Exploring NIST

Thursday we were back at it with the tours, this time at NIST. Luis had done a great job organizing everything and I had a lot of fun learning about everything they do. For those who don't know (and it's ok if you don't), NIST stands for National Institute of Standards and Technology. It's actually an agency that's under the jurisdiction of my committee (fun fact), and they do a variety of basic research projects and create standards for all kinds of things. They're tasked with keeping track of, say, the meter in the U.S., and they are currently trying to find a fundamental way to describe the kilogram (rather than the hunk of metal in Paris, which is what we have now).

We're all in front of a descendant of the apple tree that (supposedly) inspired Isaac Newton.

Here's something interesting they do:

These are jars labeled, among other things, "peanut butter", "meat homogenate", and "domestic sludge" (aka "sewage"). Essentially, NIST gets samples-- doesn't really matter where, could be straight from the store-- and measures certain relevant quantities, like trans fat or sulfur. Industries can then purchase these certified samples from the agency, along with their score card, and run it through their own testing equipment. If the numbers come out the same as those on the score card, everything's good. If not, maybe they need to re-calibrate.

They have standard colors too!

My favorite lab that we visited was one devoted to Bose-Einstein condensates. These are gases of bosons that are cooled to very low temperatures (just above absolute zero), where quantum phenomena become apparent at the macroscopic level. In English, they're really cold things that are weird as hell.

The grad student who was working in the lab showed us all the cooling equipment they use to create these BECs. The first line of defense is a laser-cooling mechanism, which takes advantage of three basic physics principles: doppler shifts, electromagnetic absorption, and the fact that a photon can impart momentum. Essentially, a laser at very specific wavelengths is shone at the gas, and only atoms that are in motion absorb the photons, which slows them down. This technique can get them to a few Kelvin, but that's not good enough for a BEC.

The next step is evaporative cooling. This exactly like when you blow on your soup to cool it down; you're getting rid of the high energy (=high temperature) molecules that have "escaped" the liquid. You see, if you plot the likelihood of finding a molecule at a given speed, it looks something like this:

Notice the "tails" at the end of each of these distributions. These represent the very few high-speed (again, = high temperature) molecules. If you remove these molecules, "cutting off" the tails, the peak of the function will shift to a lower speed, indicating that the gas as a whole has reached a lower temperature.

The amazing thing is that in the lab they're able to get to about 300 nanoKelvin. That is 0.0000003 Kelvin-- and nothing can get below 0 Kelvin. Incredible. Also, I got a shot of the equipment so you can see how much fun it must have been to put it together.

Next we visited the robotic testing facilities. Since the field is so new, there aren't really any standard tests to measure a robot's capabilities, so the consumer basically just has to trust the manufacturer that it works, mostly. NIST is trying to develop a system based on 80-85, which is an assurance that it works with 85% certainty 80% of the time (or maybe the other way around, I don't remember). Here are some of the tests they're working on:

This is for drones, etc. It's got visual tests (targets, QR codes, etc) and fans to simulate wind. They can also make it "rain" to be absolutely sure the robot works in the real world.

The gap between the two boards can be changed to simulate a variety of conditions.

The field can be adjusted for different inclinations, and they also have a variety of materials available.

Our final lab stop was the Center for Neutron Research, where the director was thrilled to show us around. He was also in SPS back in college, and he had way too much fun asking us questions about physics. When we asked if photos were allowed, he cheerfully replied "Technically you need administrative permission, but I can give you that so go for it!"

I'll admit, a good bit of the nuclear/neutron stuff went over my head, but it was still really cool to see all of the projects they're working on.