[en] Excitation functions for the formation of tritium in nuclear reactions were determined for the target materials Al-27, V-51, Nb-93, and Au-197, the projectiles p, d, Me-3, a, and Li-6 for projectile energies up to 100 MeV (for protons only up to 45 MeV). The tritium formed in the irradiated thick targets was determined after hot extraction by activity measurement in a gas-filled counting tube. The measurement results obtained by this procedure are tritium depth distributions and thick target yields. From the thick target yields the slope of the cross section was derived as function of the projectile energy. The main properties of the excitation functions are surprisingly large cross section for (X,t...) - reactions of maximally 100 mb, which are extensively independent from the target material and show only a faint projectile dependence. Because of these properties it is relatively easily possible to estimate unknown excitation functions for (x,t...) -reactions accurately to a factor 2. The experimental data were compared with results of calculations according to the exciton model. Thereby the formulation of Machner yielded the best agreement. For the cluster formation probability of the triton in the excited compound nucleus values between 1% and 5% were found for the used projectiles. The energy spectra of the emitted tritons are only insufficiently reproduced by the exciton model. (HSI)