Cryo2
Nuclear Stage
Cryo2 has a PrNi5 nuclear demagnetization stage precooled by a model DRP-42 dilution fridge from SHE. If you are wondering what this means, you have not payed attention to our web-site closely enough. We know that life is short and it may be a little too short for you to stare at our web-site all day, but since you have made the effort to come this far, please take some time and look at our web-site a little more carefully. It'll be a great opportunity to learn about ultra low temperature physics. Now, if you have already looked at our web-site inside out and are still going 'what does this mean?', you can contact Johannes Pollanen (j-pollanen@northwestern.edu) or Leo Li (Jiali2015@u.northwestern.edu) and we will be happy to discuss low temperature physics and answer any questions you might have about the work we do.

NMR sample cell and silver heat exchanger for NMR studies on 3He in aerogel.
~10g activated charcoal sorb on Cryo2 still plate. Designed to neutralize a cold leak from the mixing chamber.
Anyway, back to Cryo2. Cryo2 is equipped with a 3.5 Tesla magnet for nuclear magnetic resonance (NMR) experiments at ULT. Specifically, Johannes and Leo are performing NMR experiments to study the properties of superfluid 3He in aerogels with different anisotropy that were grown and characterized right here in our lab. If you want to learn more about aerogel we also have a wonderful section of our site devoted to our work with high porosity silica aerogels, so check it out! Anywho, in the NMR sample cell shown in the picture, there are 3 different kinds of aerogel each having differing types of microstructural anisotropy. From bottom to top we have an isotropic aerogel, an axially compressed aerogel and an intrinsically shrunken aerogel. There are theoretical predictions that different types of anisotropy in aerogel will stabilize different superfluid phases or different order parameter structures of 3He (i.e. textures of the order parameter). Data taking an analysis are currently underway and the results are looking very interesting indeed! Stay tuned to this page and our publication list to find out about all the cool stuff we learn in the next little while about 3He in aerogel.

As of February, 2011, Johannes and Leo are finishing up the measurement and analysis on the radially shrunken aerogel. Leo is currently working on the new NMR sample cell for studying time reversal symmetry breaking in 3He superfluid A phase.

4He 1K Pot

Dilution Fridge

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