[vhfpmr (OP)]

It seems the Koreans have just discovered the Holy Grail:
https://arxiv.org/abs/2307.12008
https://arxiv.org/ftp/arxiv/papers/2307/2307.12008.pdf

[alancalverd]

The paper is sufficiently convincing to tempt me back into the world of MRI magnet design!

[Bored chemist]

I might postpone selling some dead lead-acid batteries to the scrap dealer.

What amuses me is that this material consists of elements that have been available for 350 years or so.

[paul cotter]

I hope this does not lead to garage tinkerers trying emulate such technology: as I am sure you know p4 is exceedingly dangerous with an ld50 of ~50mg. Obviously polymerised p such as red p is fairly innocuous but if heating is required I for one sure won't be near it.   Late correction: silly me, I should have read the paper before my premature comment, it is p as phosphate, totally safe. However with the lead content the eu might try to ban it, they have a severely misplaced fear of lead.

[paul cotter]

I am surprised that a substance which is basically a doped lead phosphate even conducts at all. I know that βpbo2 is an excellent conductor in the massive state having used home made electrodeposited pbo2 in anodic oxidation( perchlorate ), but a phosphate salt? Mri scanners with superconducting magnets must require a lot of maintenance with their dual cryogenics and a room temperature superconductor would be a major boon: the only downside is that it may recall Alancalverd from retirement and this would be a great loss to the forum!

[alancalverd]

Far from retired - this is the coffee room in my one-man office!

MRI maintenance actually involves very little to do with the cryogens. I used to own a couple of upright MRIs, one with a room-temperature electromagnet and one that used recirculating helium gas with a "high" temperature (about 30K) supercon. The major problem with open MRI systems is the use of an iron framed magnet to capture the return field: the magnetic properties of iron are very temperature-sensitive so most of the engineering effort (once we had built a large enough shielded room and foundations to support 150 tons of machinery, and found 400 kW from the cables under the street) went into air conditioning. They say that the most reliable machine in your house is the refrigerator motor, which should run continuously for 20 years with no maintenance, but as soon as you scale it up to shift 200 kW of heat, you're lucky if it runs for a month!

My clients are currently installing conventional helium-cooled magnets in all sorts of trailers and temporary buildings. The newest cryostats don't use intermediate nitrogen, have a very small helium capacity (it used to be cheaper than beer but is extremely expensive nowadays)  and only need topping up every couple of years. But it would still be nice to get rid of the stuff, if only because it is a dwindling and irreplaceable resource.

Maintenance engineers nowadays spend most of their time fixing increasingly complicated and unreliable data networks. The last time I recorded a site safety "fail" was because the $2M mobile unit was connected to the main hospital by a single Ethernet cable (note to our readers - yes, there is an aether, and you can buy it by the meter, with plugs already attached) running across the car park.

[paul cotter]

There's a lot in that post that has aroused my interest. Me, personally, I would feel naked without at least a couple of mri machines in my possession, one in the kitchen, one in the bedroom and maybe one in a trailer that could accompany me in my travels. On a serious note I do have some questions. How the hell do you get helium down to 30k? What state is it in? ( I can't remember critical temps and pressure for helium -not sure if I ever knew ) You somewhat contradicted yourself when you said the relevant cryogenics were relatively trouble free yet the necessary compressor might only last a month, or did I misinterpret? I assume you are in the business of renting medical equipment-don't answer if this is considered too intrusive. Signed, your friendly pedanticist. PS I apologise for suggesting, without evidence, that you were retired. I had made the assumption since you always seem to have time to spar with BC, Hamdani and occasionally me, that you, like me, have too much time on your hands.