XPost: sci.electronics.design   
   From: jl@glen--canyon.com   
      
   On Thu, 19 Feb 2026 14:13:06 +0100, nospam@de-ster.demon.nl (J. J.   
   Lodder) wrote:   
      
   >Bill Sloman  wrote:   
   >   
   >> On 19/02/2026 9:56 pm, J. J. Lodder wrote:   
   >> > Bill Sloman  wrote:   
   >> >   
   >> >> On 19/02/2026 7:49 am, Ross Finlayson wrote:   
   >> >>> On 02/18/2026 12:43 PM, Python wrote:   
   >> >>>> Le 18/02/2026 à 20:13, Ross Finlayson a écrit :   
   >> >>>> ..   
   >> >>>>> and, you know, magnetic monopoles, is widely employed   
   >> >>>>> in medical imaging and the like.   
   >> >>>>   
   >> >>>> No.   
   >> >>>   
   >> >>> Resonance imaging (NMR) is a thoroughly different mechanism   
   >> >>> than Roentgen rays.   
   >> >>   
   >> >> But as the name implies, it's nuclei of the atoms involved that exhibit   
   >> >> the resonance. It's a remarkably low energy effect, and you need   
   >> >> remarkably high magnetic fields to get it to give you a detectable   
   signal.   
   >> >   
   >> > Nevertheless, it is easily demonstrated in the kitchen   
   >> > with some simple electronics.   
   >>   
   >> Sort of.   
   >>   
   >> https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance   
   >>   
   >> There are lots of different ways to exploit nuclear magnetic resonance.   
   >> The earth's magnetic field is high enough to let you devise experiments   
   >> that can demonstrate the effect on a kitchen table.   
   >   
   >Nothing 'sort of'.   
   >You -can- easily demonstrate the effect on the kitchen table.   
   >(at audio frequencies)  Wikipedia is right here.   
   >   
   >Jan   
      
   NMR was a fairly popular analytical chemistry business for a while. We   
   made pulsed-field gradient coil drivers and temperature controllers   
   for Varian.   
      
   But superconductive magnets and liquid helium are expensive, and other   
   techniques took over. It was common to visit a lab that had a giant   
   magnet in the corner, warm and collecting dust. A similar mass spec   
   technique, FTMS,  died for the same reason... too expensive.   
      
   Agilent bought Varian to get their medical stuff but immediately   
   killed the NMR operation. I think Bruker still does NMR.   
      
   Hospitals prefer cat scans to MRIs these days. Cat scans are much   
   cheaper.   
      
      
      
      
   John Larkin   
   Highland Tech Glen Canyon Design Center   
   Lunatic Fringe Electronics   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)