EVALUATION OF SURFACE NUCLEAR MOISTURE-DENSITY GAUGES

Evaluatory findings (relative to gauge calibrations, composition effect, temperature effect, gauge operating characteristics and manufacturer's repair service) are presented for three different nuclear moisture-density gauges. The metallic and mineral standards used for the calibration are described. In the calibration procedure, metallic standards are used to establish the slope and shape of the calibration curve and the mineral standards serve to locate the curve. Graphs are presented which illustrate typical calibrations. In the NIC-5 gauge (in which the readout of moisture and density determinations is directly in pounds per cubic foot through a utilization of the dual-gauge principle), it was necessary for the gauge calibration adjustment to be set approximately 23 p.c.f. lower than specified by the factory. Resulting density readings are presented and discussed. The Seaman Model "75" (in which the count read-out is through three conventional decade-counter tubes and the density determination is intended to be conducted by the air gap method only) is rapidly and easily calibrated. With the Troxler gauge (the count read-out is by four Nixie tubes; is equipped with a built-in air-gap stand, and is designed for backscatter, air-gap and direct transmission test modes), composition error is considerably reduced. The procedure for determining the temperature effect is described and the results are presented and discussed. Details are given of such aspects as gamma radiation shielding and neutron shileding. An addendum gives details of the (one-piece unit) Portaprobe B (R) Mark II which is designed to measure density in direct transmission, back-scatter and air gap configuration.

  • Corporate Authors:

    South Dakota Department of Highways

    Physical Research Section
    Pierre, SD  United States  57501
  • Publication Date: 1972

Media Info

  • Features: Appendices; Figures; Tables;
  • Pagination: 22 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00262082
  • Record Type: Publication
  • Report/Paper Numbers: Progress Report II
  • Files: TRIS, STATEDOT
  • Created Date: Oct 22 1974 12:00AM