Beryllium-7 concentrations in aerosols during the MOSAiC expedition

Aerosol samples were obtained with a Tisch TE-5170V-BL high volume aerosol sampler, modified to collect 12 replicate samples on acid-washed 47mm diameter Whatman-41 (W-41) filters. The aerosol sampler was mounted on the Polarstern p-deck. Sampling was controlled using wind speed, direction and precipitation sensors (also mounted on the p deck) in order to avoid contamination from ship exhaust. For Be-7 analysis, three of the 47mm aerosol samples were stacked in a plastic Petri dish and counted by gamma spectroscopy. Be-7 has a readily identifiable gamma peak at 478 keV. The counting system was calibrated by preparing a commercial standard in geometry identical to the samples.