Fast Mapping : Q&A

The above webinar discusses the capabilities of fast mapping and its applications. Here you can read the Q & A from the webinar for a series of FAQs on the topic of fast mapping.

Q: Do you have to define elemental windows before starting the map?

A: The answer is no. Because you’re getting an entire spectrum from each pixel in the map, you don’t have to define anything ahead of time or after the fact – that’s locked in. You can always go back and change the elements you’ve mapped for, so that way you can dynamically change it as needed. You can even add elements partway through. You can subtract them if you find that they don’t make sense because they shouldn’t be there. But again, if you don’t agree with the spectrometer, you can always check your work by extracting synthesized spectra containing the same elements, and verifying that any decisions that you came to are actually accurate and correct.


Q: Is this method able to be used for polymer or non-metallic materials?

A: The answer is yes. You can certainly use this to look at polymeric materials. As with all SEM work on polymers, you typically have to coat the sample with a conductive coating. Otherwise, you will end up with charging problems because the sample cannot dissipate the charge from the electron beam.


Q: How deep into the sample does the beam penetrate?

A: The beam penetrates anywhere from one up to tens of microns, depending on the density of the material and the energy of your beam. The scale in the webinar example is 10 microns in the lateral dimension, but the same holds true in the vertical direction. Thus, when you’re hitting a low atomic number material like aluminum with a 30 kilovolt beam, most of the information will come from the outermost few microns but you can still get some data from much deeper into the sample surface. So if you’re looking for very sensitive detection, you can still pick up those very weak traces of elements when they’re coming in from a distance. As you can see with the iron comparison, the penetration depth is much smaller because of the higher atomic number of that material. And so you also get a smaller analytical volume with most of the information coming from the top 2 microns. But you can still get some data from as deep as 5 microns, but it’s not the highest intensity data that’s coming from the fringes of those “spot blooms” where the e-beam spreads out into the material.