Monitoring of air radioactivity at the Jungfraujoch research station: test of a new high volume aerosol sampler.

The Swiss Federal Office of Public Health (SFOPH) is responsible for the surveillance of environmental radioactivity in Switzerland and for the protection of the public from ionizing and non-ionizing radiation. In order to improve the Swiss radioactivity monitoring network, a new high volume air sampler (DIGITEL DHA-80) was tested in Fribourg and at the Jungfraujoch High Altitude Research Station at 3454 m. The filters are analyzed in the laboratory by a high purity coaxial germanium detector. In the test period natural radio nuclides and traces of 137Cs, due to the Chernobyl accident of April 1986, were measured and are in good agreement with values from Germany and Poland. Albeit, the main purpose of this radioactivity monitoring network is to detect rapidly any input of artificial radioactivity, it is also helpful to understand transport of natural radio nuclides in the atmosphere, as for example the cosmogenic 7Be and the long-lived radon daughter 210Pb. The DIGITEL sampler proved to be sufficiently reliable for aerosol radioactivity monitoring even in extreme meteorological conditions at Jungfraujoch. A detection limit for artificial 137Cs of 2 microBq/m3 is obtained.