CLOUD experiment
Duplissy Jonathan
Detector seminar, 2010 October 22nd
Layout of the talk
1) Introduction to atmospheric particle2) CLOUD chamber3) Detectors
1) Introduction
Indian monsoon & Cosmic rays9500 to 6500 years ago
Neff et al., Nature 411, 2001
North Atlantic ice rafted debris
Bond et al., Science 294, 2001
Aerosol definition
Definition of an aerosol:
Suspension of small (liquid or solid)
particles in a gas
Primary aerosol:
Directly emitted into the atmosphere
Secondary aerosol:
Formed into the atmosphere
(aerosol directly emitted into the atmosphere)
Sea spray Volcano ► Sulfates, dustMineral dust
Biomass burning ►OrganicsTraffic emissions ► Soot
Primary aerosol
Pollen: 10 - 100 μm
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
Zhang et al, science 328, 2010
Secondary aerosolaerosol is formed in the atmosphere
Influence of the galactic cosmic ray via the ionization of the molecule?
Example of Nucleation in a
control enviroment
Observation of ions and nucleation
Hirsikko, ACPD 10, 2010
Radiative forcing
Figure adapted from IPCC report 2005, full figure available on IPCC report
An
thro
po
gen
icN
atu
ral
Leve
l of scie
ntific u
nd
erstan
din
g
Direct Aerosol effect
Scattering and absorption of solar radiation
Indirect aerosol effect
Large droplets Weak reflection
Shorter life-time (rain)
Small droplets
Strong reflection Longer life-time
Steven & Feingold, nature 461 ,2009
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/
Effect of particles on clouds:Contrails
Aerosol composition
Jimenez et al, science 326, 2009
2) Chamber
Smog chamberEnvironmental chamberCloud chamber
Smog chamber principle
• Do a control experiment:
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
http://www.ceam.es/
Outdoor smog chamber
http://saphir.fz-juelich.de
Saphir, Jülich, Germany, 2000. Size: 270 m3
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 chamberTemperature ranging from -90°C to +50°CPressure ranging from 0.1 to 1000hPa
AIDA chamber, Karlsruhe, Germany, 1997. Size: 85 m3
http://www.eurochamp.org/chambers/aida/
Location of CLOUD at CERN
CLOUD in PS-T11
28
PS East Hall, Building 157
T11 beam area (3.5 GeV/c)
CLOUD chamber
Gas supply: Air, water, traces
Fan
Fan
Chamber
Exhaust
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
CLOUD chamber
Gas supply: Air, water, traces
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
Gas supply: Air, water, traces
Detectors
Fan
Fan
UV light fiber
Chamber
Exhaust
~27 m³, cleanliness to the highest standards (stainless steel, ceramic)
state-of-the-art detectors (gas phase, ions, particles)
CLOUD chamber
Gas supply: Air, water, traces
Detectors
Fan
Fan
UV light fiber
Chamber
IONS
Exhaust
hodoscope
PS Beam3.5 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
Gas supply: Air, water, traces
Detectors
Fan
Fan
UV light fiber
Chamber
Exhaust
HV Field cage
HV Field cagehodoscope
PS Beam3.5 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
Gas supply: Air, water, traces
Detectors
Fan
Fan
UV light fiber
Chamber
Exhaust
HV Field cage
HV Field cagehodoscope
PS Beam3.5 Gev Pi+
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
35
• 27 m3
• Pressure: Atmospheric ± 0.3 bar• Only metallic seals• Electropolished inner surfaces
UV are brought to the chambervia optic fiber
- Control of the UV intensity- No heat load from the light
Light system
Light system
UV seen from the bottom
2 * 30 kVolts
Field cage
Mixing Fans
Gas supply: Air, water, traces
Fan
Fan
Chamber
Exhaust
Two mixing fans
Mixing fan
41
CLOUD chamber Temperature
Gas supply: Air, water, traces
Fan
Fan
Chamber
Exhaust
excellent thermal stability (±0.01°C), temperature ranges from -25°C to 100°C
Detectors
Thermal unit
CLOUD isolation
Isolated feet
CLOUD isolation
Temperature stability
More than 40 temperature sensors around the chamber
Temperature stability
47
• 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%
Tinternal
3h 20min record
2.8oC
2.9oC
2.4oC
2.7oC
2.6oC
2.5oC
16 electropolished sampling probes
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
UV
CERN clean and demineralized water
Dry pure air
Air saturated with water to the CLOUD chamber
Temperature controlled
Permapure
Particle filter
Particle filter
Organic filter
Organic filter
Ionsfilter
Very clean water with less than 3 ppb of organic, but still too much…
CLOUD installation
February 2009
CLOUD installation
53Caillebotis #!&?... November 2009!
July 2009 September 2009
CLOUD ready for technicalrun in December 2009
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)
• Switzerland (Paul Scherrer Institute, CERN)
• United Kingdom (University of Leeds)
• 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
• DewPoint
Beam
• Hodoscope
Particles counters
• Nano-SMPS
• CCNC
• CPC battery
• PSM
Ions counters
• NAIS
• Gerdien
CLOUD collaboration
10 Marie Curie fellows5 more PhD students5 more master students30 seniors scientificsAll great CERN teams
Aerosols nucleation
PS Beam,Hodoscope
API-tof-MS, PTRMS (VOC)
CIMS DewPointNAIS, Gerdien
CPC, SMPS, Snapper, AMS
CCNC, HTDMA
AIS principle
Bigger size
IonsAir flow (60 l/min)
Electrometer
High voltage
The AIS measures the ions distribution
Time
Aerosol inlet
Negative column
Positive column
Main power source, 15V
output
Electrometers’ output
signal collectors
Stabilized voltage units
for analyzers
Electrometers 1 ( at top) to 21
Electrometers 22 (at top) to 42
Pictures from: A.I.S. manual
AIS principle
PTR-MS
H2O
H2O+
O+
H+
OH+
H3O+
H3O+
H3O+
H3O+
VOC
VOC•H+e–
H3O+
H3O+
H3O+
Proton transfer
reaction when
PA(VOC)>PA(H2O)
H3O+ + VOC → VOCH+ + H2O pseudo first-order kineticsk
tkOHi
VOCHi
1
)(
)( VOC
3
PTR-MS How does it work?
PTR Drift Tube TOF-MS
Pulser Detector
Inlet
System Description: PTR-TOFMS
Time of Flight
Sign
al
Aquisition
Timing
Identification:
• Peak Separation
• Exact Mass Measurement
• Isotopic Ratio
HR-ToF-AMS
Inlet
Heater
ToF Mass Spectrometer
Filament
V-Mode
W-Mode
DeCarlo et al., Anal Chem (2006)
High Resolution comparison
DeCarlo et al., Anal. Chem (2006)
Atmospheric Pressure Interface Time Of Flight mass spectrometer
reflector
detector
10-6 mbar
10-4 mbar
10-3 mbar
2 mbar
3-stage turbo
scroll500 l/min
1 mbar
1 mbar
API-TOF scheme
Condensation Particle Counter
Buthanol CPC principle
CPC detection efficiency
Differential mobility analyser (DMA)
SMPS
Neutralizer DMA CPC
Known equilibrium charged of the particle
Select one size of the particle
Count the number of particle
SMPS provides size distribution of the particles
Results: fireworks at CLOUD
Thank you
Acknowledgement
Funding:
- EC's Seventh Framework Programme (Marie Curie Initial Training Network "CLOUD - ITN")
- German Federal Ministry of Education and Research
- Swiss National Science Foundation
- Academy of Finland Center of Excellence
- CERN
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