Affordable High Sensitivity Radiation Detection using the Correlated Variation Method

Typically improved radiation detection sensitivity is accomplished by increasing the number of detectors. When combining detectors, system sensitivity increases as the square root of the number of detectors. This approach can quickly lead to an unaffordable number of detectors to achieve desired performance. An alternative approach, one in which each signal count is time and detector stamped, is presented here. This additional count data allows for more sophisticated data analysis methods to be applied, allowing discrimination between source and background counts. This approach allows detection of sources with strengths ~10%-20% of that which can be detected by simply summing counts. This approach, called the \"Correlated Variation Method\", is illustrated using a 4 NaI log portal monitor. In Monte Carlo runs this method predicts detection of ?Ci levels of U 235 .