Patent ID: 8446150

Claim:
An apparatus for logging in a borehole comprising: longitudinal tool body having a first longitudinal axis therethrough; a longitudinal pad having a longitudinally extending shaft formed on an end thereof, a radioactive source disposed in the longitudinal pad to emit radiation into a formation surrounding the borehole; a sensor disposed in the longitudinal pad and longitudinally spaced apart from the radioactive source to detect scattered radiation from an interaction of the source radiation with the formation; a cap having a longitudinal cavity formed therein to receive the longitudinally extending shaft to allow relative rotation of the longitudinal pad relative to the cap about a second longitudinal axis extending through the cap cavity, the shaft, and the longitudinal pad by no greater than a predetermined angle to allow the longitudinal pad to align with a wall of the borehole when extended thereto; and a linkage coupled on a first end to the longitudinal body and on a second end to the cap, the linkage pivotable with respect to the tool body and the cap to allow the longitudinal pad to be radially extended from the tool body to contact a wall of the borehole such that the second longitudinal axis and the first longitudinal axis remain substantially parallel.