RF characteristics of the APS storage ring isolation valve

The RF impedance of the isolation valve of the APS storage ring system was measured by the wire method with a synthetic pulse technique. The coupling impedance as well as the energy loss of the sector valve with and without an RF liner or screen, and the flange gap of the various sizes was measured. There appear to be resonances at certain frequencies without an RF liner that might cause an unacceptably large coupling impedance. Data with various sizes of the flange gap show that good RF contact around any flange is necessary. The impedance due to intrusions into the beam chamber was also measured. The results are compared with the computer simulation from MAFIA