Suspension polymerization method for preparing plastic scintillation microspheres

Plastic scintillation microsphere (PSm) is a micron-sized plastic scintillator, and it is an organic scintillation material with good application prospects in the field of radioactivity analysis. However, the lack of simple industrial synthesis methods could limit bulk production of PSm with a reasonable cost. In this study, PSm materials were prepared via suspension polymerization and the repeatability of both the synthesis conditions and the radioactivity measurement performance were evaluated. Results indicated that PSm with a particle size distribution ranged around 90–200 μm can be reproducibly synthesized under certain conditions. Consistent counting efficiency for the 14 C measurement in liquid samples using PSm has been obtained as long as sufficient PSm was added into the scintillation vial to completely cover the liquid volume. By comparing the spectral widths of samples with different concentrations of fluors, optimal PPO concentration of 1.5% and bis-MSB concentration of 0.015% was chosen to obtain a good light yield and a counting efficiency of up to 43.3% for 14 C in water. Furthermore, it was observed that the 14 C counting efficiency of PSm would be significantly affected by the quenching of the solution.