Fabrication of First 4-m Coils for the LARP MQXFA Quadrupole and Assembly in Mirror Structure

Anderssen

et al. 2018

Self Cite

The LHC Accelerator Research Program (LARP), in collaboration with CERN and under the scope of the high luminosity upgrade of the Large Hadron Collider, is in the prototyping stage in the development of a 150 mm aperture high-field Nb 3 Sn quadrupole magnet called MQXF. This magnet is mechanically supported using a shell-based support structure, which has been extensively demonstrated on several R&D models within LARP, as well as in the more recent short (1.2 m magnetic length) MQXF model program. The MQXFA magnets are each 4.2 m magnetic length, and the first mechanical long model, MQXFA1M (using aluminum surrogate coils), and MQXFA1 prototype magnet (the first prototype with Nb 3 Sn coils) have been assembled at LBNL. In this paper, we summarize the tooling and the assembly processes, and discuss the mechanical performance of these first two assemblies, comparing strain gauge data with finite element model analysis, as well as the near-term plans for the long MQXF magnet program.

Section: Introductionmentioning

confidence: 99%

Fabrication and Assembly Performance of the First 4.2 m MQXFA Magnet and Mechanical Model for the Hi-Lumi LHC Upgrade

Cheng

Anderssen

et al. 2018

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“…The pins have been changed to non-magnetic ones in the current coil and magnet production. Holik et al studied the coil size variations before but the study was not directly linked to measured harmonics or its variations [14]. In order to find the relationship, Coordinate-measuring machine (CMM) coil size data for the coils used in magnet MQXFA03 were provided by D. Cheng at LBNL [15].…”

Section: Possible Relationship Between Coil Size Variations and Harmonics Variationsmentioning

confidence: 99%

Magnetic Field Measurements of First Pre-series Full-Length 4.2 m Quadrupole MQXFA03 Using PCB Rotating Coils for the Hi-Lumi LHC Project

Song

Amm

et al. 2021

Self Cite

The U.S. Hi-Lumi LHC Accelerator Upgrade Project (AUP) and CERN have joined efforts to develop high field quadrupoles for the Hi-Lumi LHC upgrade. The US national laboratories in the AUP project will deliver 10 magnets and each cryostat has two 4.2 m high gradient quadrupoles in it. These magnets are made of Nb3Sn conductors, with large aperture (150 mm) and integrated gradient of 556.9 T. This paper reports on magnetic measurements performed during the vertical test at Brookhaven National Laboratory (BNL) in 2019-2020. A warm measurement Z-Scan (+/-15 A) with 42 Z-positions before cool-down was performed at BNL. The results were directly compared to field data measured at LBNL during magnet assembly. Measured harmonics and magnetic center offsets (ΔX and ΔY) have provided timely and informative diagnostics on the magnet structure's shape at both warm and cold temperatures. A new centering fixture was designed and added to better center the warm bore tube which contains the rotating coil probe. After the quench training to 16.47 kA was achieved, a complete set of cold measurements (Z-Scan at 16.47 kA and I-Scan from 960 A to 16.47 kA and back to 960 A) was made. Periodic axial variation of allowed and nonallowed harmonics was observed which is related to the coil radial and/or mid-plane variations along the magnet axis. Overall, the average harmonics in the straight section are within the required field boundaries.

“…The reacted coils are then impregnated with epoxy resin. Details on the coil fabrication are reported in [5].…”

Section: Introductionmentioning

confidence: 99%

Field Quality of the 4.5-m-Long MQXFA Pre-Series Magnets for the HL-LHC Upgrade as Observed During Magnet Assembly

Wang

Yahia

et al. 2022

The U.S. High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) is developing MQXFA magnets, a series of 4.5 m long 150 mm aperture high-field Nb3Sn quadrupole magnets for the HL-LHC upgrade at CERN. Five pre-series magnets, MQXFA03 through MQXFA07, have been developed. During the magnet assembly stage, we perform magnetic measurements on the coil-pack sub-assembly and magnets after loading to track the field quality for two purposes. First, it serves as a quality assurance tool to check if the magnet field quality is on track to meet the acceptance criteria. Magnetic measurements are used to understand if magnetic shims are needed to compensate low-order field errors and to meet the field quality targets. Second, the measurements during the assembly stage can also help understand the field quality, especially the geometric field errors, for Nb3Sn accelerator magnets. Here we summarize the measurement results of the pre-series MQXFA magnets, including the magnetic axis and twist angle. The results will provide useful feedback for the series production of Nb3Sn magnets and on the optimization of field quality of accelerator magnets based on the wind-and-react Nb3Sn technology.