title: Using gaseous emissions of a proton accelerator facility as tracer for small-scale atmospheric dispersion.
abstract: 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.
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland gernot.butterweck@psi.ch.
authors.forename: G
authors.initials: G
authors.lastname: Butterweck
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: I
authors.initials: I
authors.lastname: Heese
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Hugi
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Züllig
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland Present address: Helmholtz Zentrum München, Munich, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Hödlmoser
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Hohmann
authors.affiliation: Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Mayer
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry*; D003198:Computer Simulation; D017753:Ecosystem; D005740:Gases / Q000032:analysis*; D015233:Models, Statistical; D010315:Particle Accelerators; D011522:Protons; D011834:Radiation Monitoring / Q000379:methods*; D011868:Radioisotopes / Q000032:analysis*; D014919:Wind
chemical_list: D000396:Air Pollutants, Radioactive; D005740:Gases; D011522:Protons; D011868:Radioisotopes