Choose timezone
Your profile timezone:
Investigations of the bellow failure from LHC triplet to the left of Point 8
→
Europe/Zurich
30/7-018 - Kjell Johnsen Auditorium (CERN)
Description
Presentation by Mickaël Crouvizier (EN-MME-MM)
Abstract:
On the 17th of July 2023, the LHC beams were dumped after only a few minutes in collision, due to a radiofrequency interlock caused by an electrical perturbation. Several superconducting magnets around the LHC quenched. Among these magnets were the inner triplet magnets located to the left of Point 8 (LHCb), which play a crucial role in focusing the beams for the LHCb experiment. This led to a leak in the vacuum vessel of the inner triplet and thus forced the stop of LHC operation. A race against time started to avoid a complete warm-up of the affected LHC sector that would have put an end to the LHC physics program for 2023. A 10 days delay was given!
Prior inspection immediately after the failure included radiography, vibration analysis and endoscopy, which enabled the localization of the leak at an edge-welded bellow. The teams who intervened succeeded in record time to replace the bellow, and also took the opportunity to inspect all interconnections related to the inner triplet. In parallel, further investigations were carried out by EN/MME/MM to characterize the extracted bellow to find the root causes. A large variety of techniques, all present in the section, were used to conduct an in-depth analysis: X-ray tomography, electron and optical microscopy. Welding configuration, material soundness, fractographic interpretation and phase analysis are some of the elements closely scrutinized.
Following the results of this comprehensive analysis, a consolidation of the LHC Inner Triplets edge welded bellows was written and approved for LS3.
