Calibration Procedure For A Direct Scanning Densitometer Using Gamma Radiation


  • W. W. Moschler, Jr.
  • E. F. Dougal


Gamma radiation, attenuation coefficients, growth-ring characteristics, densitometer calibration


Direct scanning systems must be properly calibrated so that results may be repeated and verified. A calibration procedure was developed in which blocks of various wood species and densities were scanned with a direct-scanning wood densitomelcr using gamma radiation from a low (Fe55) and a high (Am241) energy source. Wood mass attenuation coefficients for Fe55 and Am241 were, respectively, 18.22 and 0.191 cm2/g at 8% equilibrium moisture content and 17.72 and 0.185 cm2/g under ovendry conditions. These results compare closely (<4%) with those reported in the literature: and as variations in wood characteristics are further quantified, the accuracy of this direct scanning system should improve.


Cown, D. J., and B. C. Clement. 1983. A wood densitometer using direct scanning with X-rays. Wood Sci. Technol. 17(2):91-99.nFerraz, E. S. de B. 1976. Wood density determination by attenuation of low-energy gamma radiation. IPEF, Piracicaba (12):61-68.nHandbook or Chemistry and Physics, 41st cd. 1960. C. D. Hodgman, ed. Chemical Rubber Publishing Co., Cleveland, OH.nKanowski, P. 1985. Densiliimetrie analysis of a large number of wood samples. J. Inst. Wood Sci. 10(4):145-151.nMay, H. A., H. P. Schatzler, and W. Kuehn. 1976. Measurement of the density profile of chipboard by means of gamma rays. Kerntechnik 18(11):491-494.nOlson, J. R., and D. G. Arganbright. 1981. Prediction of mass attenuation coefficients of wood. Wood. Sci. 14(2):86-90.nParker, M. L., R. D. Bruce, and L. A. Jozsa. 1980. X-ray densitometry of wood at the W.F.P.L. Forintek Canada Corp., B.C. Canada. W.F.P.L. Tech. Rep. No. 10. 18 pp.nRanta, L., and H. A. May. 1978. Measuring the density profile of particleboard by gamma radiation. Holz. Roh.-Werkst. 36(12):467-474.nWoods, F. W., and W. T. Lawhon. 1974. Gamma densitometry of increment cores. Forest Sci. 20(3):269-271.n






Research Contributions