Mechanical design of the gamma blockers for the high-energy beam transport region of the European Spallation Source

The European Spallation Source (ESS) is a collaboration of 13 European countries to build the world’s most powerful neutron source for research. The project, situated in the south of Sweden, is approaching the end of the construction phase, and the first scientific results are planned for 2023. This paper gives an overview of mechanical design of the gamma blockers (GBs) in the accelerator to target (A2T) and dump line (DmpL) sections. The presence of GBs in the beam line should limit the gamma radiation emitted from the activated tungsten target and beam dump to allow the safe access of the staff to the machine. The presented design allows for efficient operation and the same shutting time independently of the vacuum status.