Half-power test of a CW proton injector with a 1.25-MeV RFQ

A 75-keV, 110-mA CW proton injector capable of pulsed operation has been developed for testing the LEDA 6.7-MeV CW radio frequency quadrupole (RFQ). Part of the preliminary development of this injector included operation of a 1.25-MeV CW RFQ at beam currents up to 100 mA. The 75-keV LEDA injector was modified to operate at 50 keV for these tests. We report here on the operational experience of the 1.25-MeV RFQ where 50-mA beam current was accelerated through the RFQ with 90% transmission. This half-power operation is of interest because (1) the injector beam current monitoring was more reliable, and (2) sufficient RF power was available to ensure the design cavity fields. These two features simplify the comparison of injector-RFQ performance with design codes. The information obtained from these studies will be applied to the 75-keV injector during the LEDA 6.7-MeV RFQ commissioning.