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Quality assurance of early-warning dosimetry systems

23.12.2021

A novel photon irradiation facility that provides reference fields for the harmonization of early‑warning dosimetry systems has been successfully tested and put into operation. This system will also be used for ensuring a uniform federal quality standard in accordance with the German Radiation Protection Ordinance (StrlSchV § 103).

The irradiation facility for environmental dosimetry (see left Figure) was developed to increase the dose rate at a reference site in the environment by up to a factor of five using a number of different sealed radioactive sources. This enables the thorough investigation of early‑warning dosimetry systems under real‑world conditions with regard to their ability to detect radiological emergencies.

The radiation sources of the irradiation facility can be moved from a shielded magazine to various irradiation positions located in the middle of lead cylinders of various thicknesses, resulting in different dose rates due to the different attenuation levels involved. The entire procedure of moving the different sources to different irradiation positions is controlled by a newly developed computer program (right Figure). This software makes it possible to specify various time‑dependent dose rate profiles. In addition, it is ensured that in case of malfunction the sources will be secured in a shielded magazine.

The aim of experimentally simulating a radioactive cloud (airborne contamination) is to check and examine the response behavior of detector systems to gamma radiation as it would occur in a radiological event. A particular challenge is to quickly and reliably detect small unnatural changes of the ambient dose equivalent rate. The participants of the measurement comparisons include representatives of measurement bodies in Europe, from industry, research institutions and national metrology institutes.

Irradiation facility and program user interface

Figure on the left: Photo of the irradiation facility. Figure on the right: The user interface of the newly developed program to operate the irradiation facility.

Contacts

Opens local program for sending emailF. Krasniqi, Department 6.3, Working Group 6.32

Opens local program for sending emailJ. Roth, Department 6.3, Working Group 6.35

Opens local program for sending emailB. Lambertsen, Department 6.3, Working Group 6.35