Signal searching in return spectra and decision making using minimal integration time

Neutron scanning techniques are becoming important tools in the search for chemical agents, explosives, drugs, nuclear material and other hazardous materials in government buildings, airports, military installations or public areas. Each nucleus when excited emits quanta of gamma radiation at characteristic energies. The element can be physically located and identified by these energy lines. It is important to identify these lines in a minimal amount of time in order to increase the number of items that are searched and to allow fast flow of people and their possessions into and through facilities. This paper develops a mathematical model of the signal significance and search stopping in a minimal time. The stopping decision is important as the vast majority of searches are negative. The economic benefit for a minimal search time is great, as millions of searches will be conducted daily.