TY  - JOUR
A1  - Duplissy, Jonathan
A1  - Enghoff, Martin Bødker
A1  - Aplin, Karen L.
A1  - Arnold, Frank
A1  - Aufmhoff, Heinfried
A1  - Avngaard, Michael
A1  - Baltensperger, Urs
A1  - Bondo, Torsten
A1  - Bingham, Robert
A1  - Carslaw, Kenneth S.
A1  - Curtius, Joachim
A1  - David, André
A1  - Fastrup, Bent
A1  - Gagné, Stéphanie
A1  - Hahn, F.
A1  - Harrison, R. Giles
A1  - Kellett, Barry
A1  - Kirkby, Jasper
A1  - Kulmala, Markku
A1  - Laakso, Lauri
A1  - Laaksonen, Ari
A1  - Lillestol, Egil
A1  - Lockwood, Michael
A1  - Mäkelä, Jyrki
A1  - Makhmutov, Vladimir
A1  - Marsh, Nigel D.
A1  - Nieminen, Tuomo
A1  - Onnela, Antti
A1  - Pedersen, E.
A1  - Pedersen, Jens Olaf Pepke
A1  - Polny, Josef
A1  - Reichl, Ulrike
A1  - Seinfeld, John H.
A1  - Sipilä, Mikko
A1  - Stozhkov, Yuri
A1  - Stratmann, Frank
A1  - Svensmark, Henrik
A1  - Svensmark, J.
A1  - Veenhof, Rob
A1  - Verheggen, Bart
A1  - Viisanen, Yrjö
A1  - Wagner, Paul E.
A1  - Wehrle, Günther
A1  - Weingartner, Ernest
A1  - Wex, Heike
A1  - Wilhelmsson, Mats
A1  - Winkler, Paul M.
T1  - Results from the CERN pilot CLOUD experiment
T2  - Atmospheric chemistry and physics / Discussions, 9.2009, S. 18235-18270
N2  - During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the CLOUD1 experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2SO4 concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1°C).
Y1  - 2009
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/29247
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-292476
SN  - 1680-7367
SN  - 1680-7375
N1  - © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License.
VL  - 9
SP  - 18235
EP  - 18270
PB  - European Geosciences Union
CY  - Katlenburg-Lindau
ER  -