Abstract: Experimental methods of total α and total β radioactivity in water using low-background α and β measuring system are discussed in this article. Based on a series of comparative experiments, the storage time and temperature of samples, sample preparation method and placement time, which may influence the experimental results, are put forward to reduce the experimental uncertainties. Radon dissolved in water such as well water, tap water and groundwater or infrared lamp may interfere with the counting. After the sample preparation, it is advisable to put the sample at room temperature and dry environment for at least 3 hours before measurement. It shows that storage temperature and storage time have no significant effects on total α and total β radioactivity of water under the condition of sealed storage. Furthermore, acidification of water samples with sulfuric acid recommended by the current national standard, can effectively avoid moisture absorption so as to reduce experimental uncertainty.

Key words: total α radioactivity, total β radioactivity, storage conditions, radon