Nuclear magnetic resonance is one of the most powerful techniques used not only in the different fields of chemistry and physics but also in the field of medicine in which the magnetic resonance imaging (MRI) has become an important diagnostic tool rapidly replacing the conventional X-ray technology.
The physical foundation of the magnetic resonance lies in the magnetic properties of an atomic nuclei. Most nuclei including the proton and the electron possess inherent magnetic fields. A magnetic field is associated with any moving electric charge and because a proton has charge as well as spin , it will behave as it were a tiny magnet. Effects of the nuclear magnetic fields are too small to be observed in the ambient magnetic field of earth. However, in an intense magnetic field, the nuclei can assume specific orientation ( Interaction of the nuclear magnetic moment with an external magnetic field).Some of them align with the applied magnetic field ( lower energy state) and some of them align against the applied magnetic field ( high energy state). With the aid of high frequency transmitter transitions between the two state can be stimulated. Absorption of energy can be detected, amplified and recorded as a spectral line called resonance signal.
0 comments:
Post a Comment