 Gy/min, and even for the coating exhibiting the lowest light intensity (Nano-01), individual pulses could be discerned, yielding a minimum detectable dose of 0.28 mGy. Basic dosimetric tests were conducted to characterize these coatings, evaluating their response with respect to dose-rate, dose, and small field relative responses. Subsequently, the coating demonstrating the most favorable dosimetric properties underwent further analysis to assess its suitability for machine quality assurance (QA). These tests included the standard alternating leaves, chair, and pyramid checks routinely employed for QA purposes.