HIGH-SENSITIVITY NUCLEAR MAGNETIC RESONANCE FOR THE QUANTITATIVE ANALYSIS OF BODY FLUIDS.
Abstract
Magnetic resonance measurements on the electronic (free radicals) and nuclear (protons) moments in diphenylpicrylhydrazil were made using a superconducting tuned circuit as the sensing element. Two operating frequencies, 30 MHz and 0.95 MHz, were used in these experiments. Signal-to-noise improvements between 5,000 and 16,000 were obtained over the non-superconducting mode. The quality factor of the superconducting resonant circuits ranged from a low of 10,000 to a high of 2,800,000. A major limitation to high quality factor was the low temperature loss properties of the dielectrics used in the construction of the tuned circuit. Three types of detection schemes were used: (1) Rollins type, (2) Rollins type with MOS Fet amplifier held at 4.2K., and (3) Robinson-type marginal oscillator. Design criteria are presented to circumvent line broadening due to magnetic flux expulsion of the Meissner effect from the superconducting radiofrequency coil. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1967
- Accession Number
- AD0662323
Entities
People
- G. A. Persyn
- J. M. Victor
- W. L. Rollwitz
Organizations
- Southwest Research Institute