Detecting ever lower amounts of ionising radiation with ever better methods sci-entists have had this goal since the start of the nuclear age. In addition to natural radiation, mankind is exposed to a multitude of other sources of radiation which result from the military and technical use of radioactive substances. To protect health, but also for technical and medical applications, it is necessary to determine even the smallest amounts of radionuclides with high precision. On the invitation of the Physikalisch-Technische Bundesanstalt (PTB), scientists from 27 countries are meeting from 22nd to 26th September 2008 to exchange ideas about new measurement and analytical techniques and possible ways of applying them: at the "5th International Conference on Radionuclide Metrology Low-Level Radioactivity Measurement Techniques".
PTB scientists contribute to this international exchange with three dissertations:
1. The German thoron progeny chamber Concept and Application
Abstract: For the measurement of the thoron progenies, a reference field has been estab-lished within the scope of a project funded by the Federal Ministry of Environment, Nature Protection Reactor Safety. This field consists of an air-conditioned walk-in testing chamber in which the environmental parameters temperature, air humidity and aerosol content can be adjusted and controlled. Analogue to the radon reference chamber, Carnauba wax aerosol is used as model aerosol. The activity concentrations of thoron and of the thoron progenies shall be adjusted by means of several open exhalation sources with 228Th which are distrib-uted in the chamber. Homogeneity of the environmental parameters and of the activity con-centrations of thoron and its progenies in the chamber is ensured by a special ventilation system. With this system, a compromise has been made between high circulation rates due to the low half-life of thoron, on the one hand, and low flow velocities due t
|Contact: Dr. Dirk Arnold|
Physikalisch-Technische Bundesanstalt (PTB)