An Absolute Wireline Calibration to Support a Test of Newtons Inverse Square Law

Citation:
Ander, ME, Kerr W, Aiken CLV, Glover CC, Zumberge MA.  1990.  An Absolute Wireline Calibration to Support a Test of Newtons Inverse Square Law. Geophysics. 55:920-923.

Date Published:

Jul

Abstract:

As part of a Greenland ice cap experiment to measure possible scale length violations of Newton’s inverse square law over geophysical scales of 200 to 1500 m, it was necessary to locate the depth of a gravity meter attached to a wireline down a borehole to about 1 part in 10 000. In order to do this, the wireline and cable length measuring system had to be calibrated both before and after the Greenland expedition. The measuring system used a combination of a mechanical wheel measuring device and a magnetic mark counter. The calibration was conducted in a 1200 m vertical mine shaft at the Consolidated Silver Mine in Osborn, Idaho. Distances in the mine shaft were first calibrated to a precision of about 0.005 m using a geodetic laser system model 4L Geodimeter operating at 30 MHz. To calibrate the wireline, it was run up the mine shaft five times before and five times after the Greenland experiment. The calibration before the experiment was good to about 4 parts in 10 000 and the calibration after was accurate to about 1 part in 10 000. A total inelastic stretch of only 0.102 m occurred during the Greenland operation.

Notes:

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DOI:

10.1190/1.1442907