Application of Radionuclide Signatures to Short Duration/Pulse Atmospheric Releases

The global background of detectable radioactive emissions continues to increase not only in concentration, but with greater variability. Recent world events such as the Fukushima-Daiichi disaster, nuclear weapons tests, and accidental/unplanned venting underscore the need to accurately attribute sampled radionuclides to their sources. Significant sources of background radionuclides, in addition to reprocessing facilities, include medical isotope production facilities, and nuclear power plants. Most importantly, these combined background sources will contribute significantly to measurements intended to characterize source and evolution from samples, including underground detonations where material may be sequestered for a period of time. In these cases, the background order of magnitude may equal or exceed the detonation release. This paper will demonstrate how wavelet techniques can be used to discriminate transient emissions from background sources and provide a significant source of information to improve the analysis of high fidelity observations from existing networks such as the International Monitoring System used in support of the Comprehensive Test Ban Treaty.