There are three contributions to the TEY: photoelectrons, Auger Electrons, and secondary electrons. The secondary electrons will typically determine the maximum depth that you can observe in a TEY measurement. There is a good description of this in Jo Stohr's book, NEXAFS Spectroscopy which can be seen at google books.

At this site, there is a photoelectron spectrum showing the relative intensity of Auger and Photopeaks. The secondaries are roughly a factor of 100 more intense than the other contributions.

It is possible to measure both TEY and Auger electron yield (AEY) and you will see that the AEY is more surface sensitive that TEY. Measuring AEY requires an analyzer capable of discriminating the electron energy. AEY is typically performed at lower photon energies as there are not too many electron energy analyzers at hard x-ray facilities.

It is actually pretty difficult to try to calculate the maximum analysis depth for TEY because of the three different contributions. Here is an attempt to understand the probe depth of TEY but neglects secondary electrons: http://www.icdd.com/resources/axa/vol44/v44_058.pdf

For the K-edges in the hard x-ray regime, with TEY it would not be unrealistic to expect probe depths on the order of 1000 angstroms (100 nm).

On Feb 20, 2008, at 6:33 PM, Jenny Cai wrote:

Hi all,

Could someone please answer my questions? I would really appreciate your help.

1. For linear combination fitting, there are three indicators for the goodness of fitting: R-factor, chi-square and reduced chi-square. Could anyone tell me how they work?

2. Since TEY is sensitive for the surface and FY for the bulk (and surface?), species detected by TEY should be also detected by FY, right?

3. How to calculate the maximum analysis depths for TEY and FY?

Thank you in advance.

Jenny Cai

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