Introductory NMR & MRI: Video 04: Acquiring a Free Induction Decay (FID)

Paul Callaghan gives an introduction to NMR and MRI. This is the 4th video of the series in which the acquisition of an FID is explained. 10 episode series produced by Magritek Ltd.

[@neanderslob]

"I suppose I should convince you that this is actually water." LOL, dude you're going on about nuclear precession, spin molecular interactions and field inhomogeneity. I'll take it on faith that the clear stuff in the water bottle is ACTUALLY water. ;) Great video series, it really helped me out in my coursework.

[@WalkerDestroyer]

outstanding presentation skill, great job

[@uhaveit4real]

Thank You dude! you are awesome! helped me with my course

[@Ashlingaccount]

Great videos, thanks :)

[@ladybugcdl]

Thank you

[@ericnstewart]

I'm a little confused about the pre-polarizing pulse. It seems like the direction of that field would need to be the same as the static field (earth's), but the field produced by the outer coil of the Terranova looks like it would be oriented orthogonally. Where's the mistake in my thinking?

[@Observ45er]

Paul,
As an EE, I understand very well: resonance, presession, NMR in hydrogen and both the time and spectrum (fourier) domains as well as most of the other fundamentals, but have the same issue as Eric Stewart below: The difference between the pre-polarizing "pulse" and the earth's field illudes me. If Earth's field is producing the main precession causing field, what does the pre-polarizing field actually do? Does it shift the hydrogen moments away from the vertical to the horizontal so we can then watch the precession decay back to the Earth orentation? I thought that required an AC field that is resonant with the Hydrogen's precession freq. Is the pre-polarization field a DC field, or 2+ kHz field?
On to #5...
Regards, Steve N.