Use of Wavelet Denoising in Identifying Radioactive Isotopes Using a Gamma-Ray Spectrum

Radiation Isotope Identification Devices (RIID) are used in homeland security and other applications to identify radioactive materials. RIIDs have trouble automatically identifying radioisotopes accurately and robustly, which leads to both false positive and false negative alarms. Expert spectroscopists are often called to resolve difficult-to-resolve alarms. Spectroscopists are estimated to correctly resolve ~90% of such alarms. A study of the four most commonly used commercial RIID detectors found that the overall “correct” identification value in a laboratory setting was 39%. False positive identifications occurred 44% of the time and false negative identifications occurred 10% of the time. The current study shows that RIID accuracy can be significantly improved by using a spectrum denoising signal processing step based on a wavelet shrinkage method.