Andrea Giammanco (Belgium)
DoseVue N.V. R&DAuthor Of 1 Presentation
FASTER THAN LIGHT: CAN SCINTILLATORS GUIDE ELECTRON FLASH EXPERIMENTS?
Abstract
Background and Aims
The radiobiological study of the FLASH effect requires accurate and reliable dosimetry. As scintillators are promising candidates, this work presents a first characterization of their response at UHDR, suggesting solutions to account for possible saturating effects.
Methods
Five scintillating fibers, one clinical and two experimental Y2O3:Eu-based scintillators (DoseVue N.V., Belgium) and two experimental Al2O3:C-based scintillators (SCK CEN, Belgium), were irradiated using the ElectronFlash system (SIT, Italy). Linearity with dose was validated by varying the number of pulses for both experimental Y2O3:Eu-based scintillators. Dose per pulse (DPP) linearity was investigated in all scintillators by varying pulse duration and the distance from the linac exit window (SSD). Pulse scheme stability was investigated by changing of the pulse repetition frequency (PRF).
Results
Good linearity with dose (R²>0.99) was observed in both experimental Y2O3:Eu-based scintillators. Linearity with increasing pulse duration (R²>0.95) and an inverse squared relation between DPP and SSD (R²>0.95) were observed in 4 out of 5 scintillators. However, a concave curvature in response, suggesting saturation, was observed for all scintillators. This effect was more pronounced for the smaller applicator diameter. Our results showed reduced saturation effects when increasing integration time as well as when reducing signal intensity. All scintillators showed a decreasing response with increasing PRF.
Conclusions
The promising characteristics of scintillators as on-line dosimeters for UHDR were validated and possible solutions to reduce saturation effects have been evaluated. Further research on the response by varying PRF is needed.
This work is part of the 18HLT04 UHDpulse project which received funding from the EMPIR programme.