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Comment by cyberax | Hacker News Reader

> If anything this feels like a cost issue not a pure technology issue...

It IS a technology issue. High-TC superconductors are basically ceramics, meaning that they are brittle. And a good simulation of MRI experience is being inside a trash can that other people hit with baseball bats.

We are only now starting to get high-TC superconductors in the form of tape, but it's not yet ready to replace low-TC superconductors.

BTW, it's also the reason we're hearing about so many new fusion startups trying to utilize it. It _should_ provide an order of magnitude cost decreases compared to liquid-helium. But it's still something that only startups are using.

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The largest NMR spectrometer you can buy today uses high-temperature superconductors and classical ones, but it still cools everything down with liquid helium. As far as I understand you can push more current through the high temperature superconductors when you cool them down more.

NMR spectrometers work on essentially the same mechanism as MRIs, just in a very different form factor. It might even work for MRIs without helium because they have a much lower field (~3-6T) compared to the ~28T of the highest field NMR spectrometer.

The high-temperature superconductors are still pretty new for this field, it took a while to figure out manufacturing them on a scale and quality that could be used for these large magnets.

> NMR spectrometers work on essentially the same mechanism as MRIs, just in a very different form factor.

That's a real understatement :)

A typical NMR spectrometer needs to hold a test tube, and an MRI machine kinda has to hold a whole human.

The tape is good enough for fusion reactors but not MRIs?

It's good enough for _startups_ working on fusion reactors, they can tolerate a bit of risk. But not for established companies making safety-critical equipment.

And modern MRI machines are not that expensive either, mass production made them surprisingly affordable. A top-of-the-line machine is around $700k, and mid-range devices are $300-$400k (and now I want one in my backyard...).

So the savings on high-TC supeconductors would not be that impressive overall.

Is 700k the manufacturing cost or a retail price? I thought they were close to 2M on the higher res end.

It's a list price. You'll obviously also need to pay for installation, delivery, and service.

There's apparently even a robust second-hand market for them: https://bimedis.com/search/search-items/magnetic-resonance-i...

People don't go inside a running fusion reactor.

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