For anyone that has used a Talos S/TEM with a large liquid nitrogen dewar attached, how do you fill your tank? The inside of the microscope is very cramped, and it is awkward to pour the liquid nitrogen from a transfer vessel into the dewar. We have been looking at purchasing a 10-20 L dewar fitted with a withdrawal device and hose attachment so we can transfer the liquid nitrogen directly from a large dewar into the microscope's dewar. I'm curious if there are any other solutions I'm overlooking.
If this helps anyone, here was the solution we came up with.
We ordered the following parts from a liquid nitrogen supply vendor:
- 20 L Al container for storing liquid nitrogen (LN2)
- Siphon head for transferring liquid nitrogen (LN2 transfer valve, vent valve, manometer, 0.5 bar overpressure value, clamp, O-ring with centering ring, screw adapter)
- Roller base
- LN2 transfer hose with PTFE piping and phase separator
Once the 20 L container is out of LN2, we vent it, take off the siphon head, insert a transfer hose from a large LN2 container, and fill our 20 L container nearly to the top. We let the metal at the opening warm a bit and then attach the siphon head. We move it into our TEM lab so that it can build up pressure overnight. Then, we simply insert the transfer hose on our container into the dewar on the microscope, and the pressure pushes it up the hose. We only have to do this refilling process about once a week.
Here is a video showing the overall procedure: https://youtu.be/zrCT433gaK0?si=0jMnaafOOavsEepc
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