1. Beamline AILES : Mid IR to THz Spectroscopy The AILES Infrared and THz High Resolution Spectroscopy beamline at SOLEIL (Saclay, 30 km south of Paris) – LISA CNRS-Université Paris Est A new Low temperature long path gas cell for Mid IR to THz spectroscopy with Synchrotron Radiation Soleil: L. Lago, M. Chapuis, F. Willaert, L. Manceron, P. Roy LISA: F. Kwabia Tchana, X. Landsheere, JM Flaud

2. 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.

3. Beamline AILES : Mid IR to THz Spectroscopy Optics: Classical White Configuration Limitations for FIR-THz… Instead : Chernin Configuration

4. Beamline AILES : Mid IR to THz Spectroscopy In short: UHV design, base pressure 5.10 -8 mbar after bake-out, Ionic Pumping : vibration-free Objectives : Accurate far infrared high resolution spectra of diluted gas samples and mixture at temperatures : 400 - 100K Adapted optics for long path (<150m in Far IR, ) Four compartments chamber : Sample gas Convection-cooling gas (He) Liquid Nitrogen reservoir Insulating vacuum 1m

5. Beamline AILES : Mid IR to THz Spectroscopy

6. Optics, temperature sensors,heaters In operation coupled to the IFS 125… Diamond windows, viewports

7. Beamline AILES : Mid IR to THz Spectroscopy Temperature… adjustable, regulated from 400 to 80K

8. Beamline AILES : Mid IR to THz Spectroscopy Optical path from 3 to 141m Linearity of detection

9. Beamline AILES : Mid IR to THz Spectroscopy 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! Home made precision Capacitive gauge for operation down to 77K Principle : measurement of thin metal membrane deflection by a capacitive sensor designed for low temperature 100 µm Inconel membrane electrodes GAS Vacuum …and Pressure

10. Beamline AILES : Mid IR to THz Spectroscopy Some examples : C 3 H 8 : HR measurements in the 7 to 30 µm At low temperature for line by line analysis SF 6 : Observation of the υ 6 IR and R -forbidden band See talk RI08 V. Boudon….

11. Beamline AILES : Mid IR to THz Spectroscopy Or lower in the far IR… CH 4 Distorsion- induced rotational spectrum at Low T SF 6 : Observation of weak difference bands (here υ 3- υ 1)

12. 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