THE LLRF MEASUREMENT AND ANALYSIS OF THE SSC-LINAC RFQ

The manufacturing process of the SSC-LINAC RFQ went to end and the LLRF measurement has been done. To reduce the disturbance from the test environment, a dielectric block has been used as the perturbation body instead of the beads. The error induced by the block and the sampling approach have been investigated. As the results, the frequency of the RFQ is 53.557 MHz without tuning, which is not far from the design value 53.667 MHz. The Q0 value is 4925.8. The unflatness of the field along the beam axis is less than ±4%, which meets the simulation results. The frequency will be adjusted by tuning plungers in operation. In this paper, the measured results of the field distribution along the cavity will be compared with the modulated electrodes simulation.(5 refs)