Measurements on the frequency effects and coupling of slots and irises for the APT CCDTL

In preparation for the fabrication of the coupled-cavity drift tube linac portion of the Low-Energy Demonstration Accelerator for the Accelerator Production of Tritium project, the effects of coupling slots/irises have been measured and compared to theoretical calculations. A number of multi-cavity cold models have been constructed corresponding to various sections of the coupled-cavity drift tube linac. These models have been used to measure the average cavity to cavity coupling, the frequency effects of the cavity to cavity coupling slots, the coupling into the cavity structures from a waveguide through an iris, and the effect of the iris on the frequency of the cavity being driven. The results of these measurements have been compared to the theoretical values. The effect of a shorting plate placed in one of the feed waveguides was also investigated. This was used to approximate the position of a closed vacuum valve which would be used in the event of a vacuum window failure.