Optimization of counting conditions and simultaneous determination of Pu-238, Pu-239 and Pu-240 by liquid scintillation counting

Plutonium is the most widespread transuranic element in the environment. Its radioisotopes Pu-240, Pu-239 and Pu-238 alpha emitters with similar energies, and they are frequently quantified in radioprotection programs. These radioisotopes are usually determined with surface barrier detectors, but we have used liquid scintillation counting (LSC) with multivariate calibration (MVC) to overcome the technique's poor resolution. We discuss here preparation and measurement of counting solutions for meeting requirements of MVC methods. We tested the following variables: pulse-shape option, counting solution preparation procedure and type of vial. We also provide an example of the application of MVC using the proposed conditions.