CLOUD experiment - CERN

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Transcript of CLOUD experiment - CERN

CLOUD experimentLayout of the talk
1) Introduction to atmospheric particle 2) CLOUD chamber 3) Detectors
1) Introduction
Neff et al., Nature 411, 2001
North Atlantic ice rafted debris
Bond et al., Science 294, 2001
Aerosol definition
particles in a gas
Secondary aerosol:
Biomass burning OrganicsTraffic emissions Soot
Primary aerosol
Diesel soot: ca. 0.1 μm Ammonium sulfate: ca. 0.1 μm
Sea salt: 0.2 - 10 μm Mineral dust: 0.2 - 10 μm
Primary aerosol example
Secondary aerosol aerosol is formed in the atmosphere
Influence of the galactic cosmic ray via the ionization of the molecule?
Example of Nucleation in a
control enviroment
Hirsikko, ACPD 10, 2010
Radiative forcing
Figure adapted from IPCC report 2005, full figure available on IPCC report
A n
th ro
p o
ge n
ic N
at u
ra l
Le ve
Indirect aerosol effect
Effect of particles on clouds: Ship tracks
Ship tracks on the East Atlantic Aerosol particles emitted by ships (soot
particles with a high sulfur content) act
as cloud condensation nuclei and form
clouds and enhance cloud reflectivity
France
Spain
http://visibleearth.nasa.gov/
Aerosol composition
2) Chamber
Smog chamber principle
1) Inject gas inside a chamber
2) Start reaction by ozonolysis (adding Ozone) or photo-chemistry (switching the light)
3) Measure the gas evolution and particle formation
(compare to flow tube experiment, smog chamber has longer residence time)
Outdoor smog chamber
The University of North Carolina Outdoor Smog Chamber, U.S.A. in operation since 1971
Fox et al, science 1976
Euphore, Valencia, Spain, 1995. Size: 200 m3
Outdoor smog chamber
Outdoor smog chamber
Stockholm University outdoor smog chamber, in a boreal forest environment , 2010
Indoor smog chamber
PSI’s smog chamber, Villigen, Switzerland, 2002. Size: 27 m3
Kalberer et al, science, 2004;Metzger et al, PNAS, 2010
Indoor smog chamber
AIDA chamber
85 m3 aluminum chamber Temperature ranging from -90°C to +50°C Pressure ranging from 0.1 to 1000hPa
AIDA chamber, Karlsruhe, Germany, 1997. Size: 85 m3
http://www.eurochamp.org/chambers/aida/
CLOUD in PS-T11
CLOUD chamber
Fan
Fan
Chamber
Exhaust
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
CLOUD chamber
Detectors
Fan
Fan
Chamber
Exhaust
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
state-of-the-art detectors (gas phase, ions, particles)
CLOUD chamber
Detectors
Fan
Fan
Chamber
Exhaust
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
state-of-the-art detectors (gas phase, ions, particles)
CLOUD chamber
Detectors
Fan
Fan
PS Beam 3.5 Gev Pi+
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
state-of-the-art instruments (gas phase, ions, particles)
ions at different concentrations created from CERN PS beam
CLOUD chamber
Detectors
Fan
Fan
PS Beam 3.5 Gev Pi+
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
state-of-the-art instruments (gas phase, ions, particles)
ions at different concentrations created from CERN PS beam
natural ions can be removed by HV field cage (~1s lifetime)
CLOUD chamber
Detectors
Fan
Fan
Thermal unit
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
state-of-the-art instruments (gas phase, ions, particles)
ions at different concentrations created from CERN PS beam
natural ions can be removed by HV field cage (~1s lifetime)
excellent thermal stability (±0.01°C), temperatures from -25°C to 100°C
CLOUD Aerosol chamber
• Pressure: Atmospheric ± 0.3 bar • Only metallic seals • Electropolished inner surfaces
UV are brought to the chamber via optic fiber
- Control of the UV intensity - No heat load from the light
Light system
Light system
2 * 30 kVolts
Fan
Fan
Chamber
Exhaust
Fan
Fan
Chamber
Exhaust
excellent thermal stability (±0.01°C), temperature ranges from -25°C to 100°C
Detectors
Temperature stability
• Chamber walls & internal temperature stable to ~0.01oC over long periods
• No temperature change when UV lights turned on at 100%
• No T-induced nucleations were observed during entire campaign
UV on at 100%
Sampling probes
CLOUD chamber
Air supply
• Ultra-pure air is made from the mixture of liquid nitrogen and liquid oxygen
• SO2 and other traces gas are in very clean gas mixture bottles
• Ozone is produced by UV light system
Humidification System
Dry pure air
Temperature controlled
Particle filter
Particle filter
Organic filter
Organic filter
Ions filter
Very clean water with less than 3 ppb of organic, but still too much…
CLOUD installation
February 2009
CLOUD installation
54
CLOUD
Detectors brought by: • Austria (University of Innsbruck, University of Vienna)
• Finland (University of Helsinki, Finish Meteorological Institute, University of Eastern Finland)
• Germany (Goethe University of Frankfurt, IfT Leipzig)
• Portugal (University of Lisbon)
• Russia (Lebedev Physical Institute)
• USA (CALTEC)
3) Detectors
Mass Spectrometers
• Api-tof-MS (ions)
• PTR-tof-MS (Organic)
• CI-MS (H2SO4)
• PTR-MS (NH3)
Gas Detectors
• O3 analyzers
• SO2 analyzers
• NH3 analyzers
CLOUD collaboration
10 Marie Curie fellows 5 more PhD students 5 more master students 30 seniors scientifics All great CERN teams
Aerosols nucleation
Electrometer
Time
Pictures from: A.I.S. manual
tkOHi
VOCHi
1
PTR Drift Tube TOF-MS
High Resolution comparison
Atmospheric Pressure Interface Time Of Flight mass spectrometer
reflector
detector
Count the number of particle
SMPS provides size distribution of the particles
Results: fireworks at CLOUD
- EC's Seventh Framework Programme (Marie Curie Initial Training Network "CLOUD - ITN")
- German Federal Ministry of Education and Research
- Swiss National Science Foundation
- CERN