Choice of materials for the construction of the TRT

This paper is mainly based on a compilation of existing experimental data and on the experience gained by the TRT collaboration over more than 8 years, concerning ageing phenomena in proportional gas chambers and radiation hardness of materials commonly used for the construction of gaseous detectors. Aspects of the impact of the choice of construction materials on the TRT straw behaviour in an environment with high radiation levels are discussed. Explicit recommendations concerning the design of the detector mechanics and of the active gas system are given wherever possible at the end of each Section.