Al <sub>2</sub> O <sub>3</sub> :C optically stimulated luminescence dosimeters (OSLDs) for ultra-high dose rate proton dosimetry
Jeppe Brage Christensen, Michele Togno, Konrad P. Nesteruk, S. Psoroulas, D. Meer, Damien C. Weber, Antony Lomax, E.G. Yukihara, Sairos Safai
Abstract
Abstract The response of Al 2 O 3 :C optically stimulated luminescence detectors (OSLDs) was investigated in a 250 MeV pencil proton beam. The OSLD response was mapped for a wide range of average dose rates up to 9000 Gy s −1 , corresponding to a ∼150 kGy s −1 instantaneous dose rate in each pulse. Two setups for ultra-high dose rate (FLASH) experiments are presented, which enable OSLDs or biological samples to be irradiated in either water-filled vials or cylinders. The OSLDs were found to be dose rate independent for all dose rates, with an average deviation <1% relative to the nominal dose for average dose rates of (1–1000) Gy s −1 when irradiated in the two setups. A third setup for irradiations in a 9000 Gy s −1 pencil beam is presented, where OSLDs are distributed in a 3 × 4 grid. Calculations of the signal averaging of the beam over the OSLDs were in agreement with the measured response at 9000 Gy s −1 . Furthermore, a new method was presented to extract the beam spot size of narrow pencil beams, which is in agreement within a standard deviation with results derived from radiochromic films. The Al 2 O 3 :C OSLDs were found applicable to support radiobiological experiments in proton beams at ultra-high dose rates.