DISCUSSION OF CALIBRATION ON NUCLEAR METERS FOR MEASURING MOISTURE AND DENSITY

The calibration is outlined, of a scintillation-type neutron-moisture meter designed to avoid materials containing neutron absorbers. Artificial materials such as bentonite, silica sand, and sodium metaphosphate were used to adjust densities; water and sugar were added to provide the moderation component. When the calibration curve was used to predict the water content in a marine clay, a serious discrepancy was found amounting to 6 lb of water per cu ft. A new calibration curve was then determined for the marine clay (illustrated). Subsequent chemical analysis showed that this particular soil contained about 1 percent potassium and 7 percent iron (by weight) which accounted for an 11 percent reduction in thermal neutron activity by absorption. One must, therefore, understand the factors that affect calibration, and the feasibility is questioned of using one calibration for all soils.

Media Info

  • Features: Figures;
  • Pagination: p. 42-43

Subject/Index Terms

Filing Info

  • Accession Number: 00081225
  • Record Type: Publication
  • Report/Paper Numbers: STP 35 Conf Paper
  • Files: TRIS
  • Created Date: Mar 26 1975 12:00AM