Progress in the Construction of Linac4 at CERN

As first step of the LHC luminosity upgrade program CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normalconducting linac made of a 3 MeV injector followed by 22 accelerating cavities of three different types. The general service infrastructure has been installed in the new tunnel and surface building and its commissioning is progressing; high power RF equipment is being installed in the hall and installations in the tunnel will start soon. Construction of the accelerator parts is in full swing involving industry, the CERN workshops and a network of international collaborations. The injector section including a newly designed and built H¯ source, a 3-m long RFQ and a chopping line is being commissioned in a dedicated test stand. Beam commissioning of the linac will take place in steps of increasing energy between 2013 and 2015. From end of 2014 Linac4 could deliver 50 MeV protons in case of Linac2 failure, while 160 MeV H¯ could be injected into the PSB from 2016; connection to the PSB will take place during a long LHC shut-down foreseen to begin end of 2017.