Assessing the radiation contamination of large areas using advanced technologies.

Military, disaster management and in many cases civilian tasks include surveying of a given section of terrain that is likely to be contaminated with radioactive materials. Such a measurement series can form the basis for the complete recultivation and decontamination of large areas. This survey can take place after an emergency situation. This paper will use concrete surveys to illustrate the efficiency of new measurement technologies and developments. All these technologies aim to carry out radiation reconnaissance tasks as quickly and accurately as possible. Different hot spots were found during on-foot radiation reconnaissance. During in-situ measurements, a Bayesian-based isotope identifying algorithm was used and the measured data were validated with results from gamma spectroscopy in the laboratory. A rapid on-site quantitative analysis was also performed by evaluating the samples taken next to the hot spots. In addition to the measurement, the data were generated and stored in a standard N42 format ideal for data exchange. Many issues were solved like how the measurement data are associated with relevant additional information (e.g. time and coordinate), and how the measurement results can be shared with other partner organisations. Another important consideration was the preparation of the team conducting the measurement. The total cost of the survey was significantly reduced by the fact that the measurement was manageable by one technician and one expert. A quality assurance system had to be established to meet all relevant standards and strict documentation requirements. In addition to operating at high background radiation, these measurements presented additional challenges due to the low activity of hidden and mixed radioactive sources.