PAST DETECTION OF GAMMA-CONTAMINATION

The Natural Background Reduction (NBR) measuring technique based on la rge-volume organic scintillation counter's allows the detection and qu antitative determination of very weak gamma contamination. The measure ment time for detecting an increase in the dose rate by 5 nSv/h typica lly is on the oi der of seconds. The almost complete suppression of na tural background radiation allows especially strongly shielded or remo te radiation sources to be detected much faster and at less expensive than is possible by conventional techniques. Semi-spectroscopic NBR ev aluation, as a method complementing established techniques, helps to u se in situ spectrometers in specific applications or to interpret dose rate data from existing measuring networks.