department of radiation sciences

Research column 1: Environment: Radioecology and Dosimetry

The research of the DRS in this column focuses on three related activities:

  • Security and Safety Research
  • Quantification of Natural Exposures
  • Dosimetry for Epidemiological Cohorts

Examples of research topics in this field:

Radioecological modelling

Radioecological models allow the quantification and analysis of exposures to ionizing radiation due to anthropogenic or natural radionuclides in the environment. Radionuclides may enter the environment by gaseous or liquid discharges from e.g. nuclear or medical facilities. Releases may occur during routine operation or accidental situations. Radionuclides are also released to the environment during mining and milling of uranium. As a new threat the potential effects of a release of radionuclides via the detonation of a „dirty“ bomb have to be considered. Therefore, the analysis of exposures in inhabited areas is of enhanced importance.


Radionuclides in air and deposited material

Measured radionuclides in outdoor air and in deposition samples are analysed in regard to underlying processes (as transport and resuspension) und potential dependences (as on wind and humidity).


Retrospective Dosimetry

Exposition of man to radiation in the past can be detected retrospectively by measuring the absorbed dose in materials of his environment or his body by means of physical methods. The workgroup risk analysis uses and develops the following techniques for dose reconstruction:

  • Electron Paramagnetic Resonance (EPR) of teeth
  • Luminescence (TL/OSL) of building materials, on body worn items and household materials


Retrospective Neutron Dosimetry

The neutron doses of the atomic bomb survivors in Hiroshima and Nagasaki are determined by means of neutron activation measurements. This is important because the cohort of a-bomb survivors provides major input in international efforts to quantify radiation risk and establish radiation safety standards. This includes both radionuclides induced by a-bomb neutrons in environmental materials as well as in tissue samples (tooth enamel) of survivors. The results are compared to calculated neutron fluences published in the literature.


Indoor thoron and radon

Inhalation dose assessment in the indoor environment shall be improved by detailed measurements of the decay products of thoron (220Rn) and radon (222Rn). Inside the new HMGU thoron experimental house, the dependences of the occurrence of thoron are studied and transferred into an indoor model:


Semiconductor sensors for real-time dosimetry






Environmental Dosimetry – Cosmic Radiation

The computer program EPCARD (European Program Package for the Calculation of Air Route Doses) is being developed that allows calculation of air crew doses. The current version of EPCARD is used by many international airlines. These efforts are complemented by measurements of environmental radiation doses from cosmic radiation at mountain altitudes (low atmospheric shielding of cosmic rays compared to sea level) and close to the North Pole (low geomagnetic shielding of cosmic rays).


Computational Dosimetry

Radiation fields often include a variety of different ionising particles, and a complete experimental characterisation of the radiation field is difficult if at all possible. Therefore, different particle transport codes such as GEANT4 and MCNPX are used to simulate complex radiation fields and their interaction with the human body using the most recent ICRP voxel phantoms. This is useful for example for air crew dosimetry, dose estimates after incorporation of radionuclides, dose estimates for neutron therapy at FRMII, and detector development.


Detector Development

In terms of prevention, online information on existing radiation fields is a prerequisite. Thus, a major effiort is to develop small active electronic detectors that allow measurement of radiation exposures in real-time. The familiy of active electronic detectors includes those on neutrons, photons, and radon. Protypes are developed. After successful tests, contacts to industry are established to identify companies that are interested to produce the developed detectors and dosemeters on a commercial basis.


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