The main component of the natural exposure of humans to ionizing radiation is the inhalation of ephemeral progenies of the radioactive rare gas "radon" which occurs in the earth's atmosphere in the form of the two nuclides Rn-222 and Rn-220. In epidemiological studies it is assumed that in the Federal Republic of Germany, approx. 5% of all lung cancer cases must be attributed to the inhalation of...

In a cooperation with different institutes, a measurement method and a detector system for the determination of the cross section of carbon combustion to oxygen are used, which allow the physical processes shortly before supernova explosions to be investigated.

For the generation of a reference atmosphere, ten Th-228 sources from which Rn-220 emanates were installed in the thoron progenies chamber. Each single source is located in a drawer in a lead cube. Opening and closing of the drawers with the sources inside is controlled from the outside via a source control system. If a source is immersed in the lead cube, this serves to shield the ionizing...

When measuring systems are calibrated in the thoron progenies chamber it must be ensured that the generated reference atmosphere is homogeneous with respect to the individual activity concentrations. However, a homogeneous distribution of Rn-220 is not that easy to ensure as this isotope has a half-life of only 55 s. This is why Rn-220 is supplied to the atmosphere via the source control system in...

Neutron spectrometry in plasma diagnosis requires complex data analysis procedures. A method which combines the procedures of the Bayes’s statistics and the maximum entropy allows parameters to be investigated which describe the plasma in fusion experiments.

A TDCR apparatus was constructed for determining activity with the aid of the liquid scintillation technique which supplements the existing method for determining activity and opens up new possibilities for calibration, also for nuclides with complex decay schemes.

At the heavy ion facility GSI in Darmstadt, Germany, a special form of radiotherapy is carried out which uses a high-energy carbon ion beam to destroy the tumour. The ion beam is thereby directed very precisely onto the whole tumour volume by means of the so-called raster-scanning method. To date, there exists no suitable primary standard for the determination of the absorbed dose to water for...

It was possible to determine with a standard measurement uncertainty of only 0.3% the relative response of the secondary standard measuring system based on the detection of radiation-induced free radicals in alanine for ultrahard photon radiation at 8 MV and 16 MV as used in radiotherapy. The measuring system is therefore applicable within the scope of examinations in therapeutically relevant...

The intercomparison was performed to investigate the long-term behaviour of H*(10) dosemeters dedicated to the monitoring of nuclear plants and facilities in the radiation field of the natural ambient radiation. After two years of measuring time, the intercomparison was completed in autumn 2007. First results are now available. The area dosemeters were supplied by ten participating institutions...

For the permanent measurement of radiation exposure on board commercial aircrafts, the handy measuring device NAVIDOS has been developed within the scope of the RAMONA project which was funded by the Federal Ministry of Transport, Building and Urban Affairs (BMVBS).

In cooperation with DLR, PTB takes part in radioprotection measurements on board the International Space Station (ISS), and in the development of a direct reading personal dose equivalent meter for astronauts.

More than 50% of the effective collective dose due to X-ray diagnostics in the population is caused by computer tomography (CT) so that the determination of the effective patient dose within the scope of CT examinations is of great significance. Department 6.6 has therefore thoroughly investigated the methods used for the calibration of CT ionisation chambers. They thereby found out that the...

The 2nd intercomparison in the field of trace analysis of radioactive materials in air close to the ground was carried out by the Co-ordinating Office for Trace Analysis at the Federal Office for Radioprotection in cooperation with PTB. Offices for trace analysis from Germany, Austria and Switzerland took part in the intercomparison. This intercomparison allowed the participants to assess their...

In the field of radioprotection, globalisation has been taking place for several years already. Thereby, one important control instrument is standardisation, which has been realised also at European level since 2001. New milestones are the IEC/EN 61526 standards for direct reading personal dose (electronic) equivalent meters and monitors and its counterpart, IEC 62387, for passive dosimeters. From...

For the type testing of dosemeters by means of photon radiation, a large number of reference radiation fields are necessary - among others, a field with high-energy photons with a mean photon energy of 4.4 MeV or 6.7 MeV.

For this high-energy photon field, a new measuring facility is used in which both commercially available measuring instruments as well as this department's own developments are...

Monte Carlo simulations describe the dependence of the Relative Biological Effectiveness of photon radiation with energies smaller than 1 MeV; for larger energies, there are indications of new mechanisms of effectiveness.

By the simulation of ionization cluster-size formation in a nanometric target volume, it is shown for electrons and light ions that the frequency to form at least two ionization events is directly proportional to radio-biological cross sections. The measurement of nanodosimetric frequency distributions for the characterization of beam qualities is, therefore, regarded as the future method for...

Die ideal elastischen Materialeigenschaften von einkristallinem Silizium machen dieses Material interessant für den Einsatz in Präzisionswaagen. Ein erster Wägezellen-Federkörper aus einkristallinem Silizium mit einer Nennlast von 6 kg wurde in der PTB entwickelt und gefertigt. Hierbei stellen das spröde Materialverhalten von Silizium und die zu realisierenden, 1 mm dicken Dünnstellen eine...

Zur Geschwindigkeitsmessung von kleinen Weltraumpartikeln wurde ein Messaufbau entwickelt, der den beim Durchflug durch eine Laserlichtebene entstehenden Lichtblitz detektiert. Erste Funktionstests mit schnellen Miniaturgeschossen wurden erfolgreich absolviert. Der Messaufbau ermöglicht durch Detektion und Auswertung einzelner Lichtblitze auch die Untersuchung von Geschossgarben.

With the precision force transducers used so far, the force is measured in an axis predefined by the transducer construction. In the last few years, however, the demand for force transducers working with similar precision in all spatial axes (force vector transducers) has increased. In addition, torques shall be measured in the different axes. Now, corresponding transducers and - at PTB -...