TOMOGRAPHIC INVESTIGATIONS OF WOOD FROM MACROSCOPIC TO MICROSCOPIC SCALE

摘要

Computed tomography based on transmission measurements of penetrating ionising radiation can be a powerful tool for the characterisation of wood and wood based materials. This includes not only structural appraisal but also dynamic processes and interaction with different substances (e.g. water, repellents, preservatives, adhesives, etc.). The different kinds of radiation on which these tomography methods are based show large variations concerning their respective sensitivity for the elements concerned and thus different fields of application: (1) X-ray tomography can be used on a macroscopic level, where wooden objects of several tens of centimetres can be examined, while (2) synchrotron radiation can be used for microscopic investigations down tothe cell wall level. (3) Imaging with thermal and cold neutrons with their high sensitivity towards light elements such as hydrogen on the other hand is thus particularly suitable for investigations on the interactions between wood and hydrogenous substances (water, adhesive, ...). In the presented work, tomographic methods based on the three named radiation types will be characterised with regards to their application area on practical examples ascertained at the facilities of the Paul Scherrer Institut Villigen (Switzerland).