Characteristics of a Simple Radon Generator for Calibration

Abstract

This paper describes fabrication and characteristics of a radon generator. The generator consists of a stainless steel container having a volume of 100 liters and a radium bromide source to obtain radon gas. An effective production rate of ²²²Rn was estimated from the absolute activities of ²²⁶Ra, ²¹⁴Pb and ²¹⁴Bi, which were measured by gamma-ray spectrometry using a germanium detector. The emission rate of ²²²Rn from the radium bromide source into a gas phase was estimated to be 1.45×10⁴ atoms per second by subtraction of ²¹⁴Pb (or ²¹⁴Bi) activities from the activity of ²²⁶Ra. The radon gas concentration of the air in the generator was estimated to be 1.45×10⁵ [Bq/m³] . Effects of temperature and humidity of the air in the container were sufficiently small under usual condition.