Superconducting MR Spectrometer

Weighing about seven and a half tons, the magnetic resonance (MR) spectrometer was funded by a U.S.$2 million grant from the U.S. National Institutes of Health (NIH) in a strong competition among research universities. Since 2001, the NIH has funded only three such magnets nationwide, according to Brandeis professor of chemistry Dr. Tom Pochapsky.

Brought in by crane and located at a site protected from large metal objects and radiofrequency interference, the superconducting magnet was actually energized with about the same amount of power consumed by a big stereo, Dr. Pochapsky explained. First, the superconducting electric coils that create the magnetic field were bathed in liquid helium to drop the temperature to 2oKelvin or minus 456o F. Once the coils were super-cooled, electric current was able to pass through them without resistance, creating the magnetic field. Once at field, the magnet uses no power at all, although the large liquid helium tank surrounding the coil needs to be refilled about every six weeks.

Once the magnet has been fully tested, the Brandeis researchers, as well as other Boston-area universities occupied in NIH-funded biomedical research, will use it 24 hours per day. Experiments typically run in weeklong blocks, although some may run for several weeks at a time, according to Dr. Pochapsky.

Magnetic resonance is a physical phenomenon based on the magnetic property of an atom's nucleus. It occurs when the nuclei of certain atoms are immersed in a static magnetic field and then exposed to a second oscillating field, causing them to essentially line up and act in unison, similar to a brigade of marching soldiers, according to Dr. Pochapsky. The electrons, neutrons, and protons within the atom have an inherent characteristic known as "spin” and within the electromagnetic field created by the magnet, the frequency of the spinning motion of the atoms reveals information about the physical, chemical, structural, and electronic properties of the molecule in solution.

MR spectroscopy was first described more than 50 years ago, and is related to MRI imaging used in hospitals as a soft-tissue diagnostic tool. It is also utilized in chemical and biochemical research because it is the most advanced analytic tool available for determining the three-dimensional (3D) structure and motion of biologic molecules in solution. The average hospital-based MRI has an electromagnetic field of approximately 7 Tesla, whereas this superconducting magnet is more than twice as powerful, measuring a magnetic field of 18.8 Tesla, according to Dr. Pochapsky.




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