Status and Experience with the Alignment of LINAC4

LINAC4 (L4) is an H-linear accelerator that will deliver, for the High Luminosity LHC (HL-LHC) project requirements, a beam of protons at 160 MeV energy to the PS complex and then to the LHC. Its connection to the PS booster will take place during the Long Shutdown 2 (LS2) in 2019-2020 or earlier if any major failure of the LINAC2. The Linac4 project requires the precise alignment with a tolerance of about +/-0.2 mm in both the horizontal and vertical planes, ofelements along approximately 150m beam line.This paper will give a status, an overview of the challenges of the alignment, the issues solved by the survey section, the techniques and methodology used to realise the survey activities over the last five years.