A digital approach for phase measurement applied to delta-t tuneup procedure

Beam energy and phase in a Linac are important parameters to be measured in order to tune the machine. They can be calculated by the time of flight of a beam bunch over a known distance between two locations, and by comparing the phase of a cavity to the beam phase. The phase difference between two signals must be measured in both cases, in order to get the information required. The electronics to be used for this measurement must meet stringent requirements: high bandwidth, good accuracy and resolution have always been a challenge for classical analog solutions. A digital approach has been investigated, which provides a good resolution, accuracy independent on the phase difference value, good repeatability and reliability. Numerical analysis have been performed, showing the system's optimal performance and limitations. A prototype has been tested in the laboratory, which confirm the predicted performance, and proves the system's feasibility.<>