A waveguide High Order Mode Reflectometer for the Large Hadron Collider Beam-pipe

The feasibility of a waveguide mode reflectometer for the LHC beam-pipe has been studied. After a start-up phase devoted to getting some experience with network analysers and waveguide calibration, the most important electrical characteristics of the beam-pipe between 4 and 8 GHz have been determined in a resonator measurement. The interconnects were also examined thoroughly, for they may pose a significant problem for the reflectometer's operation. In the next step digital signal processing was applied to process the measurement data that is affected by various effects, especially dispersion. Some effects were closely examined in measurement and simulation. Finally the performance of the method was tested on the 50 m test track.