XUtils

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XUtils>System>NiOxIceC

Current Function Version: 0.5 (June/25/'09)

Brief Description
This function determines the accumulated ice and carbon thicknesses from two X-ray spectra measured with a certain interval (e.g. a few months) from Ray Egerton's NiOx thin film test specimen. The detail descriptions about the NiOx test specimen can be found in the original papers by Ray Egerton and his co-workers, which are summarized in the previous description for the NiOx plug-in. The brief procedure to determine the accumulated ice and carbon thicknesses is also found in later Results section.

Usage
Open two X-ray spectra measured from the NiOx thin film in Gatan DigitalMicrograph. These spectra must be acquired in the same instrument in almost identical experimental conditions with a few month interval. Again, you can import the spectra using the EMSA file import plug-in. Select XUtils>System>NiOxIceC from the menu bar, and following dialog appears.

First, click the Select Spectra button and a sub-dialog called "Select two NiOx spectra" appears. In this sub-dialog, you should select two spectra indivisually.

It is recommended to select an older spectrum as Image 0. Otherwise, you may see negative values in layer thicknesses (unless your detector window is self-cleaned!). Then, click OK. The selected spectra should be loaded.

Finally, just click the the Calculate button.

Results
Here is a typical result.

For determination of the ice and carbon layer thicknesses, following equations can be used:

The unit of the thickness is in nm. These equations are similar to the original equations proposed by Wong and Egerton but the pre-factors in front of the intensity ratio are different. This difference is caused by employing slightly difference values of the mass absorption coefficients and densities.

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