Helmholtz Zentrum München

German Research Centre for Environmental Health

Bonner Vielkugelspektrometer zum Nachweis sekundärer Neutronen

Institute of Radiation Protection

The housing of the Bonner Spheres Spectrometer including 16 Proportional Counters.
The housing of the Bonner Spheres Spectrometer including 16 Proportional Counters.

Cosmic Radiation

The UFS Schneefernerhaus is the only research station at mountain altitudes worldwide that includes a Bonner spheres spectrometer, to monitor secondary neutrons from cosmic radiation. The spectrometer was installed in 2005 by the Institute of Radiation Protection of the HMGU, and complemented by a second spectrometer that was installed in 2007 at the Koldewey Station on Spitzbergen. Together, these spectrometers allow continuous measurements of both the intensity of secondary neutrons from cosmic radiation and their energy distribution, at low atmospheric shielding (UFS) and low geomagnetic shielding (Koldewey Station). The measurement results are used to validate energy spectra of cosmic ray particles calculated by means of Monte Carlo methods, at any location and height in the atmosphere and at any time within the normal 11-years cycle of sun activity. With the spectrometer, changes in cosmic radiation during large solar mass ejections (solar storms) will also be quantified. Exact knowledge of the energy distribution of the particles from secondary cosmic radiation in the atmosphere is required to investigate their influence on ion production in the atmosphere which might contribute to global cloud formation. The field of secondary cosmic radiation is also used to calculate doses to pilots and cabin crew.

realtime data:

Continuous cosmic ray measurements for Zugspitze mountain, Germany, cutoff=4,1 GV

Environmental Radioactivity - Radioecology in the case of snow

In the past, radioecology mainly focused on the vegetation period to quantify direct contamination paths of vegetation and soil after the release of radio nuclides. Radioecological processes related to snow are investigated to a lesser extent and many problems are not yet understood. Therefore, deposition on and with snow will be studied as well as the melting process with its partition in melting water and residuum. Different winter scenarios for the behavior of the radio nuclides in space and time for rural and urban environs will be defined and studied in detail. Prognosis of larger scale contamination and strategies for decontamination and mitigation will be developed. Deposition measurements on and with snow will be performed by gamma-spectrometry for the reference nuclides Be-7, Na-22, Pb-210 and Cs-137 at present homogeneously distributed environmental concentrations. It is assumed that washout of radio nuclides by snow is more effective than by rain. In intense measurement periods a high level of parameterization of the deposition process is aspired: particle size distribution, characterization of snow flakes, etc. The melting process will be studied with environmental nuclides in the field. In laboratory studies these may be amended by artificial nuclides.

Department of Environmental Sciences - Molecular Exposomics /Cooperation Group Comprehensive Molecular Analytics

POP collectors on the platform of the research station.
POP collectors on the platform of the research station.

The Alps act as a sink for organic pollutants (POPs) due to the barrier effect and the phenomenon of cold condensation. There is an altitudinal increase of concentration of POPs (e.g. pesticides) in Alpine ecosystems mainly because precipitation increases and degradation from soils decreases with altitude. Nevertheless concentrations in the air in remote regions are very low and the measurements pose heavy challenges for instrumentation and analytical procedures.
In the framework of the EU Interreg III (Alpine Space) MONARPOP project, high and low volume samplers have been installed at Schneefernerhaus in order to monitor different POP species in dependence of their source regions. Atmospheric concentrations of various substances are so low that active air samplers have to operate several days to collect detectable amounts. Due to the fact that in the Alps information about the possible source region cannot be given by using the current wind direction a forecast of possible trajectories has to be performed every day. By relaying the incoming airflow among an array of four filters the air is sampled accordingly to four source regions. Similar measurements are performed at Weißfluhjoch (Switzerland) and Sonnblick (Austria).
After three years in the MONARPOP project (2005-2008), in which HMGU collaborated with several partners like the UBA Vienna, both monitoring and scientific programmes continued in cooperation with the Bavarian Environment Agency as POPALP (2008-2010) and EMPOP (2012-2013). The programmes are supported by the Bavarian State Ministry of the Environment and Public Health (BayStMUG).

Contact
Dr. Gert Jakobi
Helmholtz Zentrum München
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Tel. +49 89 3187-3145
Fax +49 89 3187-3371

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Dr. Manfred Kirchner
Helmholtz Zentrum München
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Tel. +49 89-3187-4116
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Prof. Dr. Werner Rühm
Helmholtz Zentrum München
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Tel. +49 89 3187-2460
Fax +49 89 3187-3323

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Dr. Jochen Tschiersch
Helmholtz Zentrum München
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Tel. +49 89 3187-2763


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Most recently modified: March 2013