High-gradient near-quench-limit operation of superconducting Tesla-type cavities in scope of the International Linear Collider

We report the successful demonstration of an ILC-like high-gradient near-quench-limit operation at the Superconducting RF Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. Preparation procedures necessary for the accelerator operation were conducted, such as rf phase calibration, beam-based gradient calibration, and automated beam compensation. Test runs were performed successfully for nominal operation, high-loaded Q (QL) operation, and automated P(k)Q(L) operation. The results are described in terms of the achieved precision and stabilities of gradients and phases.