Transcript Cryocell-Columbus-Symposium-2013.pptx

Beamline AILES : Mid IR to THz Spectroscopy
A new Low temperature long path gas cell
for Mid IR to THz spectroscopy with
Synchrotron Radiation
The AILES Infrared and THz High Resolution Spectroscopy beamline at
SOLEIL (Saclay, 30 km south of Paris) – LISA CNRS-Université Paris Est
Soleil: L. Lago, M. Chapuis, F. Willaert, L. Manceron, P. Roy
LISA: F. Kwabia Tchana, X. Landsheere, JM Flaud
Beamline AILES : Mid IR to THz Spectroscopy
AILES = Beamline on Synchrotron SOLEIL and Experimental
Station with High Resolution Interferometer (0.001 cm-1 max.)
Open User facility for the Molecular Spectroscopy Community
for Broad Band Absorption Spectroscopy in the mid to Far Infrared
Specifications for a long path cell :
-Variable optical path : 3 to ~150m. Spectral range 4000 to 10 cm-1
-Temperature adjustable in the 100 to 400K range, homogeneity
and control within ±1K.
-Pressure 1000 to 0.1 mb, measured with ±2%.
-Resistance to mildly corrosive compounds.
-Optical Transmission ≥ 10%. Diamond windows → HR mirrors.
-Mechanical stability (vibration free pumping) optical stability.
-Rapid adjustment of optical path length.
Beamline AILES : Mid IR to THz Spectroscopy
Optics:
Classical White Configuration
Limitations for FIR-THz…
Instead : Chernin Configuration
Beamline AILES : Mid IR to THz Spectroscopy
Objectives : Accurate far infrared high resolution spectra of diluted gas samples and mixture
at temperatures : 400 - 100K
Four compartments chamber :
•Sample gas
•Convection-cooling gas (He)
•Liquid Nitrogen reservoir
•Insulating vacuum
Adapted optics for long path (<150m in Far IR, )
In short: UHV design , base pressure 5.10-8 mbar after bake-out, Ionic Pumping : vibration-free
Beamline AILES : Mid IR to THz Spectroscopy
Beamline AILES : Mid IR to THz Spectroscopy
Optics,
temperature sensors,heaters
Diamond windows,
viewports
In operation coupled to the IFS 125…
Beamline AILES : Mid IR to THz Spectroscopy
Temperature… adjustable, regulated from 400 to 80K
(1)
(2)
(3)
(4)
(5)
0
Temperature (°C)
-50
20.4 (0.2)
0.9 (0.8)
- 31.0(0.5)
- 48.7 (1.2)
- 64.2 (1.2)
-103.0 (0.6)
-146 (2.5)
-167 (1.5)
- 189 (5)
-100
-150
-200
Folded optical path domain
-250
0
20
40
60
80 100 120 140 160 180
Position along cell axis (cm)
Beamline AILES : Mid IR to THz Spectroscopy
Optical path from 3 to 141m
Linearity of detection
Beamline AILES : Mid IR to THz Spectroscopy
…and Pressure
For intensity measurements of
low Vapor Pressure Volatile Organic Compounds:
Need for precise Pressure in the 0.01-100 mbar range
No cryogenic gauge commercially available!
Principle :
measurement of thin metal membrane deflection
by a capacitive sensor
designed for low temperature
GAS
Deflexion at center (in µm)
Home made precision Capacitive gauge for operation down to 77K
40
30
20
10
0
0
10
20
30
Pressure (mb)
Vacuum
Précision relative (%)
10
electrodes
1
100 µm Inconel
membrane
0,1
0,01
0,1
1
Pression (mbar)
10
40
50
Beamline AILES : Mid IR to THz Spectroscopy
Some examples :
C3H8 :
HR measurements in the 7 to 30 µm
At low temperature for line by line
analysis
SF6 : Observation of the υ6
IR and R -forbidden band
See talk RI08 V. Boudon….
Transmission
(a)
(b)
Beamline AILES : Mid IR to THz Spectroscopy
Or lower in the far IR…
SF6 : Observation of weak
difference bands (here υ3- υ1)
CH4
Distorsion- induced
rotational spectrum
at Low T
Beamline AILES : Mid IR to THz Spectroscopy
SOLEIL: Open User Facility ,
contact beamline scientists if interested…
Two important WEB Pages :
• http://www.synchrotron-soleil.fr/
For general informations, how to contact us…
and, for proposal submissions :
• http://sunset.synchrotron-soleil.fr/sun/
• twice a year , mid-september and –february deadlines. Proposals
(submissions in English) ranked by an international peer–review
committee.
• How to submit your proposals
• Support from User Office
• Preparing your experiment
• Safety requirements