Open AccessPreventing carbon contamination of optical devices for X‐rays: the effect of oxygen on photon‐induced dissociation of CO on platinum
Author(s) -
Risterucci Paul,
Held Geog,
Bendounan Azzedine,
Silly Matthieu G.,
Chauvet Christian,
Pierucci Debora,
Beaulieu Nathan,
Sirotti Fausto
Publication year - 2012
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s090904951202050x
Subject(s) - synchrotron radiation , dissociation (chemistry) , carbon fibers , platinum , x ray photoelectron spectroscopy , oxygen , materials science , contamination , photon , synchrotron , optics , analytical chemistry (journal) , chemistry , nuclear magnetic resonance , physics , environmental chemistry , catalysis , ecology , biochemistry , organic chemistry , composite number , composite material , biology
Platinum is one of the most common coatings used to optimize mirror reflectivity in soft X‐ray beamlines. Normal operation results in optics contamination by carbon‐based molecules present in the residual vacuum of the beamlines. The reflectivity reduction induced by a carbon layer at the mirror surface is a major problem in synchrotron radiation sources. A time‐dependent photoelectron spectroscopy study of the chemical reactions which take place at the Pt(111) surface under operating conditions is presented. It is shown that the carbon contamination layer growth can be stopped and reversed by low partial pressures of oxygen for optics operated in intense photon beams at liquid‐nitrogen temperature. For mirrors operated at room temperature the carbon contamination observed for equivalent partial pressures of CO is reduced and the effects of oxygen are observed on a long time scale.