Model Test of Biperiodic L-support Disk-and-Washer Linac Structure.

A disk-and-washer (DAW) structure with biperiodic L-support was studied. Aluminum models were fabricated by calculation studies. Information for tuning the frequency was accumulated through cold model measurements. The material strength of oxygen free copper (OFC) was measured for the fabrication of the high-power model fabricated with OFC. A load test confirmed that OFC was enough sufficiently strong for this structure, although the DAW has structural complexity. On the basis of these results, eleven two-cell-units with a high-power model cavity made of OFC were fabricated. The accelerating mode and coupling mode frequencies of the entire structure were evaluated to be -1.1 MHz and -3.5 MHz, respectively, within the operating frequency of 2857 MHz, and ±2% electric field flatness was achieved. These values are sufficient for the requirements of a high-power model. A detailed design which aimed at electron acceleration was established for the DAW structure with biperiodic L-support.