A systematic characterization of plastic scintillation dosimeters response in magnetic fields: I. Experimental measurements.

Objective.This study aims to evaluate the performance of five distinct plastic scintillation dosimeters (PSDs) in magnetic fields, as well as to validate the accuracy of the hyperspectral approach for stem-effect correction. The effect of the magnetic field on different base core materials and components within the PSDs was also investigated, as well as the effect of field size and orientation.Approach.Each PSD was placed at 5 cm depth in a water tank inside an electromagnet gap. Magnetic fields, between 0 and 1.5 T, were set to be perpendicular to the 6 MeV photon beam and to the PSD axis. The detector axis was either parallel or perpendicular to the photon beam. Different field sizes were used. The hyperspectral technique was validated and used to determine the scintillation, fluorescence and Cherenkov components at different magnetic fields.Main results.The hyperspectral method accurately removes stem effects in magnetic fields, even when calibration is performed at 0 T. The stem light yield shows good agreement with clear fiber measurements, with relative differences within 2.0%. In the parallel orientation, the corrected PSD response is highly symmetric relative to magnetic field polarity, with a maximum variation of only 0.2% from unity. Scintillation light yield increases with magnetic field by 3.6%-6.25% depending on PSD properties. Cherenkov light yield varies up to 230% and down to 0.30% of the 0 T value, depending on magnetic field polarity. The impact of magnetic fields depends primarily on the properties of the scintillator itself, with polyvinyltoluene-based probes showing greater sensitivity than polystyrene-based probes. The inclusion of a wavelength shifter has minimal on the magnetic field's effect on scintillation light yield. Normalized scintillation light yield decreases with smaller field sizes.Significance.PSDs are well-suited for accurate dosimetry in magnetic fields, provided that accurate stem-effect correction techniques are applied. The scintillator properties play a significant role in determining the PSD's sensitivity to magnetic fields. The hyperspectral method is a robust approach for accurate stem-effect removal in such conditions.