The Karlsruhe Tritium Neutrino experiment (KATRIN) is designed to measure the neutrino mass with a sensitivity of 0.2 eV (90% C.L.) by investigating the beta spectrum of tritium. This requires continuous monitoring of the tritium gas composition. The aim of this work was to develop a tritium-compatible Raman system suitable for in situ gas analysis at low pressures. Based on a hollow waveguide approach, a detection limit of 10^(-3) mbar was achieved in less than 60 s acquisition time.