Abstract: To rapidly assess the radioactivity levels of solid samples such as soil and sediments, the determination of gross alpha and gross beta radioactivity can be employed as a rapid screening technique to preliminarily evaluate the contamination level of samples and provide assessment support for regulatory authorities.In this paper, the particle size for sample disk loading and the sample loading amount were optimized, and 100-mesh sifting together with a mass thickness of 0.015 g/cm² were determined as the parameters for optimal efficiency.The thick source method was adopted for the measurement of gross alpha and gross beta radioactivity, and verification tests were conducted across different laboratories using samples of different matrices at three activity concentration levels (high, medium and low).The results demonstrate that the minimum detectable activities of gross alpha and gross beta satisfy the requirements for environmental sample analysis; the relative standard deviation of the measurements is less than 20%, and the spiked recovery ranges from 70% to 130%, which can guarantee the comparability and traceability of the measurement results.

Key words: soil, sediment, radioactivity level, thick source method