Scatter-air ratios for telecobalt

Cunningham (1972) showed that it is possible to determine scatter-air ratios for large radii by extrapolation. He proposed the extrapolation of the scatter-air ratio divided by radius, because this function gradually decreases to zero as the radius increases. The author used his method and the data for scatter-air ratios published by Gupta and Cunningham (1966) and the results of the extrapolation are presented.