Abstract: In order to accurately measure the radon activity,different methods of radon activity measurement were established in all countries.The traditional methods of radon measurement,including the ionization chamber method and the scintillation chamber method of radon measurement are used as relative method of radon activity measurement,with a higher degree of uncertainty,and the value of the source depends on the characteristics of standard material of radium.In this paper,the absolute measurement methods of radon activity measurement are introduced in this paper,comprising the absolute measurement method of condensation small solid angle,the absolute measurement method of multi-electrode proportional counter and the absolute measurement method of small scintillation chamber.Through the introduction and analysis of the theory and experimental device,the characteristics of various absolute measurement methods are discussed and compared.

Key words: Radon activity, Standard measurement, Absolute measurement, Small solid angle, Proportional counter, Small scintillation chamber