The coupled cell structures parameters for the large bore hole diameter

The enlarged beam bore hole is required, in the special RF cavity, for the purpose of the beam handling, to provide higher quality beams by using the KEK/JAERI joint project linac. To understand practical limits and cost on solution, at least consideration and comparison on structural parameters are necessary to be investigated. Therefore, parameters of coupled cell structures with enlarged bore hole radii were considered. They were not candidates with evident performance in RF parameters. All structures were close by RF effects, and possible difference of order in 10% looked like no reason for special development, especially taking into account that cavity was single on a case of linac. All of narrow band structures were based on deterioration of operating dispersion curve with increasing bore holes. This deterioration could be reduced by structures coupled with slots based on reasonable decreasing of the cavity efficiency. (G.K.)