Types of NMR Magnets

Nuclear Magnetic Resonance Imaging, known as NMR in scientific circles and MRI in the medical field, is a way of imaging the body or a chemical compound. The main component of the MRI machine is the superconducting magnet that generates high electromagnetic fields. There are several types of magnets available for NMR use.

UHF

• When MRIs need to create a high power output, a superconducting ultra high frequency magnet is used. These magnets operate at frequencies of 300 megahertz and 3 gigahertz. UHF magnets need heavy shielding otherwise it can disrupt electrical equipment. UHF magnets create high level electromagnetic fields, which create the best quality images.

Resisitive

• Low-field NMR machines can use a resistive electromagnet to create the needed electromagnetic fields and are less expensive than their superconducting counterparts and are easier to maintain. The exchange is these are less powerful and do not create the same high quality images. They are often made of a common metal such as copper or aluminum.

Permanent

• While the UHF and resistive magnets have been electromagnetic in nature, meaning an electrical current must be passed through them to create an electromagnetic field, some machines use permanent magnets. These magnets are naturally attractive and create an electromagnetic field without the use of an electrical current. These are the least powerful NMR magnets and the largest and heaviest.