109th Impedance Working Group (AoB, Chirstmas gathering)

Tuesday 16 Dec 2025, 15:30 → 17:15 Europe/Zurich

6/2-004 (CERN)

Carlo Zannini (CERN), Christine Vollinger (CERN)

Minutes of 109^th Impedance Working Group meeting

Date: 16/12/2025

Present: Chiara Antuono, Sergio Calatroni, Elena de la Fuente García, Miguel Díaz Zúmel, Antonia Huber, Patrick Krkotic, Elena Macchia, Nicolas Mounet, Hermann Pommerenke, Julian Sonpar, Christine Völlinger, Carlo Zannini.                                                                                                                                                                                         

 

Comment to ECR 3284880 on LHC experiments unshielded bellows (Hermann)

Hermann lists the unshielded bellows in Run3, and the ones that will be unshielded in Run4.

For instance, in Alice, 4 bellows are unshielded in Run3; in Run4, 6 bellows will be unshielded and there will be 2 DRFs.

He computes and quantifies the total increase of the LHC impedance due to the more unshielded bellows in Run4.

Eff. imag. impedance increases by 0.6 mΩ = 0.75 % of LHC impedance (~ 80 mΩ)

Discussion

When asked about other impedance contributors, Christine replies that the IWG keeps a look into all the impedance contributors.

15:30 → 15:50 AoBs

Speakers: Carlo Zannini (CERN), Christine Vollinger (CERN), Hermann Pommerenke (CERN), Ivan Karpov (CERN)

2025-12-16-IWG-LHC-experiments-unshielded-bellows.pdf

2025-12-16-IWG-LHC-experiments-unshielded-bellows.pptx