Engineering topics

Ferracin, P.

Publications and source records attributed to Ferracin, P..

28 records · Page 2

DOE OSTI2023

An Initial Look at the Magnetic Design of a 150 mm Aperture High-Temperature Superconducting Magnet With a Dipole Field of 8 to 10 T

High-temperature superconducting REBa 2 Cu 3 O 7-$x$ (rebco) conductors have the potential to generate a high magnetic field over a broad temperature range. The corresponding accelerator magnet technology, still in its infancy, can be attractive for future energy-frontier particle colliders such as a multi-TeV muon collider. To help develop the technology, we explore the requirements and potential characteristics of a rebco magnet, operating at 4.2 or 20 K, with a dipole field of 8-10 T in a clear aperture of 150 mm. We use the canted cos $\theta$ magnet configuration to reduce the electromagnetic stresses on the conductors. We present the resulting dipole fields, field gradients for combined-function cases, conductor stresses, magnet dimensions and conductor lengths. We also discuss the conductor performance that is required to achieve the target dipole field at 4.2 and 20 K. In conclusion, the information can provide useful input to the development of rebco magnet and conductor technology for collider-ring magnets in a muon collider.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2023

A Novel Design for Improving the Control on the Stainless-Steel Vessel Welding Process for Superconducting Magnets

Stainless steel vessels see widespread use in superconducting magnets for particle accelerator applications. Their function varies in different magnet designs: they always provide the necessary liquid helium containment, but in some cases are also used to provide azimuthal prestress and can also be welded to the magnet end plate to provide additional longitudinal stiffness. A magnet designed with the bladder and key technology does not rely on the structural role of the vessel. They are structurally supported using azimuthally prestressed aluminum shells, and the longitudinal constraint by rods. In this case, the magnet designer would generally like to minimize the interaction between the magnet and the stainless-steel vessel and to minimize the coil stress variation due to the vessel. The stress state in the vessel and in the coil is a function of the circumferential interference, defined as the vessel azimuthal length minus the magnet circumference. The vessel and the magnet azimuthal length machining tolerances are relatively large resulting in significant stress variations in the superconducting coils. In this paper we introduce an interference control shim, which can significantly limit the stress variation of the coils for a given variation of the interference. The effectiveness of the interference-control shim is evaluated numerically on the MQXF, the low-β quadrupole for the High Luminosity LHC.

43 PARTICLE ACCELERATORS↗

DOE OSTI2023

Applied Metrology for the Assembly of the Nb3Sn MQXFA Quadrupole Magnets for the HL-LHC AUP

The US HL-LHC Accelerator Upgrade Project (AUP) is building Nb3Sn quadrupole magnets, called MQXFA, with plans to install 16 of them in the HL-LHC Interaction Regions. Variability in coil size must be dealt with at the assembly level, which requires timely and repeatable measurement of each coil. In this paper we will present the methodology used for coil measurements and the geometrical size data for the coils that have been measured thus far. We will also show the coil measurements of 8 coils before and after cold test. The Leica AT960-MR laser tracker with Spatial Analyzer software acquired to achieve these measurements has been used elsewhere in the project to great effect.

43 PARTICLE ACCELERATORS↗

DOE OSTI2022

High-Field Design Concept for Second Interaction Region of the Electron-Ion Collider

Efficient realization of the scientific potential of the Electron Ion Collider (EIC) calls for addition of a future second Interaction Region (2nd IR) and a detector in the RHIC IR8 region after the EIC project completion. The second IR and detector are needed to independently cross-check the results of the first detector, and to provide measurements with complementary acceptance. The available space in the existing RHIC IR8 and maximum fields achievable with NbTi superconducting magnet technology impose constraints on the 2nd IR performance. Since commissioning of the 2nd IR is envisioned in a few years after the first IR, such a long time frame allows for more R&D on the Nb₃Sn magnet technology. Thus, it could provide a potential alternative technology choice for the 2nd IR magnets. Presently, we are exploring its potential benefits for the 2nd IR performance, such as improvement of the luminosity and acceptance, and are also assessing the technical risks associated with use of Nb₃Sn magnets. In this paper, we present the current progress of this work.

43 PARTICLE ACCELERATORS↗

DOE OSTI2022

Analysis of MQXFA07 Test Non-Conformity

MQXFA07 did not meet acceptance requirement during vertical test. This report presents the analysis of MQXFA07 components related to the limited test performance, and the damage mechanism as it was understood by the MQXFA team.

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 OSTI2022

Towards 20 T Hybrid Accelerator Dipole Magnets

We report the most effective way to achieve very high collision energies in a circular particle accelerator is to maximize the field strength of the main bending dipoles. In dipole magnets using Nb-Ti superconductor the practical field limit is considered to be 8-9 T. When Nb 3 Sn superconductor material is utilized, a field level of 15-16 T can be achieved. To further push the magnetic field beyond the Nb 3 Sn limits, High Temperature Superconductors (HTS) need to be considered in the magnet design. The most promising HTS materials for particle accelerator magnets are Bi2212 and REBCO. However, their outstanding performance comes with a significantly higher cost. Therefore, an economically viable option towards 20 T dipole magnets could consist in an “hybrid” solution, where both HTS and Nb3Sn materials are used. We discuss in this paper preliminary conceptual designs of various 20 T hybrid magnet concepts. After the definition of the overall design criteria, the coil dimensions and parameters are investigated with finite element models based on simple sector coils. Preliminary 2D cross-section computation results are then presented and three main layouts compared: cos-theta, block, and common-coil. Both traditional designs and more advanced stress-management options are considered.

43 PARTICLE ACCELERATORS↗

DOE OSTI2022

Assembly and Pre-Loading Specifications for the Series Production of the Nb 3 Sn MQXFA Quadrupole Magnets for the HL-LHC

We report the High Luminosity LHC (HL-LHC) Project is planning to install 16 cold-masses made with Nb 3 Sn quadrupole magnets in the LHC Interaction Regions to significantly increase its luminosity. Half of these cold masses are fabricated at BNL, FNAL, and LBNL under the US Accelerator Research Program (AUP). Each cold mass includes two identical Nb 3 Sn quadrupole magnets, called MQXFA with a magnetic length of 4.2 m. Currently, the AUP project has completed the fabrication and test of the first 5 pre-series magnets, and is working on the following 16 magnets for the series production. The brittleness and strain sensitivity of the Nb 3 Sn superconducting material requires a careful definition of the allowable maximum stress in the windings during magnet assembly and pre-load, and a tight control of their variation within the whole coil length. Therefore, a series of assembly and pre-load specifications have been defined with the goals of minimizing the risk of conductor degradation and providing the mechanical support required to reach the nominal current during powering. In this paper we present the specifications defined for the MQXFA magnets and applied during the different assembly phases and during the pre-load process of the first 5 pre-series magnets.

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 OSTI2020

On the mechanical behavior of a Nb 3 Sn superconducting coil during a quench: Two-dimensional finite element analysis of a quench heater protected magnet

New high-field accelerator magnets based on $Nb_3Sn$ superconductors are pushing the boundaries of magnet design and quench protection towards new limits. While their large stored energies and current densities result in a very challenging scenario for magnet protection, their great electromagnetic forces create also new requirements in terms of magnet design and stress management techniques. Furthermore, the strain sensitivity of $Nb_3Sn$ cables turns the electro-mechanical limits of the conductor into a parameter of the highest importance, where conductor degradation becomes a critical aspect in magnet operation. The coupling of all the above-mentioned considerations during quench is a case of special interest that adds further complexity to the design of $Nb_3Sn$ magnets. The objective of this paper is to provide a complete two-dimensional investigation of the coil and magnet structure mechanics during a quench event. Here, the analysis is performed using a combination of finite element codes that provide the necessary input for the mechanical study. The core of the modelling strategy relies on a thermal-electric model, whose results are directly used as loads in the mechanical simulation. In doing so, the stress evolution during and after a quench is obtained. We focus for this time in the analysis of a quench heater protected magnet, where dynamic effects are of less importance in contrast to other protection systems like CLIQ.

43 PARTICLE ACCELERATORS↗