OC-0248: Characterization of the temperature dependence of BCF plastic scintillation detectors
Radiotherapy and Oncology
S96 2 nd ESTRO Forum 2013 detector volume. Narrow field photon beam data with the W1 detector were compared to the data measured with other small field detectors, including diodes and micro ion chambers. Results: The scintillator response remained linear within 0.2% at the highest dose rate of 2400 MU/min. Dose rate response of the W1 detector tracked that of a Famer chamber to within 0.5% when the instantaneous dose rate was varied by a factor of five with varying detector to source distance.
... o source distance. The energy dependence of the scintillator response was within the measurement uncertainty of 0.5% when the dose in the sensitive region of the detector was referenced to that measured by an ADCL calibrated farmer chamber in water. Both 6MV and 10MV FFF beam depth dose measurements for 3x3 cm and 10x10 cm field sizes with the W1 detector agreed with the standard scanning ion chamber data within 0.6% beyond the build-up region down to 30 cm depth in water. Total output factors were in agreement with the diode and micro ion chamber results within 0.5% except at the smallest field of 0.5x0.5 cm, where the discrepancies of 2-3% were attributed to the non-water equivalence of diode and steel central electrode of the ion chamber response. There were no significant differences in the scintillator response between the parallel and perpendicular orientations to the beam axis except at the smallest field sizeof 0.5x0.5cm where the longitudinal size (3mm) of the scintillator became comparable to the field size when placed perpendicularly to the beam axis. Conclusions: The newly available W1 scintillator provides a robust and reliable dosimetry system for most challenging small field photon beam measurements suitable for accurate stereotactic beam commissioning work.