MULTICHARME : A NEW CHERNIN TYPE MULTIPASS CELL FOR LONG PATHLENGTH TERAHERTZ SPEC-
TROSCOPY EXPERIMENTS IN AN ATMOSPHERIC SIMULATION CHAMBER.
JEAN DECKER, JONAS BRUCKHUISEN, EIRC FERTEIN, NICOLAS HOUZEL, PIERRE KULINSKI,
ROBIN BOCQUET, FRANCIS HINDLE, GUILLAUME DHONT, GAE¨L MOURET, CE´CILE COEUR,
ARNAUD CUISSET, Laboratoire de Physico-Chimie de l’Atmosphe`re, Universite´ du Littoral Coˆte d’Opale,
Dunkerque, France.
For the first time, THz spectroscopy was used for a direct monitoring of molecular species in the Dunkirk atmospheric
simulation chamber called CHARME for Chamber for the Atmospheric Reactivity and the Metrology of the Environmenta.
Within this chamber, we have developed a specially designed Chernin multi-pass cell ”MULTICHARME” allowing to
adjust a pathlength from 120 m. (24 paths) to 280 m. (56 paths) coupled to a submillimeter wavelength radiation. We
demonstrate the capability to detect and quantify greenhouse gases at trace levels by probing their rotational transitions
close to the Doppler broadening limit. Significant absorbances of 400 ppm residual N2O traces at 577.58 GHz and 200
ppm O3 traces have been measured with a path-length adjusted to 200 meters.b Right now, the accessible detection levels
for both compounds are limited to tens of ppm. We are presently developing a model of the baseline in order to correct
the strong variations caused by multiple interfering stationary waves in the Chernin cell. The first results obtained in
CHARME coupling a THz source to the MultiCHARME Chernin cell opens new possibilities especially for the monitoring
of stratospheric reaction processes at low-pressure. In particular, the versatility of the submillimeter electronic sources
will allow to perform time-resolved quantitative spectroscopies of reactants, oxidants and products involved in targeted
reactions occurring in the high altitude atmospheric layers.
aMeng, L.; Coeur, C.; Fayad, L.; Houzel, N.; Genevray, P.; Bouzidi, H.; Tomas, A.; Chen, W., J. Atmos. Environ., 240, 1117740, 2020.
bCuisset, A.; Hindle, F.; Mouret, G.; Bocquet, R.; Bruckhuisen, J.; Decker, J.; Pienkina, A.; Bray, C.; Fertein, E´.; Boudon, V., Appl. Sci., 11, 1229,
2021.