Ionising Radiation at Radar Facilities

For some years contributions about radiation exposures at radar facilities or radar devices of the German armed forces were published in the German media. A lot of Soldiers or other specialised workers who dealt with these devices before 1975 claimed their diseases as been caused by the radiation. In most of the cases and the resulting reports it is not distinguished between the high frequency radiation and the ionising radiation caused by the electron tubes like Klystrons, Thyratrons or other valves. This paper is limited to the ionising radiation. An overview about the technical basis of the emission of ionising radiation is given. The radiation is pulsed, the energy is often very low and additional in the field of high frequency radiation it is not trivial to measure the ionising radiation by the common electronic radiation measurement devices. The authors decided to use thermoluminescent dosimeters. Two selected measurements, one at a military radar system from the sixties and one at a contemporary civil airport surveillance radar system will be presented. The presented results from the military radar system show, that there could had been large radiation exposures: in the chosen example a dose rate up to 3.5 mGy per hour. But it will also be discussed that this would lead in most cases only to a skin dose, taking the very low energy into account. On the other side, it could be verified, that contemporary civil surveillance radar systems do not emit considerable radiation exposure for the technicians, who are working on these machines and of course not for other people which stay nearby the radar systems.