BEAM PHASE MEASUREMENT OF STORED BUNCH

We developed a system to measure synchronous phase angles for all bunches in the storage ring using an oscilloscope with high sampling rate. Precise phase measurement of specific bunch is required from the synchrotron radiation (SR) users, especially from the time resolved spectroscopy users. In a pump and probe experiment, the trigger timing for pumping laser should be precisely adjusted to the probe SR light. The timing of the SR light is affected by gap positions of insertion devices, filling pattern, bunch currents and so on. At the SPring-8, the bunch currents and the synchronous phase angles for all stored bunches are measured within 10seconds. The precision of the phase angle is about 5pico seconds. Combining this system with an averaged synchronous phase measurement system, we are now preparing to deliver the information of the synchronous phase angle to the SR users