Speaker
Description
Abstract
CMS Phase-II tracker and calorimeter subassemblies are currently in production, including their complex, high-pressure CO$_2$ cooling circuits. It is mandatory to ensure that these circuits are leak-tight and safe for operation. Adhering to CERN HSE’s regulations, any pipe assembly of the CO$_2$ cooling system must undergo specific tests and certifications. Furthermore, the 10-year minimum lifetime requirement for the detector adds a significant time dimension and difficulty to the certification of materials and joining techniques, particularly with thin-walled, non-standard pipework of these detectors.
This talk will go into detail on the efforts made at CERN for testing and validating prototypes, such as welded and brazed connections, as well as proof-testing final detector subassemblies. A multi-step protocol was developed to ensure thorough testing including helium leak tests, temperature and pressure cycling, combined with high-resolution CT scanning of the parts before and after the tests.
Keywords
CERN, HL-LHC, CMS, Carbon Dioxide, Refrigeration, Quality Control, CT Scanning