Patent ID: 7329872

Claim:
A method for detecting an element, comprising: providing a gamma-ray spectrum having multiple peaks of a target which may or may not have a small amount of a known element to be detected; defining a region of interest within the gamma-ray spectrum which corresponds with the known element which is to be detected and which may or may not be present; determining an approximate first channel for the region of interest within the gamma-ray spectrum; defining a search region for the actual first channel of the region of interest, and which is defined by a number of channels on the opposite sides of the approximate first channel; defining a first channel of the region of interest which has a number of counts; defining a last channel of the region of interest which has a number of counts; calculating the number of counts of a plurality of channels which are located adjacent to the first and last channels; calculating background counts in the region of interest for the small amount of the element to be detected based, at least in part, upon the number of counts in the plurality of channels which are located adjacent to the first and last channels; calculating the total counts in the region of interest; calculating net counts due to the small amount of the element to be detected by subtracting the background counts from the total counts in the region of interest; calculating a statistic from the net and background counts in the region of interest for the small amount of the element to be detected; calculating a probability value based upon the calculated statistic to derive a detection confidence factor indicating the degree of assurance that the small amount of the element to be detected is present or absent; providing a standard Gaussian cumulative distribution function; identifying on the standard Gaussian cumulative distribution function a point which corresponds to the calculated statistic; deriving the resulting confidence factor from the point which corresponds to the calculated statistic; and displaying a message to an operator indicating the presence or absence of the element to be detected based, at least in part, upon the confidence factor.