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Does anyone know why these apparatuses are usually "inverted", i.e. hang from the ceiling. I've seen the same thing for quantum computers. Is it related to the

Does anyone know why these apparatuses are usually "inverted", i.e. hang from the ceiling. I've seen the same thing for quantum computers. Is it related to the way they are cooled? Or is it easier to work with somehow?

oasisbob 9y ago
Swinging wild-ass guess - it might because it makes it easier to damp the equipment against vibrations. The STM in a surface chemistry lab I worked in for a while was inside a box, and hanging from the roof of the box. By choosing appropriate springs to hang the sensitive bits from and sound proofing the box, it could adequately isolate the scanning table from its environment.
pohl 9y ago
I'm sharing this prior to reading it: https://en.m.wikipedia.org/wiki/Dilution_refrigerator https://en.m.wikipedia.org/wiki/Dilution_refrigerator
- VLM 9y ago
  The Germans working on the same problem are running at 100 mK aka 0.1 K, so pretty chilly yes http://iopscience.iop.org/article/10.1088/1681-7575/54/1/S1/pdf http://iopscience.iop.org/article/10.1088/1681-7575/54/1/S1/...
- miduil 9y ago
  Thank you for sharing. I've started searching for "dilution refrigerator" and found this video, explaining a little bit how ³He–⁴He mixture cooling works and what the applications are. I think the video also helps putting the Wikipedia article in a perspective and vice versa. Quantum Cooling to (Near) Absolute Zero (2013): https://www.youtube.com/watch?v=7jT5rbE69ho https://www.youtube.com/watch?v=7jT5rbE69ho
marcosdumay 9y ago
One thing that I know is that it is easier to dump vibrations by hanging your device with springs than by supporting it above springs. But I don't think this is relevant here. EDIT: Yeah, pohl answered it. Vibrations are not relevant.
- SolarNet 9y ago
  If you read the article he posted the cooling mechanism is very susceptible to vibrations, which is why they suspend it.
deleted 9y ago
[deleted]
tacon 9y ago
The entire apparatus sits in a cryostat (a fancy Thermos bottle) which is filled with liquid helium. In general, one supports things in liquid baths from above.
gaze 9y ago
It's because in a dilution refrigerator, the bottom of the dilution unit gets cold. So its easier to put the coldest part at the bottom.

oasisbob 9y ago

Swinging wild-ass guess - it might because it makes it easier to damp the equipment against vibrations. The STM in a surface chemistry lab I worked in for a while was inside a box, and hanging from the roof of the box. By choosing appropriate springs to hang the sensitive bits from and sound proofing the box, it could adequately isolate the scanning table from its environment.

pohl 9y ago

I'm sharing this prior to reading it: https://en.m.wikipedia.org/wiki/Dilution_refrigerator https://en.m.wikipedia.org/wiki/Dilution_refrigerator

VLM 9y ago
The Germans working on the same problem are running at 100 mK aka 0.1 K, so pretty chilly yes http://iopscience.iop.org/article/10.1088/1681-7575/54/1/S1/pdf http://iopscience.iop.org/article/10.1088/1681-7575/54/1/S1/...
miduil 9y ago
Thank you for sharing. I've started searching for "dilution refrigerator" and found this video, explaining a little bit how ³He–⁴He mixture cooling works and what the applications are. I think the video also helps putting the Wikipedia article in a perspective and vice versa. Quantum Cooling to (Near) Absolute Zero (2013): https://www.youtube.com/watch?v=7jT5rbE69ho https://www.youtube.com/watch?v=7jT5rbE69ho

marcosdumay 9y ago

One thing that I know is that it is easier to dump vibrations by hanging your device with springs than by supporting it above springs. But I don't think this is relevant here. EDIT: Yeah, pohl answered it. Vibrations are not relevant.

SolarNet 9y ago
If you read the article he posted the cooling mechanism is very susceptible to vibrations, which is why they suspend it.

deleted 9y ago

[deleted]

tacon 9y ago

The entire apparatus sits in a cryostat (a fancy Thermos bottle) which is filled with liquid helium. In general, one supports things in liquid baths from above.

gaze 9y ago

It's because in a dilution refrigerator, the bottom of the dilution unit gets cold. So its easier to put the coldest part at the bottom.