A method for 237Np determination with LSC in the experiment of neptunium sorption onto bentonite

A method was developed for the determination of 237Np with liquid scintillation counting (LSC) in the batch experiment of neptunium sorption onto bentonite. Before we use the pulse shape analysis (PSA) technique to discriminate α/β emission, a new approach was developed to set the optimum PSA by measuring a mixed α/β emitters sample and a background sample. The mathematic treatment of neptunium spectrum indicated that at the selected PSA-level of 38 approximately 86 % of the total α emission is detected, which is suitable for the determination of samples in the batch sorption experiments. Moreover, we confirmed that, at mass to volume radio 0–10 g/L the bentonite suspension in samples has a little impact on LSC determination. Thus, sorption percentage can be easily obtained by counting equivalent amount of suspension and supernatant from the same sample. Therefore, 237Np samples of batch sorption experiments could be detected with LSC quickly and effectively.