Diagnostics and Measurement Strategy for the CERN Linac 4

Linac4 is a 160 MeV H linac which will become the new injector for CERN’s proton accelerator chain. The linac will consist of 4 different RF structures, namely RFQ, DTL, CCDTL and PIMS running at 352.2 MHz with 2 Hz repetition rate and 0.4 ms pulse length. A chopper line ensures clean injection into the PS Booster. The combination of high frequency and a high-current, low-emittance beam calls for a compact design where minimum space is left for diagnostics. On the other hand, diagnostics is needed for setting up and tuning of the machine during both commissioning and operation. A measurement strategy and the corresponding choice of the diagnostic devices and their specific use in Linac4 are discussed in this paper.