Theoretical Wood Densitometry: II. Optimal X-ray Energy For Wood Density Measurement


  • James R. Olson
  • C. J. Liu
  • Ye Tian
  • Qingbiao Shen


Optimal X-ray energy, wood densitometry, differential transmission probability, maximum radiation resolution, wood density


Using a comparable approach, we extended the theoretical X-ray wood densitometric models to a case encountered in practice. Optimal X-ray energy was treated as the photon energy of the X-radiation which produced the maximum radiation resolution, as measured by differential transmission probabilities detected in a densitometric experiment. Parametric representation of radiation resolutions revealed that the maximum resolution of a specific densitometric procedure is governed by the range of densities in a given wood. The maximum radiation resolution obtainable in a particular wood densitometric experiment can be calculated readily from two equations derived in this study. Examples show that under "good architecture" conditions (1) transmission probabilities for a given wood densitometric experiment increase their magnitudes as the X-ray becomes more energetic, yet the maximum radiation resolution remains constant for a given set of parametric values; (2) optimal X-ray energies, for nine types of coniferous wood, are in the range of 5.13-5.69 keV for 1.0-mm-thick samples; (3) wood with a broader density range results in higher maximum resolution when irradiated by the theoretically optimal X-ray energy; and (4) accurate wood density measurements could be achieved only if the radiation energy used was near the optimal level. Regarding the architecture of a radiation detection system, the advantage of using a monochromator to reduce the X-ray energy continuum so as to increase the accuracy of wood density measurements was examined.


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