Experimental and Calculated RF Properties of the Disk-and-Washer Structure

A detailed study of the disk-and-washer structure using SUPERFISH has shown that the physical geometry can be optimized to make the structure more efficient than previously reported. The calculated ZT2 is equal to that of an equivalent LAMPF cavity (neglecting any losses associated with the side-coupler slots) for ß = 0.6 and is 30% higher for ß = 1.0. Several techniques for supporting the washer were studied in addition to the conventional "L" supports. Two types of supports, the "TO" that supports two washers from every other disk with a T, and radial supports in the washer plane, improve left-right symmetry and reduce the tuning effort required to achieve a satisfactory field distribution. Effects of these supports on tuning procedures are discussed.