Quantification of enviromental exposures
- Fig 1: Measurement shed
Measurement of secondary neutrons from cosmic radiation at mountain altitudes
A Bonner multi-sphere spectrometer has been installed in 2005 at the Environmental Research Station “Schneefernerhaus” (2,660 m above sea level) on the Zugspitze mountain, Germany, to measure the energy spectrum of cosmic ray neutrons at high altitudes continuously (Figs. 1 and 2). The spectrometer consists of 16 3He proportional counters. Thirteen counters are covered by polyethylene shells with various thicknesses, while two are covered by polyethylene shells including lead, to increase the response to neutrons above 20 MeV (Fig. 3). Because the count rate at such high altitudes is about a factor of 5 larger than at sea level, the system can be used to investigate small temporal variations in the cosmic radiation intensity. For example, measurements were performed during periods of 2 Forbush decreases in July and September 2005, respectively, of the cosmic radiation intensity.
- Fig 2: Enviromental research station
- Fig 3: Bonner sphere spectrometer
Press release (20. Oct 2005, in German)
Enviromental research station "Schneefernerhaus" (UFS)
The NMDB Neutron Monitor Data Base
Recently, the data obtained on the Environmental Research Station “Schneefernerhaus” (UFS) with the Bonner multi-sphere spectrometer system have been included in the real-time database for high resolution neutron monitor measurements (NMDB).
Neutron Monitor Database (NMDB)
References:
W. Rühm, V. Mares, C. Pioch, G. Simmer and E. Weitzenegger. Continuous measurement of secondary neutrons from cosmic radiation at mountain altitudes and close to the North Pole-A Discussion in terms of H*(10). Radiation Protection Dosimetry (2009), Vol. 136, No. 4, pp. 256-261.
W. Rühm, V. Mares, C. Pioch, E. Weitzenegger, H.G. Paretzke. Continuous Measurement of Secondary Neutrons from Cosmic Radiation at Low Atmospheric and Geomagnetic Shielding by Means of Bonner sphere spectrometers. Proceeding of 21stEuropean Cosmic Ray Symposium, 9 - 12 September 2008, Kosice, Slovakia.
G. Leuthold, V. Mares, W. Rühm, E. Weitzenegger, H.G. Paretzke. Long-term measurements of cosmic ray neutrons by means of a Bonner spectrometer at mountain altitudes – first results. Radiation Protection Dosimetry, Vol. 126, No. 1-4, pp. 506-511, 2007.