Patent ID: 6310936
Filing Date: 2001-10-30
Classification: G01B,G01N

Abstract:
A nuclear gauge suitable for measuring the density of a thin layer of material overlying a base material, comprising:a gauge housing having a vertical cavity therethrough and a base;a first radiation detector located at a first position within said housing and adjacent to said base of said housing;a second radiation detector located at a second position within said housing and adjacent to said base of said housing;a vertically moveable source rod extending into said cavity of said gauge housing;a radiation source operatively positioned within a distal end of said source rod;at least one bearing operatively positioned to guide said source rod within said cavity; andmeans for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors;wherein said source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.