Fluorescent Dye in Petrographic Thin Sections

[jtmitchell]

Hi everyone,

I have a user scheduled to do some work in my lab in a week or so, and they've used a fluorescent dye in the epoxy to help them view fractures. This isn't something I do or have come across before, so I was wondering if anyone has worked on samples like this and, if so, is there anything I need to be aware of once they're in the probe?

Thank you!

[Jens Andersen]

I've known of operators that have outright banned dyed specimens from claims that they have contaminated the sample chamber, so be careful.

Things I'd consider are;
1. Is the dye outgassing under vacuum in the carbon coater? Monitor the pressure gauge while pumping down. If it is, can the outgassing be stabilised? If not, dismiss the samples.
2. Is it stable under the electron beam? Might it release any contaminants or harmful substances? Try to do a quick EDS on a spot of resin. Are there any signals coming up?

If in doubt, always minimise beam intensity and residence time on the dyed resin. I'd avoid mapping if the map extends to ablate the resin.