Ok well I should be to the lab tomorrow, I hope and will take a pic. of these magnets. Smart people here know about magnets! Very interesting these look the same as on the ribbon mikes. So this is going to be about it so far, my own experiments as well as AM radio move very slow. I don't want to take up a lot of space here since it is not AM, just want to ID the magnets & see if I want to try it again if they are better.
Magnetron is an interesting idea. I can't think of any off-hand tubes that would do for that kind of experiment.
Don't stick you finger in it.
How you get to absolute zero. -- Nuclear magnetic resonance of paramagnetic salts.
Ohio State University, 1964
That is way far beyond my pay grade.
Neat, what compounds are you analyzing? I used NMR in school studying chemistry but that been 25+ years now...
I'll use Hydrogen (water) to start for testing if it works and for calibration. It's all I could ever detect with the previous unit, had about 1200 Gauss and I dissolved a couple drops of ferric nitrate in the 0.5cc or so of water to make it more sensitive as advised in the "amateur scientist" book, I have to go back to the notes. I don't understand how this made H more detectable, maybe I missed something else.
I hope I can get 0.5 to 1 Tesla from these. What helps is a magnetic field measurement set from the military that I picked up. Its probe is about 3/4" wide. before I decide the gap to use, I have to consider the diameter of any test tubes for samples and of course the width of the field modulation coils. -it's easier to modulate the field a bit to find the element than modulate the frequency.
There's a chart with these materials and their relative sensitivities to the experiments. (didn't say dB or V)
Hydrogen 1H 1.0
Oxygen 17O 0.026
Fluorine 19F 0.83 (forget that!)
Aluminum 27Al 0.21
Copper 65Cu 0.1
and a bunch of others, isotopes, other stuff. For me it has to be only what's simple and safe.
A reason for measuring the field first is the Larmor frequency, as determined by the choice of nucleus and magnetic field. So my previous experiment with Hydrogen ran about 5MHz for the RF, but if I get for example 1.2T (12000G) from the new magnets then the frequency would be about 50Mhz. It's like tightening a piano string, the tighter it is, the higher the pitch. It's a linear thing, F(Lamor freq)=x(constant for given nucleus)*B(field strength) if that's right.
The way it works is you send a pulse of RF through the sample coil, then listen on the same frequency for the spin echo from the nuclei in the molecules of the sample -they vibrate, precess on their axis, if one can believe the drawings.
The RF power is small, was small, maybe 10W the last time. But you can see it would be a PITA to sweep the frequency while pulsing and trying to listen between pulses - much more complex issue. Easiest to try to figure out the general range of the magnetic field, then measure it with the appropriate instrument, and then think about assembling the experiment the right way the first time.
So, a couple ways to measure the magnet.. either sweep the RF frequency and listen, or use an instrument to measure the Gauss.
Realistically, it probably will be only a fraction of 1T, and because I want to have a tight gap to make the most uniform and strongest field. I am also considering using a pipette for samples which is about 1/4" diameter. A guy has a web page about his setup using what looks like a little pipette, very nice. More complex than I plan.
