Peak shift and WS shape

[Rom]

Hi, could you explain, if WS shape and peak position depends of sample nature, why crystal type highly affects on them (WS shape, peak position shift)?
Thank you.

[Probeman]

The terms you are looking for are Bragg's Law, polygonization and Rowland circle.

If I were you I would begin by cracking open some references. The general references in this post should be helpful:

https://smf.probesoftware.com/index.php?topic=343.msg1794#msg1794

[Rom]

I try to read more or less constantly  .
It means peak shift and peak form nature depends of substance but possibility of seen these effects depends of spectral or energy resolution our equipment (crystal type and EPMA machine configuration).
Am I right?

[Probeman]

I try to read more or less constantly  .
It means peak shift and peak form nature depends of substance but possibility of seen these effects depends of spectral or energy resolution our equipment (crystal type and EPMA machine configuration).
Am I right?

The observed peak shift depends primarily on the chemical bond (e.g., oxide, carbide, boride, etc.), and secondarily on the valence and/or coordination. These papers should be read carefully:

G. F. Bastin and H. J. M. Heijligers, "Quantitative Electron Probe Microanalysis of Carbon in Binary Carbides," Parts I
and II, X-Ray Spectr. 15: 135-150, 1986

Bastin, G.F. and Heijligers, H.J.M (1991) Quantitative electron probe microanalysis of ultra-light elements (boron -
oxygen), in Electron Probe Quantitation, ed. K.F.J. Heinrich and D.E. Newbury, Plenum Press, NY, 145-161

Bastin, G.F. and Heijligers, H.J.M. (1992) Present and future of light element analysis with electron beam instruments,
Microbeam Analysis, 1, 61-73.

Armstrong, J.T. (1988) Accurate quantitative analysis of oxygen and nitrogen with a W/Si multi-layer crystal, in D.E.
Newbury, ed., Microbeam Analysis, p. 301-304

Here's a topic that discusses the application of Bastin's area peak factors:

https://smf.probesoftware.com/index.php?topic=536.0

[Rom]

The observed peak shift depends primarily on the chemical bond (e.g., oxide, carbide, boride, etc.), and secondarily on the valence and/or coordination. These papers should be read carefully:

In trying to understand cause of different measurement composition of simple oxides in different standard blocks, I collected WS on MgO (synthetic samples) mounted in 2 different blocks which could have a bit different thickness of carbon coating. I am expecting the difference in not more then 10% around 200A level.

We can see tiny peak shift which leads us to 0.2-0.4wt% uncertainty of Mg in standard samples.
What can be cause of this tiny peak shift - coordination, extrimally tiny contaminations of H2O, O etc., or something else?
It was 1 session, the same conditions of measuring (20 sec on point), different blocks with very close structure (both metal with 2 mm holes for samples)

Thank you.

[Probeman]

It could be slightly different amounts of minor/trace Ca resulting in a small difference in absorption, but I think you need more data points on the peak to be sure.

I suggest tripling the number of data points and using the same (or longer dwell time).