Lifetime and operational criteria of proton beam instrumentation in the ESS target station

At European Spallation Source, a 2 GeV, 5 MW proton beam will be delivered from a superconducting linear accelerator to the target at 4% duty factor, which poses demanding requirements on the target station design. To avoid a failure of the target station components due to an accidentally anomalous behavior of beam optics, the current density, the halo distribution, and the position of the proton beam shall be measured. The proton beam instrumentation plug (PBIP) provides a suite for the beam monitoring devices that are important for the machine protection, which include the multi-wired grids for the beam profile monitoring, the thermocouple assemblies and the secondary emission blades for the aperture monitoring, and a beam footprint imaging system consisting of the optical components and a luminescent coating. Since these devices are exposed to a high dose of radiation damage and particle energy deposition, it is a significant challenge to ensure its full functionality. In this paper, the material selection, the lifetime and operational criteria of the beam monitoring devices in the PBIP are presented.