Selective Suppression of TM_{020} Mode Leakage in Damped Cavities via Integrated Narrowband Filter

摘要: The TM020 mode damped cavity enables compact accelerators but suffers from severe electromagnetic field leak- age due to coupling-slot misalignment and structural asymmetry. We propose an integrated narrowband filter based on RLC circuit design to selectively suppress TM020 leakage while preserving higher-order modes damping. Crucially, the filter reduces electromagnetic field leakage to below 0.6%—over an order of magnitude lower than unfiltered cav- ities (>4%)—and enhances fourfold increase in positional tolerance (± 0.8 mm vs. ± 0.2 mm). Impedance spectra confirm minimal impact on higher-order modes damping. Under 20-kW power, thermo-mechanical analysis shows exceptional stability: peak temperature rise ≤21.3 K, frequency detuning ≤0.182 MHz, and leakage increase to only 0.65% (still 6 times lower than unfiltered baselines). This design resolves the critical leakage-robustness trade-off in next-generation synchrotrons.