Date of Award


Document Type


Degree Name

Master of Science (MS)

Legacy Department

Environmental Engineering and Science


DeVol, Timothy


The on-line monitoring for illicit radioactive material with a minimum number of false detections is a critical need for homeland security. The primary objectives of this work were to apply both Bayesian and classical statistical process control chart techniques to the on-line monitoring of radiological data and to then compare the Type I and Type II error incidence rates. Two versions of the cumulative sum (CUSUM) and Shiryayev-Roberts (S-R) procedures known as total reset and alarm reset methods were developed. The best method in terms of Type I errors was the S-R total reset method. In terms of Type II errors, the CUSUM alarm reset procedure and the S-R alarm reset control scheme were most effective. At high count rates, the Shewhart (3-sigma) control chart resulted in the fewest number of false negatives independent of the amount of time a source was present.