Energy Deposition Studies for the Experimental Insertions of FCC-hh

Abstract

In order to explore new possibilities for particle physics for the post-LHC era, the Future Circular Collider (FCC) study was launched in 2014 to assess its feasibility. Different machines are considered, including a hadron collider machine, FCC-hh. Similar to LHC, this would be a circular collider with a significantly larger circumference of 100km and colliding protons at a centre of mass energy of 100TeV. Proton collisions at such high energies lead to a large amount of collision debris in the experimental insertion regions (EIR) of the accelerator. The collision debris impacts the elements of the accelerator causing long term damages, like deterioration of organic materials and superconductors, as well as instantaneous effects, like quenching of the superconducting magnets. This thesis studies the impact of the collision debris in the high-luminosity EIR of FCC-hh. For this purpose Monte Carlo simulations have been performed with the FLUKA code. Quantities like linear power distribution, peak power density, integrated dose and displacements per atom are studied for the elements of the EIR for both, horizontal and vertical crossing schemes. Mitigation strategies are developed for decreasing the impact on the magnets. With those mitigation strategies, both the absorbed power and the peak power density, are below the critical values for all the magnets. The displacements per atom benefited as well from the mitigation strategies, but still require further analysis. The cryogenic system could evacuate the deposited power on the cold masses and the magnets are protected against the risk of quenching. The peak power density remains below 8mW/cm$^{3}$, which is reassuring. As for the integrated dose on the insulator, the situation improved significantly but there are still few magnets where the design limit of 30 MGy is exceeded. This rather conservative limit is expected to rise up to 100 MGy with the use of more resistant materials. In this case, the accumulated dose would be acceptable for all the magnets of the EIR, with one exception. Further mitigation measures should be conceived for this magnet