Strong reduction of radiation damage in plastic scintillators by illumination with visible light

The two most important types of radiation damage in plastic scintillators are the production of new stable absorption centers which are responsible for the permanent absorption damage and the deterioration of fluor molecules. The present work shows that both effects can be reduced considerably in the scintillator SCSN-38, if the samples are illuminated during irradiation with light of appropriate wavelength. Illumination of SCSN-38 with red light reduced the deterioration of the fluor BDB by a factor of 2, while the illumination with blue light reduced the permanent absorption damage in SCSN-38 by a factor of 4. A similar reduction of absorption was observed in clear polystyrene, the base material of most plastic scintillators.