Abstract: An apparatus for measuring externally of the human body magnetic susceptibility changes within the body particularly the human heart and interpreting these changes in order to quantify the flow of blood.

Abstract: A strip of material is reacted in situ with a chemical agent so as to create a chemical change affecting the magnetic properties of the material. From past history with the same kind of strip under identical conditions of reactions with the chemical agent, data such as time of exposure, temperature and partial pressure are recorded providing a calibration of any sensed magnetic property changes in such strip. An accurate direct measurement is thus made possible with an identical strip exposed to unknown temperature or partial pressure, by sensing of the degree of magnetization of the strip.

Abstract: An optical gaussmeter for determining the magnitude and homogeneity of the magnetic field in the core of a superconducting magnet includes a crystal of calcium fluoride doped with divalent thulium disposed in the core of the magnet. The crystal is exposed to RF radiation and to a narrow beam of light filtered to a wavelength corresponding to the absorption band of the divalent thulium in the crystal. The light beam signal as altered by the absorption characteristics of the crystal corresponds to the measured magnet current which manifests the field magnitude to be determined.