Nuclear density gauge

A nuclear density gauge comprising

• a base having a surface adapted to be positioned on a surface of a material sample;
• first and second gamma radiation detectors carried by said base and mounted at a predetermined location relative to an axis extending longitudinally of the base;
• a gamma radiation source having a characteristic primary energy and a total activity of no more than 500 microcuries;
• a source mount carried by the base and mounting the gamma radiation source for longitudinal movement along said axis between an active first position located at a first longitudinal distance from said first and second detectors and an active second position located at a second longitudinal distance from said detectors;
• and
• means for calculating a value for the density of the material sample based upon the gamma radiation detected by said first and second detectors.

A nuclear density gauge comprising

• a base having a surface adapted to be positioned on a surface of a material sample;
• first and second gamma radiation scintillation detectors carried by said base and mounted in side-by-side relationship on opposite sides of an axis extending longitudinally of the base, detectors each including a photon-emitting crystal and a photomultiplier tube cooperating with the photon-emitting crystal for generating electrical signals proportional to the intensity of the photons, and wherein said crystals are of a square shape and are positioned next to one another on opposite sides of said longitudinal axis to form a rectangle with a longer dimension extending transverse to the longitudinal axis;
• a gamma radiation source having a characteristic primary energy and a total activity of no more than 500 microcuries;
• a source mount carried by the base and mounting the gamma radiation source at a location spaced along said longitudinal axis from said first and second detectors;
• and
• means for calculating a value for the density of the material sample based upon the gamma radiation detected by said first and second detectors.