CERNのCLOUD experimentがそろそろ本格始動するようですね。実験による検証こそ科学の一番の醍醐味だと思います。CLOUDチャンバーは大きさとしてはどうなんでしょう。大気を再現するには小さいと見るべきか、微量分析が出来るなら十分と見るべきか。
The arrival of the CLOUD chamber
http://cdsweb.cern.ch/record/1181089?ln=bg
CLOUDを提案したJasper Kirkbyのインタビューが載せてあるブログがありますので紹介します。
The Reference Frame: CERN: CLOUD experiment began operation
http://motls.blogspot.com/2009/11/cern-cloud-experiment-began-operation.html
ちなみに、スベンスマルクの本「The Chilling Stars」は邦訳が出版されるようです。
“不機嫌な”太陽―気候変動のもうひとつのシナリオ: H スベンスマルク, N コールター, 桜井邦朋, 青山洋
http://www.amazon.co.jp/dp/4769912137/
1.The CLOUD proposal to CERN: A study of the link between cosmic rays and clouds with a cloud chamber at the CERN PS, CERN-SPSC-2000-021, SPSC-P317 (24 April 2000).
http://cloud.web.cern.ch/cloud/documents_cloud/cloud_proposal.pdf
2.First addendum to the CLOUD proposal: Addendum to the CLOUD proposal, CERN-SPSC-2000-030, SPSC-P317 Add.1 (4 August 2000).
http://cloud.web.cern.ch/cloud/documents_cloud/cloud_addendum.pdf
3.Second addendum to the CLOUD proposal: CLOUD: an atmospheric research facility at CERN, CERN/SPSC 2000-041, SPSC/P317 Add.2 (17 October 2000).
http://cloud.web.cern.ch/cloud/documents_cloud/cloud_addendum_2.pdf
4.Memo to the CLOUD proposal: CERN Proposal SPSC/P317; the CLOUD experiment , CERN-SPSC-2004-023, SPSC-M-721 (13 August 2004).
http://cloud.web.cern.ch/cloud/documents_cloud/cloud_memo.pdf
5.Third addendum to the CLOUD proposal: Initial CLOUD resources & schedule , CERN-SPSC-2006-004, SPSC-P317 Add.3 (20 January 2006).
http://cloud.web.cern.ch/cloud/documents_cloud/cloud_addendum_3.pdf
Workshop on Ion-Aerosol-Cloud Interactions, CERN (18-20 April 2001).
http://cloud.web.cern.ch/cloud/iaci_workshop/index.html
Details of the CLOUD experiment: CLOUD: a particle beam facility to investigate the influence of cosmic rays on clouds, in Proc. of the Workshop on Ion-Aerosol-Cloud Interactions, ed. J. Kirkby, CERN, Geneva, CERN 2001-007 (2001).
http://cloud.web.cern.ch/cloud/documents_cloud/kirkby_iaci.pdf
Original CLOUD concept: Beam measurements of a CLOUD (Cosmics Leaving OUtdoor Droplets) chamber, 24 February 1998, CERN-OPEN-2001-028.
http://cloud.web.cern.ch/cloud/documents_cloud/cloud_concept.pdf
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3.3 Experimental programme
Experiments in 2009 will be carried out near 20℃ in a stable temperature environment provided by a high-precision temperature control system and chamber insulation. Then, in the 2009–2010 winter shutdown, the temperature range will be extended to the full range of tropospheric and stratospheric temperatures (-90℃ to +30℃). This provides a very important experimental capability which is unavailable at most of the existing aerosol chambers and other nucleation research facilities (e.g. the Caltech aerosol chamber, the PSI aerosol chamber, the J¨ulich aerosol chamber and the Laminar Flow Reactor at IfT Leipzig can only be operated at ambient temperatures). Furthermore, beginning in 2010, the chamber will have the capability to act as a “cloud chamber” by making fast adiabatic pressure drops of up 100 mbar in 5 s and activating cloud droplets and ice particles.
The first two series of experiments are foreseen as:
1. 1st physics run (Sep–Nov 2009): study of ion induced nucleation (IIN) for various H2SO4, H2O, and ion concentrations at room temperature; comparison with neutral nucleation conditions.
2. 2nd physics run (Spring 2010): IIN for various H2SO4, H2O and ion concentrations at variable temperatures and with NH3 or volatile organic compounds (VOCs) as additional parameters.
An important part of these early measurements will be to characterise the technical performance of the CLOUD-09 chamber in areas such as background contaminants, temperature stability, reproducibility of aerosol burst measurements, trace gas lifetimes, etc.
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The global impact of a simulated change in the nucleation rate on atmospheric aerosol
(page.16)
は少々興味深いことが書いてあるような気がするかも。
−−−−−(一部引用)
Metzger et al. (2010) found that a nucleation
rate of the form J = k [H2SO4]m ×[NucOrg]n produced
better agreement with observations. Combining this
kinetic mechanism with the findings of the CLOUD
2009 experiment, we will suggest upper bounds for
the impact of the enhancement in nucleation caused by
ions on condensation nuclei, cloud condensation
nuclei and cloud droplet number concentration.
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