Determination of effective backscatter volume

An attempt is made to estimate the effective volume of a density gauge in the backscatter mode. The first and second scatter collision densities are determined using Monte Carlo methods. Statistical estimation is used to determine the response from each collision site; from this, the response densities are determined. The response densities are used to determine the contribution each volume element makes to the effective volume of the system. The requirements for the method used to determine the effective volume are (a) that the method be reasonable in simple or obvious geometrics, (b) that the effective volume approach a limit as the choice of volume clement size decreases, and (c) that the effective volume approach a limit as the real volume becomes infinite.