Re: How is nuclear spin measured?

Hi Terry,

Sorry for the late response. Nuclear spin is not exactly like our classical idea of a rotating sphere, but arises from the intrinsic spin of the nucleons (which in turn arises from the quarks within the nucleons, but let's keep things simple...) magnetic moment.

If you have an external magnetic field, there will be different energy levels for when the magnetic dipole of the nucleus is parallel or anti-parallel to that field. Electromagnetic radiation with an energy (frequency) equal to the difference between these two energy levels will cause the nucleus to resonate between them, and by measuring these resonances you can determine the magnetic moment. This is the principle behind Nuclear Magnetic Resonance which is how nuclear spin is usually measured. Another, similar measurement technique using nuclear spins is magnetic resonance imaging, or MRI.

I hope this is helpful.