ANALYSIS AND IMPROVED DESIGN OF GAMMA-RAY BACKSCATTERING DENSITY GAGES

THE NUCLEAR REACTIONS WHICH GAMMA RADIATION MAY UNDERGO IN A MATERIAL OF MEDIUM ATOMIC WEIGHT, SUCH AS SOIL, ARE DISCUSSED AND RELATED TO THE PROPERTIES OF BACKSCATTERING DENSITY GAGES. THEORETICAL REASONING AND EXPERIMENTAL EVIDENCE ARE PRESENTED TO SHOW THAT THE EFFECT OF THE CHEMICAL COMPOSITION OF THE MATERIAL MAY BE ELIMINATED WHEN' /A/ THE DETECTOR SEES MATERIAL NEAR THE SOURCE, AND /B/ PHOTONS OF ENERGY BELOW 0.1 MEV ARE NOT DETECTED. THE LATTER MAY BE ACHIEVED WITH A SCINTILLATION COUNTER AND PULSE SELECTOR OR BY PLACING IRON FILTERS IN FRONT OF A GEIGER-MULLER TUBE. THE GEOMETRY DEFINED BY /A/ CAUSES THE PEAK IN THE CALIBRATION CURVE TO MOVE TO A DENSITY SO HIGH THAT THE COUNT RATE BECOMES A UNIQUE MEASURE OF DENSITY, RISING OVER THE ENTIRE RANGE OF DENSITY FROM 0 TO 160 PCF. ERRORS IN THE DENSITY READING DUE TO THE STATISTICS OF NUCLEAR COUNTING AND SURFACE ROUGHNESS ARE DISCUSSED. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1966/107/107-001.pdf
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Preiss, K
• Publication Date: 1966

Media Info

• Media Type: Digital/other
• Features: Figures; References;
• Pagination: pp 1-12
• Monograph Title: Nuclear applications
• Serial:
  • Highway Research Record
  • Issue Number: 107
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Analysis; Backscattering; Chemical composition; Density; Errors; Filters; Gamma rays; Measurement; Measuring instruments; Nuclear reactions; Reading; Scintillation counters; Soils; Texture
• Old TRIS Terms: Density measurements; Filter protection; Geiger counter
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00215796
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Nov 18 1994 12:00AM