Impact of liquid scintillator manufacturing date on alpha-beta counting efficiency and resolution.

This study compares the performance of three batches of OptiPhase HiSafe-3, each with different production and expiration dates, in order to assess the impact of batch age on the counting efficiency of organic liquid scintillators. Three radioactive sources were examined: Sr-90 (low energy β emitter), Ra-228 (ultra-low energy β emitter), and Am-241 (α emitter). An Ultra-Low-Level Liquid Scintillation Spectrometer was used to obtain all measurements, while WinQ and EASYView software were used for data analysis. The findings demonstrated that, when maintained properly, all three batches of scintillation cocktail continued to be functional even after their formal expiration dates. For α particles and high energy β emitters, the scintillators demonstrated almost complete efficiency; however, for low energy β particles, they performed less well, due to both quenching and instrument sensitivity constraints. Optimisation of Pulse Shape Analysis (PSA) calibration was, however, found to usefully increase β-particle detection. These results improve knowledge of quenching effects and offer useful recommendations for maximising liquid scintillation cocktail use, calibration, and preservation in radiation labs.