By Nicolas Heredia Garcia, Aleksandra Onufrena, Antonio Perin, and Davide Bozzini

The SQXL cryogenic line, an essential component of the HL-LHC IT String, has recently undergone an additional series of commissioning tests in standalone mode without the magnets.

The test slot was carefully scheduled to align with both the IT String and SM18 planning, ahead of the cryogenic shutdown. This testing phase included commissioning of the Cold Compressor (CC) and its control logic, which was upgraded to better adapt to variable heat loads in the magnets. Moreover, tests were performed to validate the cooling capacity of the system and the heat loads were measured following the repairs of non-conforming lines of the Proximity Cryogenics Distribution System (PCDS). After completing the tests, a series of leak checks was carried out.

The results from the test campaign are currently being analysed in detail to complete the characterisation of the cryogenic system. Following commissioning phase 1C, system studies and mechanical activities – such as preparation of the jumper interfaces – will be performed to ready the SQXL for connection to the IT String magnets and cold powering. Once all the systems have been connected, the second phase of commissioning will start, to validate the full conformance and performance of the HL-LHC IT String.

You can read more about the advancement in the HL-LHC IT String in the latest HL-LHC Collaboration Board Newsletter!