A newly designed compact CEY-XAFS cell in the soft X-ray region and its application to surface XAFS measurements under ambient-pressure conditions without photoinduced side effects.

We report a newly designed compact cell to measure XAFS spectra with the conversion electron yield (CEY) method in the soft X-ray region under ambient-pressure gas conditions. Secondary electrons generated from the gas and sample by collision of X-ray-absorption-induced Auger electrons are collected by a positively biased collector electrode to obtain XAFS spectra. It was confirmed that this cell is applicable to soft X-ray surface XAFS measurements for different types of materials such as insulating organic materials and metal oxides under 1 bar gas conditions. During the measurements, photoinduced side effects were observed; i.e. photoinduced degradation of organic materials and photoinduced reduction/oxidation of metal oxides. We found that these photoinduced side effects can be sufficiently suppressed by controlling the measuring conditions. The presented measuring approach will enable surface XAFS spectra to be obtained in the soft X-ray region for various types of functional materials under ambient-pressure working conditions.