Tuesday, June 9, 2009

Measuring the strong force with MRI

MRI works because a proton that's in a strong magnetic field will polarize/align with the field and then behaves like a bell when it's hit with a radio wave (it rings back with another radio wave that we listen to in order to make an image).

Now typically in MRI we image hydrogen's proton in water (where it is bonded to oxygen). If we image hydrogen's proton in fat (where it is bonded to carbon) then the tone at which it rings changes slightly. If we image a sub-atomic particle with another proton/neutron right nearby in the nucleus (deuterium, helium 3, …) then the tone of ringing shifts much more. Potentially, these ring tone shifts could be an excellent way to further investigate the strong nuclear force (at present there is no mathematical equation defining the force which seems unsatisfactory). Ideally we could build an apparatus whereby we could control the distance (down to ridiculously small values) between two groups of protons. It would simplify our calculations if we could adjust the main magnetic field such that the ring tone (frequency) remained stable and we looked at the change in the main magnetic field (that keeps the ringing frequency stable) as a function of distance. From this change in magnetic field strength we might be able to calculate the strong force (when we factor in the known electromagnetic force) as a function of distance.

A ridiculously challenging experiment but whose results could be very interesting!