Development of a Traveling Wave Accelerating Structure for a Superconducting Accelerator

The present state of the art for superconducting accelerating structures, needed for the International Linear Collider (ILC), has achieved a gradient of 35 MV/m. This project will design, develop, and demonstrate the Superconducting Traveling Wave Accelerating (STWA) Structure to further increase the gradient by a factor of 1.20-1.40. The STWA structure will operate at the same surface magnetic and electrical field magnitudes as the TESLA cavity surface, in order to avoid undesirable superconductivity break down. In Phase I, an L-band superconducting-structure copper prototype will be designed and manufactured. The L-band STWA cavity will be simulated and optimized with respect to magnetic and electrical surface field ratios, inter-cell coupling coefficients, and accelerating field flatness. The input-output high power couplers for the STWA structure will be designed and numerically simulated. A STWA prototype structure will be bench-tested to compare its electrical properties with design calculations. Commercial Applications And Other Benefits as described by the Applicant: A superconducting accelerating structure with the increased gradient should allow the total length of the ILC to be reduced by 20-40% with a corresponding reduction in construction costs.