In order to examine the method we used the wide known MCNP computer simulation code and made the assumption that for gamma-densitometry the 241Am isotope was the proper source of gamma-rays.

Investigating the attenuation of gamma-rays by wood we tested the influence both of collimation systems and a type of standard sample material on the measured values. We found that due to the beam divergence all collimation systems introduce some deviations to the attenuation principle. From the practical point of view we recommend the necessity of the calibration standard sample of the same thickness as measured board independently on used collimation systems. The best material for the Standard sample is uniform plastic with the density lower than 1 g/cm³.
Additionally the empirical formula describing the intensity of gamma-rays back scattered from wood is proposed and discussed.