Eduardo G. Yukihara (Switzerland)
Paul Scherrer Institute Department of Radiation Safety and SecurityAuthor Of 1 Presentation
OPTICALLY STIMULATED LUMINESCENCE DETECTORS (OSLDS) FOR ULTRA-HIGH DOSE RATE PROTON DOSIMETRY
Abstract
Background and Aims
The objective of this study was to assess the use of optically stimulated luminescence detectors (OSLDs) to support radiobiological experiments for ultra-high dose rates (FLASH) proton beams.
Methods
Two experimental setups were tested to accommodate either biological samples or multiple mm2-sized Al2O3:C OSLDs. The OSLDs were read out using a protocol with a reference irradiation under known conditions to account for material differences. The experiments were conducted in a single pencil beam at the PSI Gantry 1 at a wide dose rate range of (1-3800) Gy/s. A third experiment assessed the spot reconstruction at 9000 Gy/s.
Results
The OSLDs were demonstrated to be dose rate independent with a negligible signal fading. The OSLD evaluated doses were on average (n=66) within 1 % of the nominal dose for (3 – 33) Gy for dose-rates (1 – 1000) Gy/s. The discrepancy between the OSLDs and the nominal dose was higher for the (3800-9000) Gy/s dose rates due to averaging effects of the narrow pencil beam over the OSLD surface, where a correction was demonstrated. An OSLD dose measurement was overall found to be reproducible within 1 %. The use of an OSLD grid enabled an estimation of the beam spot size and position in agreement (deviation < 2%) with radiochromic film measurements.
Conclusions
The results demonstrate that the almost point-like OSLDs are applicable for accurate proton dosimetry in ultra-high dose rates and suitable to support radiobiological experiments in water and air.