The continuity of the 18, 13, and 2 kA circuits of the HL-LHC magnets heavily relies on splices and electrical connections, to which it is worth devoting a special attention from the early phases. ...This spans the design of the splice or connection itself, together with the tooling and related procedure, so that the execution can reliably yield high quality results. Mindful of the history of LHC splices, robustness and reproducibility of the execution solutions are two of the fundamental parameters that have guided the technical choices made during the development phase. The number of technical solutions considered is due to the variety of possible combinations, depending on the various nature and geometry of the superconducting cables to be joined together. This wide spectrum calls for a rigorous qualification protocol, including micrography, mechanical tests before and after fatigue stress and electrical tests at room and cryogenic temperature. The article will illustrate the choices made during the development phase for the 11 selected families of splices and electrical connections, together with their qualification process, while providing results and statistics from the mechanical and electrical tests campaigns.
Fermilab is fabricating ten full length cold masses for the high-luminosity Large Hadron Collider Accelerator Upgrade Project (HL-LHC AUP). One practice assembly and one pre-series assembly have been ...completed. This paper summarizes the con-struction details. Topics include incoming inspection, bus assembly, component machining, shell forming, beam tube insertion, bus expansion loop installation, instrumentation installation, electrical testing, heat exchanger installation and final assembly welding. In-process surveys, alignment measurements and testing are presented and explained. Problems encountered during construction and their solutions are discussed.
As a Japanese contribution to the High-Luminosity Large Hadron Collider (HL-LHC) upgrade, KEK is in charge of developing the beam separation dipole cold masses. The full-scale prototype magnet ...(MBXFP1) was constructed in Hitachi and powering test at cold was conducted at KEK. After the test, the magnet was returned to Hitachi for the final assembly of the cold mass. The pressure vessel design of the cold mass was carried out by KEK in accordance with ASME code. A new design of bus leads was proposed to satisfy the requirement of flexibility as well as mechanical support and electrical insulation. Welding of the extremity pipes was challenging due to tight position tolerance. This article reports the structure, pressure vessel design, and assembly of the LMBXF prototype cold mass (LMBXFP1) including bus work, instrumentation, and welding works with geometrical measurements.
New high field and large-aperture quadrupole magnets for the low-beta inner triplets (Q1, Q2, Q3) have been built and tested as part of the high-luminosity upgrade of the Large Hadron Collider ...(HL-LHC). These new quadrupole magnets are based on Nb3Sn superconducting technology. The US Accelerator Upgrade Project (US-AUP) is producing the Q1 and Q3 Cryo-Assemblies: a pair of ∼5 m long magnet structures installed in a stainless-steel helium vessel (Cold Mass) and surrounded by cryostat shields, piping, and a vacuum vessel. This paper gives an overview of the design, production, and the results of the horizontal test of the first pre-series Q1/Q3 Cryo-Assembly.
As part of the U.S. contribution to the HL-LHC Accelerator Upgrade Project (AUP), Fermilab is designing and building cold masses suitable for use in the LHC interaction regions. The cold mass ...provides a vacuum-tight helium enclosure for the magnets. Two magnets are aligned both axially and in cross section at Fermilab based on survey and warm magnetic measurements. Bus work and instrumentation is added. A welded stainless steel vacuum-tight shell surrounds the two magnets, and the structure is prepared for insertion into the cryostat. This paper summarizes the design of the cold mass including alignment, bus work, weld details, and instrumentation.
The High-Luminosity project (HL-LHC) of the CERN Large Hadron Collider (LHC), requires low <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>* quadrupole magnets in Nb ...<inline-formula><tex-math notation="LaTeX">_\text{3}</tex-math></inline-formula>Sn technology that will be installed on each side of the ATLAS and CMS experiments. After a successful short-model magnet manufacture and test campaign, the project has advanced with the production, assembly, and test of full-size 7.15-m-long magnets. In the last two years, two CERN-built prototypes (MQXFBP1 and MQXFBP2) have been tested and magnetically measured at the CERN SM18 test facility. These are the longest accelerator magnets based on Nb <inline-formula><tex-math notation="LaTeX">_\text{3}</tex-math></inline-formula>Sn technology built and tested to date. In this paper, we present the test and analysis results of these two magnets, with emphasis on quenches and training, voltage-current measurements and the quench localization with voltage taps and a new quench antenna.
This contribution describes the experimental program already undergoing and to be completed on the High Luminosity Large Hadron Collider (HL-LHC) Inner Triplet (IT) String, an important intermediate ...milestone of the HL-LHC project at CERN. First, it describes the magnet circuits of the HL-LHC IT String. Afterwards, the different systems installed to perform the experimental program are detailed. The proposed tests are defined for the validation of the cryogenic system, the full remote alignment system, the powering system, and the protection schemes of all magnets working in unison. This strategy will allow for a verification of the integrated powering system before the final installation and commissioning in the HL-LHC's underground areas.
The busbars for the HL-LHC magnets are made of Nb-Ti/Cu conductor, the insulation system, and the auxiliary equipment to align the busbars with respect to the magnet coldmasses. This paper presents ...design options concerning the integration of the busbars inside the coldmass with a fixed point, and a reinforced insulation system for the flexible busbar part using thin PEEK tubes. Prototype splices for interconnecting Nb3Sn and Nb-Ti Rutherford cables, and round and flat 18 kA Nb-Ti cable have been produced and first test results are presented.
The HL-LHC Project currently undertaken by CERN that provides an upgrade to the existing LHC accelerator, is designed to increase the luminosity of the colliding particle bunches by a factor of at ...least five. Part of this upgrade will require the replacement of the existing groups of three superconducting LHC triplet magnets situated on each side of the ATLAS and CMS detectors with similar groups of four higher field HL-LHC triplet magnets of a new design that exploit coils manufactured with cables in Nb3Sn superconducting alloy. The HL-LHC triplet magnets require dedicated electric current feeders linking their cold masses to their cryostat vacuum vessels, thermo-electrically optimised and specifically designed to separately feed their quench protection, beam tuning and instrumentation systems with electric current. The HL-LHC instrumentation feedthrough system is similar, though containing a larger cable inventory, to that mounted on existing cryo-magnets in the LHC accelerator whereas the quench protection and beam tuning systems, both present new requirements calling for a substantially different design approach. Installed in a highly activated zone of the LHC, all three systems consequently exploit only natural heat convection to prevent the formation of condensation at their warm ends. This paper describes the functional design and thermo-electrical optimisation achieved for each of these electric current feeder systems.
About one hundred magnets of six different types shall be installed in the High Luminosity LHC (HL-LHC) in the years 2026--2028 at CERN. The magnets design, construction and test are based on CERN ...collaborations with institutes and industrial partners in USA, Spain, Italy, Japan and China. Three types of correctors are based on Nb-Ti technology and feature conductor peak fields in the 2 to 4 T range: for all of them the protoype phase has been successfully completed. The production is well advanced for the superferric correctors, and is starting for the canted cos theta correctors and for the nested correctors. The separation and recombination Nb-Ti dipoles D1 and D2, with a 4.5-6 T bore field range, are both in the prototype phase after the completion of the short model program. The most challenging magnet, the Nb 3 Sn quadrupole with conductor peak field above 11 T, is in the prototype phase at CERN and halfway through the production phase in the USA. In this paper we will give, for each type of magnet, an overview of the main achievements obtained so far and we will outline the technical points still needing validation from the prototype program.
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