Summary
- The studied HL-LHC BGI design with steel cathode and NEG coated ceramic cathode were explained.
- The models with NEG coated (50 Ω, 300 Ω and 1 kΩ) ceramic cathode showed beam-induced RF heating over 260 W because of the broadband impedance contribution.
- The model with steel cathode has resonant peaks as expected but it is better than the former scaled SPS-like design. The resonant peaks must be kept away from the beam harmonics in the case of steel cathode usage. (slide 6)
- The RF absorbers (NEG coated ceramics) are under investigation as mitigation measures. The coating material can be titanium since NEG was changed to titanium for the wire scanner study (bake-out temperature issues). If we keep the coating surface resistivity as the same, the longitudinal impedance response will be the same regardless of the NEG or titanium. (slide 11-12)
- There is not much space for the RF coupler if it is considered for the mitigation of the resonant peaks. In that case, the study priority will be given to the resistively coated ceramics.
- The magnet aperture is not confirmed yet. This may effect the BGI tank design. In that case, new simulation iterations will start. Information will be provided by BI-ML Team.
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Summary added by H. Bursali on 22.07.2025
