RFQ-, chopping- and funneling-studies for the ESS-injector-linac

The front end of the ESS Linac has to provide a bunched high current H-beam with a special time structure for injection into the following DTL. This can be achieved by a system of two 175 MHz RFQ lines, each with a current of 54 mA, whose beams will be combined in a funnel section to a 107 mA beam with a bunch repetition rate of 350 MHz. For a proper operation of the compressor rings the linac beam must be chopped with a 60 % duty factor at the ring revolution frequency of 1.67 MHz which implies beam pulses of 360 ns and gaps of 240 ns during the macro pulse of 1.2 ms. A layout of the chopping line will be presented. A new concept for beam funneling using a two-beam RFQ and a multigap funneling deflector will be discussed. (author)