Speaker
Description
The Barrel Timing Layer and Tracker Support Tube (BTST) is a 2.4-meter diameter, 5.3-meter long composite sandwich structure designed to provide primary mechanical support for the Barrel Timing Layer, Outer Tracker, and Inner Tracker detectors of the CMS detector for the HL-LHC. This presentation provides updates on repair campaign at CERN, simulation learnings and repair validation testing conducted to address findings from manufacturing quality control and road accident. Key learnings from the development of accurate material models—reflecting as-manufactured properties and realistic boundary conditions necessary to simulate worst-case loading scenarios expected during installation into the calorimeter with the temporary support structure (Eiffel tower)—are discussed. The learnings from the on-site repair campaign and details of the methodology used for affecting the repairs at CERN are presented. The metrology techniques used for validation of the BTST, and results from the QA/QC of repairs and mechanical and thermal load testing to validate the structure for use in the HL-LHC are presented. This talk serves as a follow-up to previous presentations at FTDM 2024 and FTDM 2025, which covered the initial design, simulation, and manufacturing process of the BTST as well as the simulation and prototyping for the repair campaign at CERN.