Paper | Title | Page |
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WEP178 | Electromagnetic Field Measurement of Fundamental and Higher-order Modes for 7-cell Cavity of PETRA-II | 1822 |
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The booster synchrotron for NSLS-II will include a 7-cell PETRA cavity, which was manufactured for the PETRA-II project at DESY. The cavity fundamental frequency operates at 500 MHz. In order to verify the impedances of the fundamental and higher-order modes (HOM) which were calculated by computer code, we measured the magnitude of the electromagnetic field of the fundamental acceleration mode and HOM’s, using the bead-pull method. To keep the cavity body temperature constant, we used a chiller system to supply cooling water at 20 degrees C. The bead-pull measurement was automated with a computer. We encountered some issues during the measurement process due to the difficulty in measuring the electromagnetic field magnitude in a multi-cell cavity as compared to a single-cell cavity. We describe the apparatus for the field measurement and the obtained results. | ||