P. 0. Box 9665, New Haven, CT 06536 (203)624-8113
Mr. Murray Barlowe,
SCIENCE WORKSHOP BOX 310 BETHPAGE NY 11714
Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI)
employs high frequency radio transmitters, receivers, and computer science techniques to generate images or chemical spectra of organic materials. NMRIMRI techniques use methods developed between 1930 and 1945 for military RADAR. RADAR and
NMR/MRI both use Transmit/Receive circuits, state of the art receiver sensitivity, and good antenna (probe) design.
using radio frequency methods have not received much
attention in the amateur radio publications (Ham Radio, QST, CQ , and 73) since these publications are concerned with radio communications as an end use of RF techniques. There are a whole score of "non-communications" usage of RF techniques and
NMR/MRI would be one such use. You can "listen" to the radio signals produced by the nucleus of the hydrogen atom by exciting these photons to transmit, and make an image by reconstructing the matrix of protons. The technical challenge of building a system to do this might seem worth while to experienced amateurs.
modulation required for selective excitation of a group of protons
can be accomplished by using techniques similar to the early days of single sideband
modulation, using phasing (audio multiplication by RF) techniques. The Science Workshop "Poor Man's Spectrum Analyzer" provides a useful instrument to adjust the required circuits to assure a correctly aligned phasing-type SSB transmitter. No, the protons do not mail QSL cards, but the thrill of capturing a Free Induction Decay might serve as a substitute. All that is required is lots of patience and visits to flea markets, a few books on the subject, a large magnet, and determination.
I have been building
simple NMR systems since 1957, first using the earth's
magnetic field as a free proton magnet source. Since 1982 I have been a part of the technical support team at Yale's NMWMRI instrument group, certainly the most enjoyable time I have had using short wave techniques since getting my original ticket in 1938 (WSIMB).
I am unaware
of any amateur magnetic resonance interest or support group at
this time, but this would be a way of developing and sharing techniques and problems.
Wade G. Holcomb, WIGHU