On the WMC density as an inverse Gaussian probability density

The probability density function (PDF) used to model the statistical behavior of avalanche photodiodes (APD), known as the Webb, McIntyre and Conradi (1974) WMC density, is shown to be an inverse Gaussian density. As a consequence, a closed-form solution for the cumulative distribution function exists. A closed-form for the cumulative distribution of the WMC PDF has not been presented in the literature before. With this result, alternate methods for the generation of WMC PDF distributed random variates are now available. These methods are reviewed and discussed.