Trapped modes analysis for the elettra booster DCCT installation

In the new Elettra full energy injector, bunch charge measurements will be performed by different types of current transformers (CT), depending on their position (single pass or multi pass sections). In the single pass sections (Linac and Transfer lines) a new type of current transformer (in-flange CT by Bergoz) will be used. Main advantage of this device is a compact and reliable design; they are also specially suited in space critical application. For the booster ring a standard DC current transformer will be used to measure the DC component of the circulating beam current. The housing has been developed in house, including the magnetic shield and the ceramic gap in the vacuum chamber. Furthermore, calculations of the trapped modes in the current monitor housing are described. Longitudinal coupling impedance and loss factors for these resonant modes are estimated and we showed that dissipated power is not critical with ELETTRA booster parameters.