The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 28, 1986
Filed:
Sep. 23, 1983
Douglas D McGregor, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
An apparatus for measuring the magnitude of a magnetic field in one embodiment includes a .sup.3 He cell having an oscillator connected thereto for producing an electrical discharge for metastable .sup.3 He atoms, a .sup.4 He lamp having an oscillator connected thereto for producing .sup.4 He radiation and an optical path to the .sup.3 He cell including a lens for collimating the .sup.4 He radiation and a circular polarizer. The imaged .sup.3 He atoms and .sup.4 He radiation interact to magnetize a portion of the .sup.3 He atoms in a direction parallel to the direction of the ambient magnetic field. After the cell magnetization, an oscillatory magnetic field normal to the ambient field is established by coils connected to a frequency synthesizer which is scanned over a frequency interval including the free precession (Larmor) frequency. This action rotates the direction of magnetization of the .sup.3 He cell atoms from parallel to the ambient magnetic field to approximately perpendicular to the ambient magnetic field. The cell then is allowed to precess freely and an a.c. is induced in a coil during precession. The a.c. is connected to a frequency discriminator which may be a digital type to digitize the voltage representative of the frequency of the a.c. A very narrow band digital filter filters the digitized output of the discriminator and a digital to analog converter produces a voltage from the digital filter output for a charge recorder for charting.