USING GASEOUS EMISSIONS OF A PROTON ACCELERATOR FACILITY AS TRACER FOR SMALL-SCALE ATMOSPHERIC DISPERSION
| Autor: | Sabine Mayer, I. Heese, H. Hödlmoser, J. Züllig, E. Hohmann, R. Hugi, G. Butterweck |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Complex topography
Scale (ratio) Wind law.invention Nuclear magnetic resonance Stack (abstract data type) law Radiation Monitoring TRACER Radiology Nuclear Medicine and imaging Computer Simulation Ecosystem Radioisotopes Radiation Models Statistical Radiological and Ultrasound Technology Atmosphere Public Health Environmental and Occupational Health Particle accelerator General Medicine Atmospheric dispersion modeling Wind direction Computational physics Air Pollutants Radioactive Environmental science Gases Particle Accelerators Protons Dispersion (chemistry) |
| Popis: | The gaseous effluents of the proton accelerator facility located in the Western part of the Paul Scherrer Institute, Aargau, Switzerland, contain a mixture of positron emitters (50 % (15)O, 20 % (13)N and 30 % (11)C). For the experimental verification of a future upgrade of the dispersion model in the complex topography of the Aare valley, a measuring campaign using three continuous gamma-spectrometric measuring stations was launched in 2011. The concept of a modified man-made-gross-count (MMGC) ratio yields a clear signal associated with the positron emitters while minimising the influence of radon progeny rain-out events. A dependence of the measured MMGC ratios on the emitted activity and wind direction could be demonstrated using frequency distributions of the modified MMGC ratio measured in 2012 and 2013. A significant fraction of high MMGC-ratio values was found associated with dispersion directions (based on measurements of the wind direction in 70 m above ground) not towards or even against the direction between stack and measuring station. |
| Databáze: | OpenAIRE |
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