News Topic: WP1 Project Management

Status of SM18 test benches for SC magnets and SC-link, and test plan for 2024

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By Gerard Willering (CERN)Franco Mangiarotti (CERN)

Test bench requirements for the HL-LHC

In the last years, the horizontal test benches have been modified to accommodate the HL-LHC magnet and SC-link test program. The number of HL-LHC magnet cryoassemblies to be validated (24 magnets + 8 SC-links + spares) is much lower than for the LHC, but there are more variations in connectivity, increased current in the main magnets (from 13 kA to 18 kA), increased current in the corrector magnets (600 A to 2 kA), and the incorporation of Coupling Loss Induced Quench (CLIQ) protection units. In addition, the Nb3Sn conductor is much more susceptible to flux jumps at a low current, requiring current-dependent quench detection thresholds which are enabled by the new universal quench detection (UQDS) technology. To measure and investigate the performance of the magnets with a larger bore of 150 mm, magnetic measurement shafts, quench antennas, and anti-cryostats have been developed and produced, and are successfully in operation.

At this moment, the fully refurbished benches A2, F1, and F2 are operational thanks to the large commitment of all the different teams involved. The ongoing upgrade of the remaining two shuffling modules on benches B2 and C2 is planned to be completed by the beginning of autumn.

SM18 alongside table
Figure 1: Assembly of one Q2 cryomagnet next to the superconducting link prototype system, tested in parallel on benches F1 and F2. The table lists the bench configuration and status of all horizontal test benches. Photo by Michael Struik (CERN).

Test plan for 2024

The first batch of tested cryomagnets are destined for installation in the Inner Triplet (IT) String currently under construction in SM18, requiring 6 cryoassemblies (D1+CP+Q1+Q2a+Q2b+Q3) and one SC-link. The test of the D1 and Q2a has been completed. The Q2b and Q3 are currently in testing, with the goal of test completion by the SM18 technical stop in July. The Q3 assembly has already been tested in the US as part of the Accelerator Upgrade Program (AUP) contribution, while the effects of its transport to CERN will be verified on the SM18 test bench. The last cryoassembly tested in SM18 for the IT String will be the Corrector Package (CP), with a test starting in August. The Q1 assembly will be tested in the US before installation in the IT String.

table
Figure 2: Dashboard of the status of cryomagnets and SC-link tests for the HL-LHC. The codes in the table indicate the identification of each cryoassembly, with ‘P’ for prototype and the numbers for the series magnets. Magnets and SC-link for the String are highlighted in blue.

Test outlook

From September onwards, the main focus will be on the batch of series magnets and SC-links to test for the HL-LHC. With the current status of the benches, the test team - together with all supporting teams - is ready to perform all qualification tests, magnet performance verifications, and electrical quality assurance tests during the intense period of tests for series components.

team photo in SM18
Figure 3: SM18 test team in front of the Q2 at the fully refurbished test bench F1, ready for the intense period of testing for the series components for the HL-LHC in 2025. Photo by Marina Cavazza (CERN).

 

SM18MagnetsSC-linkIT StringAUPCLIQquenchCold powering systemsmagnet test bench