Category: "Exploding capillaries"

New Capillary Crystal-Growth Device

December 11th, 2014

After several years of planning and several more years of construction, our new crystal-growth device is operational. We are now tuning the electronics, vacuum system, data collection method, and other aspects, but we can indeed produce ice crystals on a glass capillary under controlled conditions.

The thing works!

The first two capillaries we tried basically exploded, due to my having loaded them with way too much water, but the third produced a nice frozen droplet. The frozen droplet, or "droxtal" did not grow on account of all the water that had spewed down from the previous attempts, but we cleaned up the debris, and started anew. That case, pictured above, produced a nice spatial dendrite. I could control the growth condition quite well, and kept growing, sublimating, and regrowing the same crystal for a few days. We now need to refine our capillary-making method and make them about 10x thinner (as I used to do in my previous experiments).

The overall setup is pictured below, Brian at the controls.

The white thing on the right is the cooler. It pumps cold methanol into the big aluminum box sitting on the table. That box is actually three boxes: an innermost crystal box (consisting of several chambers), a bath box that holds the cold methanol cooling fluid, and a vacuum box around that to help insulate the system.

All the controls enter from the top, so we have lots of things sticking up on top: fluid in-out ports, vacuum control of the growth chamber, reference chamber access, access to two vapor-supply chambers plus vacuum control of the chambers, a valve system to connect vapor to growth chambers, and a bunch of wires... The inside of the innermost crystal box is gold-plated to deter corrosion and help us keep contaminants to a minimum.

We hope to have more crystal images soon.