The aim of this task is to evaluate and validate the performance of three different radioactivity mapping systems based on gamma, alpha and dose emissions. Validation takes place in nuclear decommissioning sites or simulated nuclear environments.

The gamma mapping system consists of a GAMPIX camera which will be validated on its quantitative performance on the spectrometric mode of the camera and the quantitative performance with new pixelated chips available (Timepix 3, CALISTE HD). The validation will be performed with mono and multi-gamma radioactive sources in an energy range between 60 keV to 2600 keV, to determine a complete uncertainty budget.


Gampix Gamma Camera


Mapping of Gamma emmitters in situ measurements


The capability of the alpha mapping technique will be validated using a pre-production model, engineered for use in contaminated environments. The optimization of usability and data visualization will also be a central role in this activity. The target sensitivity of the alpha mapping system at 1 m distance is 10 kBq under UV-free lighting (50 lux), and 1 MBq under normal lighting (200 lux). The spatial resolution will be similar to conventional surface contamination probes. The performance will be tested at NNL’s central laboratories using open alpha sources in the activity range from less than 1 kBq up to 100 MBq.


UV based stand-off mapping alpha-emitters


A system for real-time dose-rate mapping will be developed. The system will consist of a large number of cheap compact radiation detectors, linked wirelessly to a central computer. In addition to establishing a calibration method, software will be developed to create dose maps with a low uncertainty (due to the large number of detectors used). The optimum sampling points for the detectors will be studied, taking into account Bayesian statistics if appropriate