Print View Posted on: 02 September 2026
On 27 July 2026, an employee performed a Gamma radiography measurement using a Se-75 source with an activity of 1.48 TBq. After completing the measurement, the employee inadvertently failed to retract the source into its safety position in a shieled container. Subsequently, he carried out activities in the vicinity of the source for up to four minutes at an approximate distance of 50 cm before noticing that the radioactive source had not been returned into the container. As the employee’s electronic radiation protection dosimeter had been switched off, no warning alarm was triggered. The exposure situation was such that the official dosimeter was shielded and consequently showed an unrealistic low reading. Therefore, the effective whole-body dose was calculated based on the exposure situation and was estimated to be between 27 and 32 mSv. This dose exceeds the statutory annual whole body dose limit for occupationally exposed workers.