Charging of aerosol particles - An investigation of the possibility of using Americium-241 for SMPS chargers

Sammanfattning: Climate change is a fact and effects everybody on this planet, whether its humans, plants or animals. There is a comprehensive agreement about the mechanisms on how aerosol particles affect the radiative balance of the earth, but there is a need of more knowledge to fully understand climate change and the strength of the aerosol radiative forcing. The aim of this thesis is to investigate if the SMPS system can use a charger based on the radioactive substance Americium-241 (241Am), which can be found in disposed smoke detectors, and which emits α-particles. To perform the measurements, an SMPS system was used without and with different chargers to test the performance of the α-charger whereas the Ni-charger and Kr-charger are used for validation of the α-charger. Four different configurations were tried with varying number of Am-sources (3, 7, 9, and 15). The measurements showed no consistent and reproducible behavior of aerosol charging with the α-charger. The conclusions of this thesis are that there is a need of more controlled measurements with nebulized aerosol particles and with a different setup keeping track of the charging state of aerosol particles as described in the discussion section. Keywords: SMPS, aerosol particles, Americium-241, climate change, particle number size distribution.