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Cryogenic Gravity Meter.
Final rept. Aug 71-Sep 72,
STANISLAUS STATE COLL TURLOCK CALIF
Pagination or Media Count:
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 periods between 0.5 seconds to 3 seconds and Q from 2.3 to 20 have been studied in this report. Trapping of flux in the ball seems to be one of the major difficulties encountered. Author
APPROVED FOR PUBLIC RELEASE