[time-nuts] Magnetic Resonance Spectrometer - redux

[Brian Lloyd]

On Sat, Jul 5, 2014 at 10:47 PM, Bob Stewart <bob at evoria.net> wrote:

> First, an apology.  When I changed the topic on my original post, I
> thought that would be OK.  Apparently that's still a thread-jacking.  Sorry.
>
> I'm still interested in this Magnetic Resonance Spectrometer thing,
> though.  On page 335 of the pdf linked below by Dave, there's an experiment
> with an MRS using water and the magnet from a magnetron available back
> then.  Apparently the resonant frequency of hydrogen nuclei in water is
> 6.131325 MHz in that magnetic field. Did anyone ever pursue this with the
> idea of creating a frequency standard, or was the technology just too
> primitive at the time?  Perhaps it's a repeatability problem from the
> magnetic flux standpoint?  I can guess that temperature changes would cause
> enough of a flux strength change to cause a problem, but that's just a
> guess.
>

The substance recommended was Ferric Chloride as I recall. The
characteristic was that the peak occurred quickly even with the rapid
change in the B-field. The B-field was modulated at a 60Hz rate, enough to
sweep the resonance across the oscillator's frequency. When the nuclei
precessed at the frequency of the oscillator, the nuclei would absorb power
from the oscillator, changing the plate-current of the oscillator. It was
really just a fast grid-dip oscillator. (Well, plate dip oscillator.)
Pretty simple.

I keep threatening to build a new one that works much better and has a
wider range, just to prove that I can. :-)

And I can't think of any way of tying this to time-nuttery. If there are
others still interested in this topic perhaps we can just communicate
off-channel.

-- 
Brian Lloyd
Lloyd Aviation
706 Flightline Drive
Spring Branch, TX 78070
brian at lloyd.com
+1.916.877.5067