Patent ID: 8969825
Filing Date: 2015-03-03
Classification: G01T

Abstract:
1. A non-transitory computer readable medium performing a system implemented method, the method comprising the steps for identifying a nuclear explosion by radioactive isotopes of krypton and xenon by measuring, at time t after an event, signals Ã i (t) describing a change in total activity of each isotope in the atmosphere near a measuring station; building relations between isotope activities and time with no account taken of separation and relations of isotope activities drawn from measured points in reverse time for all fission types under consideration; determining a separation interval [t H , t K ]; setting a time grid within the separation interval [t H , t K ]; forming fission type combinations; calculating t q for each grid node within the separation interval and for each combination a two-dimensional signal A describing values of “specific” activities of each isotope against the separation time t q and measuring time t and potential source (of fissionable material and neutron energy); setting root-mean-square values σ(Ã i (t)) for errors in measured signals Ã i (t) and errors σ(a ij (t q , t)) in the two-dimensional signal elements {a ij (tq,t)}; setting quantities γ1,γ 2 defining accuracy of signal estimates ; identifying a nuclear explosion by means of forming a signal J 1 defining accuracy of a solution, which is obtained from a sum of squares of difference between signals Ã i (t) and products obtained by multiplying lines of a two-dimensional signal {a ij (tq,t)} by values of signals, and a signal J 2 defining a type of a signal; forming limitation signals and a target signal (target function) from the signals J 1 and J 2 in the set combinations; and finding, with the use of an iteration process and subject to specifying at each iteration, two-dimensional signal values {a ij (tq,t)} for elements of the ρN j signal; determining, according to the elements of the signal, point estimates for activity contributions of each possible fission type to total activity; selecting an optimal combination of fission types according to a sum of discrepancy squares; and determining whether a nuclear explosion by radioactive isotopes of krypton and xenon has been identified.