Accession Number : AD0714569

Title :   Cryogenic Gravity Meter.

Descriptive Note : Combined scientific rept. nos. 1-2,

Corporate Author : STANISLAUS STATE COLL TURLOCK CALIF

Personal Author(s) : Tuman,Vladimir S.

Report Date : JUN 1970

Pagination or Media Count : 50

Abstract : The report describes the progress made towards the design and fabrication of a cryogenic gravity meter intended to have a sensitivity of about 25 millimicrogal. The cryogenic gravity meter consists of two parts--a suspension unit and a detection module. The suspension unit is a cylindrically symmetric superconducting magnet with a large magnetic field and a small magnetic field gradient at its geometrical center which supports a superconducting hollow niobium sphere. The detection module is a Josephson junction magnetometer which detects the magnetic flux change due to the motion of the hollow sphere. A feedback circuit is used to keep the magnetometer phase locked on the motion of the sphere; a portion of the feedback signal is recorded on an analog recorder. The signal on the recorder is directly proportional to the position of the sphere. The analog records obtained from a chart recorder are digitized, then a Fourier transform is performed on the data. The analyzed data indicates that spheroidal oscillations of the earth have been observed with this instrument. (Author)

Descriptors :   (*GRAVITY, *MEASURING INSTRUMENTS), CRYOGENICS, MAGNETIC DETECTORS, MAGNETOMETERS, SUPERCONDUCTORS, SUSPENSION DEVICES, CIRCUITS, MEASUREMENT

Subject Categories : Geodesy
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE