αSpectroscopy Standard Measurement Method On Reference Levels Of Radon Progeny Value

The Radon Lab. of university of south china is the only lest lab in Asian areaamong the international Radon measurement organization. At present, the methods tometrological verification of Radon daughter is based on the total alpha method of lastcentury. The total alpha method is operating cumbersome. Besides, the measurementof its daughter has bigger error and costs long time. In recent years,with thedevelopment of computer and alpha spectrum method, it is possible to replace the thetotal alpha method with alpha spectrum method, and establishing an automatic, fast,accurate and reliable certificating methods become necessary. Kang Xi of Universityof south china has optimazed the measurement procedure of222Rn/220Rn by alphaspectrum method.The Automatically Alpha Spectrometry Method of Zhou Qingzhihas edited corresponding software and reprocessing of spectrum file.Based on this,Ihas optimazed sampling and measuring system and the calculation parameters hasbeen measured with accuracy.Through extensive research about “Performance study about filter have been usedto α radioactive aerosol sampling”, Selected Millipore AA type membrane filter(about0.8μm pore size) replace the existing glass fiber filter.The experiment selectsthree sampling flow rates(6.3L/min、12.3L/min、15.6L/min),Using the filter samping radon progeny and has measured recoil loss rates of the RaB’s recoil loss rates are0.3628,0.3684,0.3629respectively, aiming at the sampling and measuringenvironment in radon laboratory. It shows no significant difference, but the RaBproduced by the decay of RaA on the filter membrance samples has larger recoil loss.Using the Mylar membrane with a thickness of1.5μm to cover the samples,haseffectively eliminated the RaB’s recoil loss,and has no major impact on themeasurement system. The calculation parameters of alpha spectrum method for radon progeny has been measured with accuracy.Make alpha spectrum measurementcompared with standard measurement of total alpha method,the concentration of RaBshow big deviation. So, in the future,many research are still to be done in thisarea,we need to find the reason which cause this problem.