High-temperature superconducting <inline-formula><tex-math notation="LaTeX">\rm{REBa}_{2} Cu_{3} O_{7-x}</tex-math></inline-formula> ( 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 <inline-formula><tex-math notation="LaTeX">\cos \theta</tex-math></inline-formula> 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. The information can provide useful input to the development of REBCO magnet and conductor technology for collider-ring magnets in a muon collider.
Magnets for a Muon Collider-Needs and Plans Bottura, L.; Accettura, C.; Amemiya, N. ...
IEEE transactions on applied superconductivity,
08/2024, Letnik:
34, Številka:
5
Journal Article
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We describe the magnet challenges for a Muon Collider, an exciting option considered for the future of particle physics at the energy frontier. Starting from the comprehensive work performed by the ...US Muon Accelerator Program, we have reviewed the performance specifications dictated by beam physics and the operating conditions to satisfy the accelerator needs. Among the many magnets that make up a muon collider, we have identified four systems that represent well the envelope of challenges: the target and capture solenoid, the final cooling solenoid, the accelerator dipoles and the collider dipoles. These systems provide focus for the development of novel concepts, largely based on HTS for reasons of performance, cost and sustainability. After giving a consolidated overview of the needs for the magnet systems, we describe here the basic technology options considered, and the plan for design and development activities.
Quench Location in the LARP MQXFS1 Prototype Strauss, T.; Ambrosio, G.; Chlachidze, G. ...
IEEE transactions on applied superconductivity,
04/2018, Letnik:
28, Številka:
3
Journal Article
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The high luminosity upgrade project U.S. LARP/HiLumi has successfully tested the first 1.5 m prototype quadrupole MQXFS1 at Fermilab' Magnet test facility. Several thermal cycles and test programs ...were performed, with different preload configurations. To localize and characterize quenches, a quench antenna and voltage taps are used. The quench antenna was placed inside a warm bore of an anticryostat centered in the magnet. We varied the length between quench antenna segments from 2.54 to 15.24 cm, and shifted the location of the antenna to localize the quench origin along the various wedge and spacers transitions in the lead end of the magnet. We present results on the identified quench locations for the second and third thermal cycle in this paper.
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.
What is the ultimate limit to high fields in superconducting magnets for particle accelerators? In this paper we review the present status of the technology, outlining the main limitations. We first ...analyse the needed margin for operating a magnet in an accelerator. We then review the relation between current densities, coil widths, and fields in the magnets build so far. The issue of stress and the dependence on the coil lay-out is then discussed: a careful optimization between current density and coil width can be needed to keep the forces and associated strain within acceptable limits. The main issues related to cable lay-out (strand diameter, filament size) are then discussed. We conclude by giving a hint on the requirements on a HTS conductor, and a summary of Nb-Ti and Nb 3 Sn.
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). CERN and LARP are currently ...collaborating to develop a 150-mm-aperture quadrupole based on Nb3 Sn superconducting cables for the coils, and an aluminum shell with the bladder-key technology for the support structure. This paper presents the test setup for magnetic measurements, both at ambient and cryogenic temperatures, and the instrumentation being used for the first two short-models of MQXF built and tested at CERN. Finally, the measurement results, in terms of field quality, effects of persistent currents, and iron saturation are reported and discussed.
MQXF is the Nb<inline-formula><tex-math notation="LaTeX">_3</tex-math></inline-formula> Sn Low-<inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula> 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.
In this paper, we outline the present status of the design studies for the high-luminosity Large Hadron Collider, focusing on the choice of the aperture of the inner triplet quadrupoles. After ...reviewing some critical aspects of the design such as energy deposition, shielding, heat load, and protection, we present the main tentative parameters for building a 150-mm-aperture Nb 3 Sn quadrupole, based on the experience gathered by the LARP program in the past several years.
In preparation for the high-luminosity upgrade of the Large Hadron Collider (LHC), the LHC Accelerator Research Program (LARP) in collaboration with CERN is pursuing the development of MQXF: a ...150-mm-aperture high-field Nb3Sn quadrupole magnet. The development phase starts with the fabrication and test of several short models (1.2-m magnetic length) and will continue with the development of several long prototypes. All of them are mechanically supported using a shell-based support structure, which has been extensively demonstrated on several R&D models within LARP. The first short model MQXFS-AT has been assembled at LBNL with coils fabricated by LARP and CERN. In this paper, we summarize the assembly process and show how it relies strongly on experience acquired during the LARP 120-mm-aperture HQ magnet series. We present comparison between strain gauges data and finite-element model analysis. Finally, we present the implication of the MQXFS-AT experience on the design of the long prototype support structure.
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