Measurement and alignment of the TIDVG5 SPS beam dump

During the Long Shutdown 2 (LS2 2018-2021) the CERN injector complex was upgraded to meet the future High Luminosity-Large Hadron Collider (HL-LHC) re- quirements. One major activity was the construction and installation of a new beam dump, in the Super Proton Synchrotron (SPS), able to cope with the increasing brightness of the high luminosity beams. The challenge for survey engineers was to align the beam dump and especially the core of the component within the tolerance required by the physicists. The measuring system had to ensure a transverse align- ment tolerance of ±0.7 mm (3σ) with respect to the beam axis defined by the surrounding quadrupoles, while facing many external constraints. A 2 m thick wall, composed of steel, concrete and marble, shields the new beam dump. The estimated dose for a year of operation is 1 MGy at 35 cm from the core. In addition, a bakeout of the dump up to 150°C is required to ensure the needed vacuum quality. The system had to be reliable and failsafe as there is no manual access possible during the 20 years of service. These heavy constraints led to a complete study of the spatial measure- ment system for the equipment. The paper describes in detail the design of the measure- ment and alignment system from the initial idea to the pro- totypes and the production. It also provides an overview of the tests and the first measurement results achieved.