Wavelet analysis of gamma-ray spectra

Since September 11, 2001, there has been increasing interest in providing first responders with radiation detectors for use in the search for and isotope identification of potentially-smuggled special nuclear material (SNM) or radiological dispersal devices (RDDs). These devices are typically comprised of low-resolution detectors such as NaI, thus limiting their identification abilities. We present a new technique of wavelet analysis of low-resolution spectra for the use in isotope identification. Wavelet analysis has the benefit of excellent feature localization while, unlike with Fourier analysis, maintaining the signal frequency and time characteristics. We will demonstrate this technique with a series of gamma-ray spectra obtained from typical hand-held isotope identifiers, illustrate figures-of-merit to be applied to these results, and discuss future algorithm optimization.