RF beam position monitors for the TESLA Test Facility

For the TESLA Test Facility beam position monitors with a precision of about 10 /spl mu/m are required. A circular cavity excited in the TM/sub 110/-mode by the off-axis beam provides a signal strong enough for various injectors. Expected signal to noise ratios and the theoretical resolution are estimated for a designed structure. A coaxial combiner was designed for common mode rejection. It is also foreseen to test different low-impedance monitors behind the injector. A structure using two coupled cavities is briefly described.<>