Radiation measurements with heat-proof polyethylene terephthalate bottles

This study demonstrates that the energy resolution of a newly developed 100 per cent pure polyvinyltoluene (PVT) plate allows its use as a base material for a plastic scintillator. The energy resolution, which is a key element for high-performance radiation detectors, was Delta E/E = 8.41 +/- 0.07% (full width at half maximum (FWHM)) for 976 keV K-line conversion electrons from a (207)Bi source. On the basis of results from (207)Bi and (137)Cs sources, the observed energy resolution of the PVT plate, Delta E/E = 8.2/E(1/2)% (FWHM), was slightly better than that of a typical plastic scintillator (BC-408), Delta E/E = 8.7/E(1/2)% (FWHM), with E in units of MeV. These results prompted us to search for other new base materials for plastic scintillators. In this study, we examined polyethylene terephthalate (PET) bottles, a common source of domestic plastic waste. We demonstrated that a lump of heat-proof PET bottles is fluorescent; moreover, there is excellent compatibility of the fluorescence with the quantum efficiency of typical photomultiplier tubes. This inexpensive source of plastic appears suitable for radiation measurements and as a base material for plastic scintillators. Future studies on the radiation response of plastics should lead to the development of higher performance and more eco-friendly radiation detectors.