The CERN SPL Chopper Structure. A Status Report

In the framework of HIPPI, a study for a Superconducting Proton Linac is being carried out at CERN. An integral part of the medium energy line is the chopper, which has to establish the required time structure of the beam by cutting out selected bunches from the continuous bunch train coming out of the RFQ. Due to the bunch spacing of 2.84 ns a system rise and fall time of 2 ns is required. A slow wave structure matched to the beam speed of 0.08c was chosen as the most promising candidate. This structure was implemented as a meander line printed on a ceramic substrate. The mechanical design as well as technological issues are discussed. Furthermore, the results of comprehensive tests on the prototype are reported.