Localization of vacuum breakdown locations in RF structures using S-parameter data

This project is an investigation to find the breakdown locations using a new method involving group delays of the Scattering parameters (or S-parameters). The RF signals of the T24PSI 1 from the Xbox-2 test stand at CERN have been used to parasitically estimate the S-parameters of the structure during high-power testing. The derivative of these parameters with respect to frequency are calculated to find the group delays, which lead to the breakdown locations. It is found that the method has worked perfectly well on normal pulses, and has reproduced the length of the test structure as the distance travelled. When the method is applied on breakdown pulses, the noise and the complex nature of breakdowns, with unknown reasons, have undermined the capability of the method in calculating the correct breakdown locations.