Development of seven-gap resonators for the Heidelberg high current injector

Abstract A high current injector for the heavy ion storage ring TSR in Heidelberg is under construction. As a part of the injector eight seven-gap resonators with high shunt impedance are being developed. These resonators ( ƒ 0 = 108.48 MHz ) are designed for the synchronous velocities of β s = 3.7, 4.5, 5.1 and 5.7%. Low power models with scaling factors of 1:2.5 were built in order to study the characteristics of these new resonators. Following low level measurements to optimize the voltage distribution and eigenfrequency, a first power resonator was built and successfully tested at 80 kW (duty cycle of 25%). At this power, the resonator generated a maximum voltage (summation of all gap amplitude voltages) of 1.75 MV. This paper describes the design of the resonators and gives some details of the measurements.