Protection of persons
In addition to radiation protection training, the monitoring of personnel at the FRM II includes equipping them with personal dosimeters, company medical examinations and the incorporation monitoring of FRM II employees.
Annual instruction
When handling radioactive substances, employees may be exposed to radiation from external radiation sources or through the incorporation of radioactive substances. Contamination of the skin, clothing or work objects can also result in external or internal radiation exposure. The aim of the radiation protection instructions is to take appropriate measures to keep any radiation exposure or contamination as low as possible, even below the limit values.
All persons working in radiation protection areas must comply with these radiation protection instructions and follow the instructions of the radiation protection officer. These instructions must also be observed by visiting scientists and external personnel.
Electronic and official dosimeter
An official personal dosimeter is essential for entering the radiation protection control areas. Provided they meet the necessary access requirements, employees receive the so-called albedo neutron dosimeter from Radiation Protection. This personal dosimeter is evaluated monthly by an official evaluation office.
In addition to this official dosimeter, an electronic, directly readable personal dosimeter is worn on the body. This must be activated with the personal employee card. It actively warns the wearer of increased radiation exposure by means of an acoustic signal.
Prevention: Company medical examination
Every occupationally exposed person who is to work under the above-mentioned permit must have been examined by an authorized doctor before starting work. This examination must be repeated annually for persons in category A. There must be no health concerns regarding the handling of radioactive substances. Exceptions to this are those persons who are completing an internship as part of their studies and who can be classified in category B due to the planned activity. In this case, the supervisor must ensure that the limit value for occupationally exposed persons category B cannot be reached.
Hand-foot monitors and whole-body contamination monitors
Contamination measuring devices are used to detect alpha-, beta- or gamma-emitting radioactive substances on surfaces of any kind.
Measuring device for determining personal contamination (surface contamination); the whole-body monitor usually has an arrangement of large-area flow meter tubes that cover almost the entire body surface of the person to be measured. A suitable geometric arrangement ensures that the person is positioned very close to the detector surfaces. This is supported in the so-called two-step monitors by the fact that the measurement takes place in two sections in each of which one half of the body is optimally measured. The head probe is movable and is moved close to the head. The whole-body monitors used on the FRM II also have small parts compartments in which small objects (e.g. ballpoint pens, ID cards, dosimeters) can be checked for contamination. This is done optimally by a combined beta and gamma measurement. An additional incorporation check is sometimes achieved in practice by placing a gamma-sensitive detector (e.g. NaI(Tl) detector) behind the large-area flow meters in the chest area.