Developing Improved Nuclear Magnetic Resonance Marginal Oscillator Spectrometers for Advanced Teaching Laboratories

Abstract

Three marginal oscillator circuits are evaluated in their signal-to- noise performance in a complete nuclear magnetic resonance spectrometer. A circuit based on the hybrid Darlington source follower is superior to the other two, a modified Donnally oscillator and an FET cascade oscillator. Also the hybrid Darlington circuit has a voltage gain of 0.95 as compared, respectively, to 0.79 and 0.53 for the other two circuits. A sensitive but easy to understand phase sensitive detector of original design is presented as an integral part of the system, allowing simultaneous observation of the Lorentzian absorption signal and its derivative. Another new development is an external RF injection mode of operation of the marginal oscillators which permits observation of easily saturated NMR lines. Using this system, the variation of proton line widths in water as a function of the concentration of paramagnetic CuSO4 in the water is presented. Theses.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1988
Accession Number
ADA201129

Entities

People

  • Frank P. Willingham

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms

DTIC Thesaurus Topics

  • Amplifiers
  • Audio Amplifiers
  • Coordinate Systems
  • Detection
  • Detectors
  • Elements
  • Equations
  • Frequency
  • Magnetic Dipoles
  • Magnetic Fields
  • Magnetic Resonance
  • Monitoring
  • Nuclear Magnetic Resonance
  • Oscillators
  • Power Amplifiers
  • Radio Frequency
  • Radio Frequency Power

Fields of Study

  • Physics

Readers

  • Electronics Engineering
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.