Evaluating the energy dependence of various polystyrene based plastic scintillators

Abstract

Plastic scintillation detectors (PSDs) have been extensively tested as in-vivo dosimeters for brachytherapy dosimetry, but they are known to suffer from an energy dependence in low energy photon beams, an unwanted characteristic of any dosimeter. It has been demonstrated that the base material of the plastic scintillator can have a significant impact on the PSDs energy dependent behavior in x-ray beam voltages from 25 to 100kVP (Peralta and Rêgo, 2014). In this work, a comprehensive range of polystyrene based PSDs are studied to determine if the scintillator composition and geometry has any impact on their energy dependent behavior in superficial x-ray beams in the 30 to 150 kVP range. The relative response of each scintillator tested was found to vary by up to 77% across the 0.014–0.061 MeV effective energy range, with a maximum variation in relative response of 13.1% between the different scintillators. These results demonstrate the PSD diameter, formulation and cladding do not significantly impact the scintillator performance in the studied energy region.