Friday, May 10, 2019

Table-Top Laser Ablation Unit

I was at the Chicago's Field Museum Members Night last night. Of course, there were lots of fascinating things to see, and wonderful scientists and museum staff to talk to. But inevitably, the experimentalist in me can't stop itself from geeking out over neat gadgets.

This was one such gadget. It is, believe it or not, a table-top laser ablation unit. It is no more bigger than shoe box. I was surprised when I was told what it was, and of course, I wanted to learn more. It appears that this is still a prototype, invented by the smart folks at ETH Zurich (of course!). The scientist at Field Museum uses it to do chemical analysis on trace elements in various objects in the field, where the trace elements are just too minute in quantity that x-ray fluorescence would not be effective.

Now, you have to understand that typically, laser ablation systems tend to occupy whole rooms! It's job is to shoot laser pulses at a target, causing the evaporation of that material. The vapor then typically will migrate to a substrate where it will form a thin film, or coat another object. People use this technique often to make what is known as epitaxial films, where, if suitably chosen, the new film will have the same crystal structure as the substrate, usually up to a certain thickness.

So that was why I was fascinated to see a laser ablation kit that is incredibly small. Granted, they don't need to do lots of ablating. They only need to sample the vapor enough to do elemental analysis. The laser source is commercially bought, but the unit that is in the picture directs the laser to the target, collects the vapor, and then siphon it to a mass spectrometer or something to do its analysis. The whole thing, with the laser and the analyzer, fits on a table top, making it suitable to do remote analysis on items that can't be moved.

And of course, as always, I like to tout of the fact that many of these techniques originate out of physics research, and that eventually, they trickle down to applications elsewhere. But you already know that, don't you?


1 comment:

Douglas Natelson said...

Pretty sure a commercial version is this thing: