By Antonio Perin (CERN)

An important step for the installation of the new HL-LHC cryogenic distribution line (QXL) was achieved during the last week of July and the first two weeks of August: the test installation of two pipe elements of QXL in the HL-LHC UR15 gallery at Point 1, carried out by the QXL contractor, Kriosystem, in collaboration with CERN teams.

The objective of this operation was to validate the procedures and techniques ahead of the installation of the first 150 m of QXL, planned for October 2025.

Following preparatory work from April to July, including the precise installation of supports to the vault of UR15, two ten-meter-long pipe elements of the QXL were, for the first time, lifted to the ceiling and connected to their supports. This delicate operation was performed successfully and was followed by the fine alignment of the two pipe elements. The next steps included welding of the internal cryogenic pipes in the interconnection and subsequent non-destructive tests, which took place over the two weeks.

This test allowed the detailed verification of the steps of the installation sequence and identification of areas requiring improvement. The lessons learnt are now being evaluated in collaboration with the contractor in view of their implementation for the forthcoming installation phase.

Figure 2. Lowering of a QXL pipe element in PM17 (left), welding of the interconnection between two QXL pipe elements (top right). Michele Sisti / CERN. Two QXL pipe elements installed in UR15 (bottom right). Antonio Perin / CERN