Dosimetry of ultra-high dose rate electron beams using thermoluminescence and optically stimulated luminescence detectors.

Autor: Motta S; Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland.; Department of Physics, ETH Zürich, Zürich, Switzerland., Dal Bello R; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Christensen JB; Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland., Bossin L; Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland., Yukihara EG; Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland.
Jazyk: angličtina
Zdroj: Physics in medicine and biology [Phys Med Biol] 2024 Feb 02; Vol. 69 (3). Date of Electronic Publication: 2024 Feb 02.
DOI: 10.1088/1361-6560/ad1cf5
Abstrakt: Objective. The aim of this work is to investigate the dose rate dependence of thermoluminescence and optically stimulated luminescence detectors (TLDs and OSLDs) in a wide uniform ultra-high dose rate electron beam and demonstrate the potential use of TLDs and OSLDs to correct the ion recombination in air-filled ionization chambers. This study avoids previously reported complications related to the field size and homogeneity. Approach. Two types of OSLDs (BeO and Al 2 O 3 :C) and three types of TLDs (LiF:Mg,Ti, LiF:Mg,Cu,P, CaF 2 :Tm) were irradiated simultaneously in a uniform 16 MeV electron beam generated by a clinically decommissioned C-Arm LINAC, modified to deliver doses per pulse between 8.3 × 10 -4 Gy and 1.255 Gy, corresponding to instantaneous dose rates between 2 × 10 2 Gy s -1 and 3 × 10 5 Gy s -1 . A prototype ultra-thin parallel plate ionization chamber was employed as reference detector. Main results. Reproducible results were achieved both at conventional (standard deviation of the data <2%) and at the highest dose per pulse (standard deviation of the data <4%). No trend in the dose rate response of the TLDs and OSLDs was observed in the investigated dose per pulse range. The Al 2 O 3 :C OSLD was found to be the most precise detector, with a standard deviation of the data <2% at all investigated dose rates and dose levels. Significance. The dose rate independence of the investigated TLDs and OSLDs make them good candidates for dosimetry at ultra-high dose rates, at least up to 3 × 10 5 Gy s -1 . A dose rate independent method to measure the dose per pulse is proposed, which can be applied to characterize ultra-high dose rate electron beams and correct for ion recombination in ionization chambers.
(Creative Commons Attribution license.)
Databáze: MEDLINE
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