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.