A Multi-Input Phase Measuring System

A multi-input phase measuring system is described which has been designed for the cyclotrons of HMI (Berlin) and EUT (Eindhoven). The phase probe signals are multiplexed to avoid phase differences between the various input channels. After the input multiplexer the signals are transformed to a fixed frequency. Therefore the system needs no adjustment for different acceleration frequencies (i.e. particle energies). Test signals well below 1 ?V can be measured with an accuracy of 0,1o, which is a characteristic of the phase measuring system. In the Eindhoven AVF cyclotron practical values for the lowest beam currents are about 15 nA for 3 MeV protons, due to signal disturbances of the cyclotron itself.