A semi-passive beam dilution system for the FCC-ee collider

Abstract The operation modes for the proposed FCC-ee collider foresee a very small beam spot size and stored energies of up to 20.6 MJ in Z production. This necessitates dedicated dumping system. To reduce complexity system as well minimize required space, an optimized, semi-passive has been designed is presented here. dilution done with defocusing triplet structure, followed by passive diluter elements (spoilers). greatly reduces risk possible failure scenarios compared active kicker-magnet dump core itself located ${\sim}70~\text{m}$ ∼ 70 m downstream spoilers following experience gained from LHC dump. performance interaction effects responsible energy deposited spoiler, are directly related radiation length dimension device direction. Materials these have studied extensively key requirements identified using both Monte Carlo shower simulations thermo-mechanical Finite Element Analysis. Even though maximum temperature reached within working range material, induced mechanical stresses can lead material failure. Thermo-mechanical shown that transversal shape plays role magnitude result impact abrupt change. problem addressed this paper optimized solution presented.