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At least 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Magnetic and Mechanical Design of a 15-T Large Aperture Dipole Magnet for Cable Testing

© 2019 IEEE. A large aperture Nb 3 Sn dipole is proposed to replace the magnet assembly of EDIPO, which was irreversibly damaged in 2016. The goal is to generate a background field of 15 T at 4.2 K in a clear aperture of approximately 100×150 mm 2 and over a uniform length of 1000 mm in order to test superconducting cables for both fusion and high-energy physics applications. The magnet features a block-type coil design wound with wide Rutherford cable (two alternative coil cross sections are considered) and supported by a mechanical structure based on keys-and-bladders technology. In the end regions, the coils tilt up (flare) through a hard-way bend of the cables to provide room for the test well, following a layout already adopted in the LBNL HD2 and CERN-CEA FRESCA2 magnets. The two considered coil design alternatives aim at minimizing the mechanical stress in the coil windings. One coil pack design makes the use of two double pancake coils per pole, whereas the other alternative features three double pancakes per pole. Both design options are presented focusing on the results of numerical computations carried out with finite-element models to investigate peak stresses in the coils during room-temperature pre-loading, cool down, and powering.

Sarasola, Xabier (ORCID:0000000324306939)↗
DOE OSTI2019

Magnetic analysis of the MQXF quadrupole for the high-luminosity LHC

The high-luminosity upgrade of the Large Hadron Collider (HL-LHC) requires new high-field and large-aperture quadrupole magnets for the low-beta inner triplets (MQXF). The U.S. HiLumi-LHC Accelerator Upgrade and CERN are jointly developing a 150-mm aperture Nb3Sn magnet. Due to the large beam size and orbit displacement in the final focusing triplet, MQXF has challenging field quality targets at collision energy. Magnetic measurements have been performed both at ambient and cryogenic temperatures in the four short models that were built and tested. This paper presents the magnetic analysis, comparing field measurements with the expectations and the field quality requirements. Furthermore, the analysis is focused on the geometrical harmonics and iron saturation effect, including three-dimensional effects and transfer function repeatability. Additionally, ersistent currents and dynamic effects are also discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Vertical Magnetic Measurements of the First Full-Length Prototype MQXFAP2 Quadrupole for the LHC Hi-Lumi Accelerator Upgrade Project

This paper reports the commissioning of the vertical magnetic measurement system and the room temperature (warm) and cryogenic (cold) magnetic field measurements of the first full-length (4.2 m) quadrupole built by the U.S. Accelerator Upgrade Project (AUP) (formerly the LARP collaboration) for the high luminosity upgrade of the Large Hadron Collider at CERN. The magnet, designated MQXFAP2, is a prototype preceding production for the AUP which will provide ten sets of 8.4-m superconducting insertion region quadrupoles for the Hi-Lumi Upgrade. The quadrupoles will be built by assembling two 4.2-m magnets in a single cryostat. Agreement between Brookhaven National Laboratory's (BNL's) and Lawrence Berkeley National Laboratory's (LBNL's) warm measurement data has indicated that the upgraded vertical magnetic measurement system at Brookhaven National Laboratory is ready for MQXFA magnet production testing. Lastly, the cold magnetic measurement has been performed and preliminary data analysis has been conducted.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Mechanical Performance of the First Two Prototype 4.5 m Long Nb$_3$Sn Low-$β$ Quadrupole Magnets for the Hi-Lumi LHC Upgrade

The U.S. High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) team is collaborating with CERN in the design and fabrication of the first 4.5 m long MQXFA magnets, a 150 mm aperture high-field Nb$_3$Sn quadrupole magnet that uses the aluminum shell-based bladder-and-key technology. The first two prototype magnets, MQXFAP1 and MQXFAP2, were assem-bled and tested while the first pre-series structure (MQXFA03) was in fabrication. This paper summarizes the mechanical perfor-mance of these prototype structures based on the comparison of measured strain gauge data with finite element model analyses from all load steps to powering. The MQXFAP1 magnet almost reached ultimate current before a short to ground was detected and the test was stopped. The MQXFAP2 magnet experienced a low training performance due to a fractured aluminum shell. MQXFAP1b was rebuilt with a new replacement coil, but an old coil limited the magnet from achieving the ultimate current. The mitigations and analyses of these prototype magnets are discussed in the context of the transition to pre-series production.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Characterization of NbTi busbar for HL LHC Interaction Region Quadrupoles

The US Accelerator Upgrade for the HiLumi-LHC (US-HL-LHC AUP) project and CERN are designing and fabricating superconducting quadrupole magnets for the interaction regions of the High Luminosity Large Hadron Collider (HLLHC). The triplet is made of three optical elements: Q1, Q2, and Q3. The Nb3Sn quadrupole magnets operate in superfluid He at 1.9 K with a nominal field gradient of 132.6 T/m. The three inner triplet elements are connected together with superconducting buses. The design and fabrication of the through and local buses is carried out at Applied Physics and Superconducting Technology Division (APS-TD) at Fermilab (FNAL). This paper reports the characterization of the bus-bar thermoelectric properties. The bus was tested with a short Nb3Sn magnet (MQXFS1e) in the vertical test facility of the APS-TD at FNAL. The test demonstrated that the bus design is adequate since no spontaneous quench took place up to 17.87 kA current value. Quench propagation velocities were investigated over a range of currents that is typical for accelerator superconducting magnets. Temperature margins were found above that required for the Hi- Lumi triplet bus. The design guarantees the protection of the bus at operational current value according to the quench detection voltage threshold (100 mV) established for the Hi-Lumi LHC interaction region.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Test Results of the First Two Full-Length Quadrupole Magnets for the LHC Hi Lumi Upgrade

The future high luminosity (Hi-Lumi) upgrade of the Large Hadron Collider (LHC) at CERN will include eight (plus two spares) 8.4 m-long cryostatted cold masses which will be components of the triplets for two LHC insertion regions. Each cold mass will consist of two 4.2 m long Nb 3 Sn high gradient quadrupole magnets, designated MQXFA, with aperture 150 mm and operating gradient 132.6 T/m, for a total of twenty magnets. Before assembling and testing the final cold masses at Fermilab, the twenty component quadrupoles will be tested first at the ver-tical superconducting magnet test facility of the Superconducting Magnet Division at Brookhaven National Laboratory (BNL), in superfluid He at 1.9 K and to 18.0 kA, to meet LHC operational requirements. The first two full-length prototype quadrupole magnets, MQXFAP1 and MQXFAP2, have been tested at BNL. This paper reports on the quench test and training results of these magnets, and also the retest of the first prototype, rebuilt and designated as MQXFAP1b. We note the test results of these magnets will be important for validating the MQXFA design.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Design of a High Toughness Epoxy for Superconducting Magnets and Its Key Properties

Nb 3 Sn accelerator magnets are poised to enable the luminosity upgrade of the Large Hadron Collider (LHC) at CERN, improving its potential for exploring physics beyond the standard model of particle physics. The prototype Nb 3 Sn magnets consistently need 10–25 quenches to achieve their best performance. A hypothesis is that the long training of these magnets may at least be partially induced by epoxy cracking and bonding failures. In 2018, we showed that several existing epoxies have a higher toughness and less tendency to crack at low temperatures than CTD-101K, the epoxy resin with which almost all Nb 3 Sn accelerator magnets have been impregnated. Here we explore a new high toughness formulation for reducing quench training of Nb 3 Sn accelerator magnets, through combining two amine curing agents to achieve a good glass transition temperature (T g ), adding a viscosity reducer to achieve low viscosity, and experimenting a coupling agent for improved bonding strengths. In this work, we report results of comprehensive materials tests, including thermal shock, tensile, compressive, shear tests, viscosity and T g tests.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

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

The U.S. Hi-Lumi LHC Accelerator Upgrade Project (AUP) and CERN have joined efforts to develop high field quad-rupoles for the Hi-Lumi LHC upgrade. The US national laborato-ries 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 in-tegrated 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 per-formed 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 de-signed and added to better center the warm bore tube which con-tains 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.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Mechanical Comparison of Short Models of Nb$_3$ Sn Low-$\beta$ Quadrupole for the Hi-Lumi LHC

MQXF is the Nb 3 Sn Low-β quadrupole magnet that the HL-LHC project is planning to install in the LHC interaction regions in 2026 to increase the LHC integrated luminosity. The magnet will be fabricated in two different lengths: 4.2 m for MQXFA, built in the US by the Accelerator Upgrade Project (AUP), and 7.15 m for MQXFB, fabricated by CERN. In order to qualify the magnet design and characterize its performance with different conductors, cable geometries and pre-load configurations, five short model magnets, called MQXFS, were fabricated, assembled and tested. We compare the mechanical behavior of short model magnets using experimental data and new numerical models that take into account the measured coil sizes as a function of position.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Test Results of the First Pre-Series Quadrupole Magnets for the LHC Hi-Lumi Upgrade

The future high luminosity (Hi-Lumi) upgrade of the Large Hadron Collider (LHC) at CERN will include eight (plus two spares) 10.2 m-long Cryo-assemblies which will be components of the triplets for two LHC insertion regions. Each cold mass in the Cryo-assemblies will consist of two 4.2 m-long Nb 3 Sn high gradient quadrupole magnets, designated MQXFA, with aperture 150 mm and operating gradient 132.2 T/m, for a total of twenty magnets. Before assembling and testing the final cold masses at Fermilab, the component quadrupoles are being tested first at the vertical superconducting magnet test facility of the Superconducting Magnet Division (SMD) at Brookhaven National Laboratory (BNL), in superfluid He at 1.9 K and up to 18.0 kA, in accordance with operational requirements of the LHC. The tests of the first two full-length prototype quadrupole magnets MQXFAP1 and MQXFAP2 at BNL have been reported previously. The first two pre-series magnets, the first two that will be used in the LHC, have also now been tested. This paper reports on the quench test and training results of these two magnets. The test results of these magnets will be important for validating the final MQXFA design for operational magnets.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Field quality of the 4.5 m-long MQXFA pre-series magnets for the HL-LHC Upgrade as observed during magnet assembly

We report that 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 Nb 3 Sn 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 magnetic 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 Nb 3 Sn 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 Nb 3 Sn magnets and on the optimization of field quality of accelerator magnets based on the wind-and-react Nb 3 Sn technology.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Application of Distributed Fiber Optic Strain Sensors to LMQXFA Cold Mass Welding

The future High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN will include the low-beta inner triplets (Q1, Q2a/b, Q3) for two LHC insertion regions. The Q1, Q3 components consist of eight 10 m-long LMQXFA cryo-assemblies fabricated by the HL-LHC Accelerator Upgrade Project. Each LMQXFA Cold mass contains two Nb 3 Sn magnets connected in series. A stainless-steel shell is welded around the two magnets before the insertion into the cryostat. There is a limit on how much coil preload increase induced by the shell welding is allowed. Distributed Rayleigh backscattering fiber optics sensors were used for the first time to obtain a strain map over a wide area of a Nb 3 Sn magnet cold mass shell. Finally, data were collected during welding of the first LMQXFA cold mass and the results confirm that the increase of the coil pole azimuthal pre-stress after welding do not exceed requirements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

The Challenges and Solutions of Meeting the Assembly Specifications for the 4.5 m Long MQXFA Magnets for the Hi-Luminosity LHC

The U.S. High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) has, in the recent years, developed assembly specifications for the 4.5 m long MQXFA magnets, which are 150 mm aperture high-field Nb 3 Sn low-β quadrupole magnets that are being built for the CERN Hi-Luminosity LHC (HL-LHC) upgrade. While the specifications were based on lessons learned from the LHC Accelerator Research Program (LARP) effort and the MQXFS and MQXFA prototype magnets, the experience gained from having both MQXFA07 and MQXFA08 magnets not meeting performance specifications during cold testing actually catalyzed a better understanding of the impact of the target assembly specifications and a subsequent refinement of the same. This paper summarizes a body of assembly data from the Pre-Series (MQXFA03-MQXFA07) and Series magnets (MQXFA08-MQXFA11) that have been built to date, and discusses the processes employed to successfully face the challenge of ensuring that the assembly specifications are met for the duration of the project.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Analysis of the Mechanical Performance of the 4.2-m-Long MQXFA Magnets for the Hi-Lumi LHC Upgrade

Under the U.S. High Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP), the 150 mm bore, high-field Nb 3 Sn low-{eta}_MQXFA quadrupole magnets are being fabricated, assembled and tested, in the context of the CERN Hi-Luminosity LHC (HL-LHC) upgrade. These magnets have 4.2 m magnetic length and 4.56 m long iron yoke. To date, eight MQXFA magnets have been tested. One of the magnets additionally underwent a successful endurance test with 40 triggered quenches, and two magnets did not perform as expected. This work summarizes for the first time the available strain gauge data from eight identical Nb 3 Sn MQXFA tested magnets, focusing on the endurance test, and on a possible cause of underperformance of the two magnets that did not pass the vertical test. Here we applied methods to prevent this from happening in future MQXFA magnets, which shown to be effective for last two tested magnets.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Effect of CLIQ on Training of HL-LHC Quadrupole Magnets

The high-luminosity LHC upgrade requires stronger than LHC low-beta quadrupole magnets to reach the luminosity goals of the project. The project is well advanced and HL-LHC quadrupole magnets are currently being commissioned in US Labs (MQXFA magnets) and CERN (MQXFB magnets). Those are the first Nb 3 Sn magnets to be used in any large particle accelerator. At development stages, many Nb 3 Sn accelerator sub-scale models showed relatively slow training and MQXFA magnets were projected to have low tens of quenches before reaching operational field. Recently it was shown that dedicated capacitor-based de-vices can affect Nb 3 Sn magnet training, and it was suggested that CLIQ, a capacitor-based device intended for quench protection, can do too. Here, the present paper investigates effects on training likely induced by CLIQ, using the base fact that only half the coils in a quadrupole experience upward current modulation at quench because of capacitor discharge. The study encompasses all MQXFA production magnets trained at BNL to date. No other high-statistics data from identical magnets (series) with CLIQ protection exist so far. Implications and opportunities stemming from data analysis are discussed and conclusions drawn.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Fermilab's Horizontal Test Stand Upgrade Overview and Commissioning

Cryo-assemblies with the Nb 3 Sn MQXFA low-beta quadrupoles for the High Luminosity LHC (HL-LHC) upgrade will be tested at Fermilab's magnet test facility. A total of 10 cryo-assemblies will be delivered to CERN within the US HL-LHC Accelerator Upgrade Project (AUP). The horizontal test stand at Fermilab already has been used for testing the existing LHC inner-triplet quadrupoles, but the stand and corresponding electrical and cryogenic sub-systems were not operational for more than a decade. In order to restore the test stand functions and meet the design and test requirements for the HL-LHC magnets, the existing horizontal test facility at Fermilab underwent a significant refurbishment of the cryogenic and mechanical components. Most of the upgrades were completed and verified during so called zero-magnet test by late 2020, and then final commissioning of the upgraded horizontal test stand was completed during the first cryo-assembly test in 2023. These tests verified the major cryo-mechanical installations, as well as the basic test stand operations, including controlled cooldown and operation at 1.9 K, magnet protection and process controls. Here, in this paper, overview of the Fermilab's horizontal test facility upgrade and commissioning of these upgrades are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Mechanical Design of the Interaction Region Dipole B1pF for Electron Ion Collider

Here, the Electron-Ion Collider (EIC), planned for construction at Brookhaven National Laboratory, will consist of two intersecting beams of intense electrons and high-energy protons or heavier atomic nuclei. The collider will need many demanding components, including high field superconducting magnets for the Interaction Region (IR). It has been decided that a prototype of one such magnet, the B1pF dipole, shall be built, to validate design choices common to all Rutherford cable dipole and quadrupole IR magnets. B1pF is one of several high field magnets in the interaction region whose design is based on the 15.1 mm wide NbTi cable, a cable like the one used in the main dipole coil of the Large Hadron Collider (LHC) at CERN. The current design is based on a single layer coil with an inner diameter of 300 mm and magnetic length of ~3 m which generates a magnetic field at the center of the magnet of about 3.7 T at a current of ~11 kA at design. This paper presents the mechanical design of the B1pF dipole magnet, and the R&D effort associated with the development of the prototype, including tests for successfully winding and curing coils of the needed configuration into proper structural and magnetic elements, and including a multilayer magnetic return yoke which meets field requirements while providing an initial reduced structure suitable for operational testing in an existing test facility.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Status of the Top Plate and Anticryostat for High Field Cable Test Facility at Fermilab

Fermi National Accelerator Laboratory (Fermilab) is currently constructing a new High Field Vertical Magnet Test Facility (HFVMTF) designed for testing High Temperature Superconducting (HTS) cables under high magnetic fields. This facility is expected to offer capabilities similar to those of EDIPO at PSI and FRESCA2 at CERN. The background magnetic field of 15 T will be generated by a magnet supplied by Lawrence Berkeley National Laboratory. The primary function of HFVMTF will be to serve as a superconducting cable test facility, facilitating tests under high magnetic fields and a broad spectrum of cryogenic temperatures. Additionally, the facility will be utilized for testing high-field superconducting magnet models and demonstrators, including hybrid magnets, developed by the US Magnet Development Program (MDP). This paper provides a comprehensive description of the current status of two pivotal components of the facility: the Top/Lambda Plates Assembly and the Anticryostat for the Test Sample Holder. The latter will serve as a principal interface component connecting cable test samples with the facility's cryostat.

43 PARTICLE ACCELERATORS↗