Measurement of radioactivity — Determination of beta emitters activities — Test method using liquid scintillation counting

ISO 19361:2017 applies to liquid scintillation counters and requires the preparation of a scintillation source obtained by mixing the test sample and a scintillation cocktail. The test sample can be liquid (aqueous or organic), or solid (particles or filter or planchet).

ISO 19361:2017describes the conditions for measuring the activity of beta emitter radionuclides by liquid scintillation counting[14][15].

The choice of the test method using liquid scintillation counting involves the consideration of the potential presence of other beta emitter radionuclides in the test sample. In this case, a specific sample treatment by separation or extraction is implemented to isolate the radionuclide of interest in order to avoid any interference with other beta-, alpha- and gamma-emitting radionuclides during the counting phase.

ISO 19361:2017 is applicable to all types of liquid samples having an activity concentration ranging from a few Bq·l 1 to 106 Bq·l 1. For a liquid test sample, it is possible to dilute liquid test samples in order to obtain a solution having an activity compatible with the measuring instrument. For solid samples, the activity of the prepared scintillation source sh