X-ray natural linear dichroism of graphitic materials across the carbon K-edge: Correction for perturbing high-order harmonics

16th International Conference on X-ray Absorption Fine Structure

Jansing, C.^1 ; Mertins, H.C.^1 ; Gaupp, A.^1 ; Sokolov, A.^2 ; Gilbert, M.C.^1 ; Wahab, H.^3 ; Timmers, H.^3

Münster University of Applied Sciences, Physical Engineering, Stegerwaldstraße 39, Steinfurt

48565, Germany^1

Helmholtz-Zentrum Berlin für Materialien und Energie, Albert Einstein Str. 15, Berlin

D-12489, Germany^2

School of Physical, Environmental and Mathematical Sciences, University of New South Wales, PO Box 7916, Canberra BC

ACT

2610, Australia^3

关键词: Adventitious carbon;    Correction techniques;    Graphitic materials;    High order harmonics;    Highly ordered pyrolytic graphites;    Intensity reduction;    Reflectivity measurements;    Synchrotron beamlines;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012031/pdf
DOI  :  10.1088/1742-6596/712/1/012031

来源: IOP

【 摘 要 】

Reflectivity measurements on graphitic materials such as graphene at energies across the carbon K-edge are frustrated by significant intensity loss due to adventitious carbon on beamline mirrors. Such intensity reduction enhances effects due to perturbing high-order harmonics in the beam. These effects distort the actual structure of the reflectance curve. In order to overcome this limitation, a correction technique has been developed and demonstrated first with measurements for highly ordered pyrolytic graphite. The same approach may be applied to other graphitic materials such as graphene and it may be used with other synchrotron beamlines. The fraction of high-order harmonics was determined by passing the incident beam through a 87 nm thin silicon nitride absorber that can be well modeled. Using the corrected measurements the x-ray natural linear dichroism of the sample has been determined.