UPGRADE OF BEAM PHASE MONITORS FOR THE ESRF INJECTOR AND STORAGE RING

The measurement of the phase relation between the stored beam in the Storage Ring and the beam circulating in the Booster Synchrotron is now done with high precision and at high speed using a single unit of commercial BPM electronics. The quadrature demodulation done in these digital electronics on each of its four RF input channels and the availability of the I/Q components at different output rates make the precise measurement of the relative phase relation, easy and strait forward. The RF signals of the relatively low current Booster come from two stripline outputs while that of the Storage Ring from two small BPM buttons. Treating simultaneously four signals, thus with a redundancy of two to measure the phase between two sources, allows to perform intrinsic shot-to-shot cross verifications on resolution and reproducibility. The long-term stability of this device has also been assessed by verifications against temperature drifts. An identical unit has now been added for phase measurements between the Storage Ring beam and the RF cavity signals.