A non-perturbing technique to characterize the indigenously developed spiral buncher cavity at high-power level

摘要

The High Current Injector (HCI) at Inter-University Accelerator Centre (IUAC) incorporates a spiral buncher cavity to provide the time bunching of charged particles at the entrance of Drift Tube Linac (DTL). The spiral buncher cavity is a two-gap RF structure with its remarkable properties such as high shunt impedance, compactness, and high-frequency stability. The cavity was designed, developed, assembled, and successfully tested at IUAC. The cavity has been designed for similar to 27 kV/gap at similar to 1 kW of input power. At the low power level, the bead-pull technique was used to characterize the cavity, and the X-ray energy spectroscopy method was used to characterize the cavity at a high-power level. The X-ray measurement technique was used to determine the gap voltage across the drift tubes without perturbing the field. A thallium doped sodium iodide-based scintillator detector was used to measure the emitted X-ray from a cavity. The cavity was powered at a variable power level, and the X-ray energy spectrum was recorded. The measured and simulated results match closely within the error of similar to 5%. The details of cavity characterization, high-power testing, and X-ray energy measurement method will be discussed in the article.