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From a quick survey of the article, it sounds like this instrument is likely to be using conventional electromagnets. Is that correct?
by ISL 7y ago
From a quick survey of the article, it sounds like this instrument is likely to be using conventional electromagnets. Is that correct?
- philipkglass 7y agoPermanent magnets, according to this article: https://www.fiercebiotech.com/medtech/fda-clears-world-s-first-portable-bedside-mri https://www.fiercebiotech.com/medtech/fda-clears-world-s-fir... Small permanent magnet NMR spectroscopy units first showed up in chemistry about 10 years ago: https://www.prweb.com/releases/2010/11/prweb4732684.htm https://www.prweb.com/releases/2010/11/prweb4732684.htm
- ISL 7y agoAh. Cool. Makes sense, as the field is clean and stable. NIST's Kibble balance does the same. Thanks!
- hinkley 7y agoMy understanding is that MRI’s use two magnetic fields in opposition. A strong field that is a superconducting magnet of fixed number of Teslas, and an electromagnet that is pulsed to cancel out part of the field. The pulsing creates an echo in the water molecules in the body which is then painstakingly processed into an image. That thunking noise has to do with the pulsing. I forget what it’s called now but you can build a permanent magnet of upward if .5 or 1T by packing a bunch of keystone-shaped rare earth magnets with differing field alignments into a high tensile strength retaining ring. This causes the fields to be additive, but God help you if you manage to break the damn thing. I watched a video on how to safely put two large rare earth magnets together without shattering them, and YouTube recommended an infomercial by some company at the high end of Tesla ratings for permanent magnets. It was kinda nuts.