Nuclear Magnetic Resonance Spectroscopy in Superconducting Magnetic Fields

The first high-resolution nuclear magnetic resonance spectrometer operated at 30 Mcy/sec (7.05 kilogauss). The magnets constituted the only major obstacle to raising the frequency, but by continuous development over 10 years this frequency for proton resonance was increased to 100 Mcy/sec (23.4 kilogauss). Now, in one step, a system has been made to operate at twice this frequency and field intensity. It is not expected that superconducting magnets will generally replace iron magnets, but it is interesting to note that very few laboratories use the 30- and 40-Mcy/sec proton systems today. Notwithstanding the cost and operating problems of the superconducting magnet system for the nuclear magnetic resonance spectrometer, the fact that this is the only practical means of developing both a stable and a high-intensity field puts it in a class by itself. For this reason, even though the maintenance of spectrometers with superconducting magnets requires rather specialized skills, this type of instrumentation will clearly have an important role in advancing scientific knowledge, by making possible analyses which have not been possible with presently available instruments.