On-peak interferences

[Dan MacDonald]

Good afternoon, everyone:

I am just starting to make a relatively complex file and have a basic question about on-peak interference corrections.  What is the best way to handle these corrections? Is it really as simple as going to Standard Assignments, then clicking on the element of interest, then selecting the interfering element in Assignment properties and finally picking the Interference Standard?  Thank you very much in advance for your kind help.

Kind regards

Dan MacDonald
Probe Tech
Dalhousie University
Halifax, N.S.

[Probeman]

I am just starting to make a relatively complex file and have a basic question about on-peak interference corrections.  What is the best way to handle these corrections? Is it really as simple as going to Standard Assignments, then clicking on the element of interest, then selecting the interfering element in Assignment properties and finally picking the Interference Standard?  Thank you very much in advance for your kind help.

Hi Dan,
Yes, it really is that simple! 

The only caveat is that one needs a standard for the interference correction which does not contain any of the interfered element, and which contains a known amount of the interfering element (generally the larger the better), and which also does not contain any other interfering elements (for the interfered element in question).

I usually first click the Calculate Interferences button to see whether the interference in question is even possible. It's just a nominal gaussian overlap calculation, but better than nothing.

See this topic for a brief overview and do let us know if you have any questions or concerns:

http://probesoftware.com/smf/index.php?topic=69.0

Note that the maximum number of interferences per element was recently increased from 5 to 6.
john

[Dan MacDonald]

Good afternoon, everyone:

I have a small question about interference standards.  Do they have to be the same material/standard as the primary standard used for the interfering element?  For example, I have a rutile (TiO2) with traces of V in it (0.42 wt % V2O3) that I use as my primary standard for Ti.  For V, I use V metal as the primary standard.  Can I use Ti metal as my interference standard when correcting for the Ti Kb overlap on the V Ka peak? (I ask bec the old JEOL software I was used to only allowed for the interference standard to be the primary standard for the interfering element). Thanks very much for all your kind help.

Best regards

Dan MacDonald
Probe Tech

[Probeman]

I have a small question about interference standards.  Do they have to be the same material/standard as the primary standard used for the interfering element?  For example, I have a rutile (TiO2) with traces of V in it (0.42 wt % V2O3) that I use as my primary standard for Ti.  For V, I use V metal as the primary standard.  Can I use Ti metal as my interference standard when correcting for the Ti Kb overlap on the V Ka peak? (I ask bec the old JEOL software I was used to only allowed for the interference standard to be the primary standard for the interfering element).

Hi Dan,
In Probe for EPMA, the primary standard for the interfering element and the standard utilized for the interference correction can be the same or they can be different. All the matrix correction differences between them and the unknown are automatically handled.

So long as the criteria I mentioned in the previous post are adhered to. That is, you cannot use a standard for the Ti interference on V which contains any of the interfered element, in this case V.  If you do, you will get a "double correction".

So you can use pure Ti or TiO2 as your primary Ti standard, and you can also use Ti or TiO2 as your interference standard for Ti on V, but the interference standard for Ti on V *cannot* contain any V.

But note that many published papers report small amounts of V in rutile that are almost always due to the interference of Ti Kb on V Ka.  As the bumper sticker on my office door says: "don't believe everything you think"!   
john