Technical aspects of applying high frequency densitometry: Probe-sample contact, sample surface preparation and integration width of different dielectric probes

High frequency (HF) densitometry has been suggested as an alternative to X-ray densitometry for high resolution measurements of wood density. The propagation of this innovative technology so far has been limited somehow due to several unanswered questions, e.g. concerning requirements of sample preparation or integration widths of differently sized dielectric probes used. This study shows that the measurement precision of HF densitometry is high, its accuracy, however, is dependent on perfect probe-sample contact and thus requires high quality sample surface preparation as well as stable mechanics of the densitometer mounting. Preparation with an ultra-precise diamond flycutter is a reliable standard technique with precisely done sanding of samples being a possible alternative. Different geometrical setup and dimensions of individual probes’ electrodes result in different integration widths. The integration width is determined by the distance between electrodes and the thickness of the electrodes in the probe tip.