Derivation of Beta/Alpha Ratios for Predicting Radon/Thoron Progeny Interference with Radiation Monitors
L.A. Rathbun (Fluor Hanford, Inc.)
During known temperature inversions, the ratio of beta counts to alpha counts along with increases in both the beta and the alpha counts measured on an air filter paper can be used to predict radon and thoron progeny levels which may cause interference with the proper operation of personal contamination monitors and continuous air monitors. The increase in beta and alpha counts can be compared with a baseline previously determined during non-inversion conditions. The beta-to-alpha ratio can be compared with values calculated from theoretical considerations of representative radon and thoron progeny build up and decay. This approach eliminates the need for plotting repeated graphs of beta-to-alpha ratios from empirical data.