Study On The Measurement And Control Of The Unattached Fraction Of Radon Progeny In Radon Chamber

The research on the unattached of radon progeny involves important fields such as radiation protection and environmental science.It is an important basis for estimating the dose of human lung tissue.It is even more important to meaure and controlt the unattached of radon progeny from the perspective of metrology.On the basis of establishing a steady-state automatic control chamber,this paper carries out research work on the measurement and regulation of the unattached of radon progeny.At present,there is a large amount of basic research content on the unattached of radon progeny in the atmospheric environment at home and abroad,especially in the use of parallel plates or diffusion groups to measure the unattached of radon progeny has become mature.However,the measurement and regulation of the unattached of radon progeny in a stable closed space has not been reported.Therefore,based on the fan model theory,this study first established a new way to collect the radon progeny,and assembled a new measuring device for measuring the unattached fraction of radon progeny.The equilibrium equivalent concentration of each radon progeny can still be calculated using the least squares method while collecting.Secondly,in order to realize the steady state control of the radon progeny field in the chamber,and to facilitate the subsequent precise control of the unattached fraction of radon progeny,this study not only carried out an all-round fine of the diverticulum from the aspects of radon concentration,temperature and humidity.In the transformation work,two sets of Model 3475 and Model 3475 aerosol generating devices were built to realize the effective regulation of the unattached fraction of radon progeny and ensure the diversity of experimental data.The experimental results show that the unattached fraction of radon progeny has a decreasing trend with the increase of aerosol concentration,and the unattached fraction of radon progeny equilibrium concentration is in the range of 0.94%-25%,which is consistent with relevant research at home and abroad.General conclusions;At the same time,according to the regulatory data,the formula for regulating the unattached of aerosols and aerosol concentration applicable to the ionization chamber of China Institute of Metrology is given.Finally,the study evaluated the uncertainty of the experimental results under the current national standards.In addition to the aerosol concentration in the bottom state(<200p/cc),the uncertainty of other measurement results can be maintained at around 10%..