Vibration Isolation of Precision Objects (2005) [pdf]

lanthade 12/28/2025|

Back 30 odd years ago I was doing work with a graduate/post graduate chem-e/material science group at the U of MN. I was working with a PhD candidate who was working on synthetic insulin. Part of the project was attempting to use a scanning tunneling microscope (STM) to image insulin at the molecular level. I hadn't ever done work with STM before and part of showing proficiency with the tool was to image Highly Oriented Pyrolytic Graphite (HOPG) at the molecular level. As you can imagine almost any vibration will show up when you're working on the scale where you measure in angstroms.

To solve for the vibration issue the STM lab was in the basement of the building and the STM equipment sat on a multi-ton granite block that was suspended from the ceiling of the building. The building sits in the center of the U of MN campus right next to a major roadway so there were lots of opportunities for vibrations to enter into the structure.

One of the coolest feelings was the day that I successfully imaged HOPG at the molecular level. To point at the image on screen and be able to say "That's a carbon atom!" is insanely cool. I didn't end up staying in chem-e but the experience of working in a real research lab with highly intelligent and creative people has impacted my life in numerous ways.

lioeters 12/29/2025|

> multi-ton granite block .. suspended from the ceiling of the building

That's fun to imagine. I've heard of vibration isolation for machines, using springs and such, but this is on a whole another scale. Sounds like the building must be designed for it specifically to withstand this kind of pull.

And to be able to take an image of an individual atom, what an experience.

lanthade 12/29/2025||

Yeah I have no idea how they pulled off the structural piece. The building was built long before the technology was invented. It is a specialized building though. I was reading about its renovation/expansion in 2014. Apparently there are a couple 2 story labs to accommodate large distillation columns and there was additional vibration isolation work done because there's now a light rail train running right outside it.

Speaking of interesting building design, the chemistry building on the same campus was designed to channel any lab explosions upward. Apparently the roof will blow off but the building won't blow out and damage other buildings around it. Inside the building you die, outside you keep walking to class.

Scene_Cast2 12/28/2025|

Tangentially related - I was doing some highly sensitive analog electronics work. It's surprisingly hard to find capacitors that don't exhibit microphonic behavior - i.e. they don't produce (miniature) voltage swings when you tap the PCB.