Quench protection challenges in long nb3sn accelerator magnets

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The US-LARP collaboration is developing a new generation of large-aperture high-field quadrupoles based on Nb Sn superconductor for the LHC upgrades. The development and implementation of this new technology involves the fabrication and testing of series of model magnets, coils and other components with various design and processing features. New 120-mm HQ coils made of Rutherford cable, one with an interlayer resistive core, and both with optimized reaction processes, were fabricated and tested using a quadrupole mirror structure under operating conditions similar to those in a real magnet. The coils were instrumented with voltage taps and strain gauges to study the mechanical and quench performance. Quench antenna and temperature gauges were installed in the mirror structure to measure the coil temperature and locate quench origins. This paper presents details of the coil design and fabrication procedures, coil assembly and pre-stress in the quadrupole mirror structure, and coil test results.Index Terms-LARP, magnet test, magnetic mirror, quadrupole coil.

“…Results of this study are reported in [13]. The residual resistivity ratio (RRR) of HQ12 coil was measured during magnet warm up, with values varying from 260 to 320.…”

Section: A Quench Historymentioning

confidence: 99%

Optimization and Test of 120 mm LARP Nb$_{3}$Sn Quadrupole Coils Using Magnetic Mirror Structure

Bossert

Ambrosio

Andreev

et al. 2012

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“…The phenomenon of quench, characterized by the sudden loss of superconductivity in a magnet's conductor, is a critical safety consideration in the design and operation of the magnets. Early quench detection and a prompt protection system response is essential to limit the local temperature increase and to avoid conductor damage [2]. After quench detection, the magnet energy must be discharged quickly.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Simulation of Quench Propagation in Nb₃Sn Cables Covered With Protection Heaters

Balani,

Salmi,

Calvelli

et al. 2024

Superconducting magnets are crucial components in various scientific, industrial, and medical applications, offering unparalleled high magnetic fields and energy efficiency. However, the transition from the superconducting to the normal state, known as a quench, can pose significant challenges due to the sudden local release of stored energy and damage to the magnet system. Quench protection strategies have emerged as essential mechanisms to mitigate the adverse effects of quenches. One of the commonly used methods in accelerator magnets is to use strip heaters on coil surfaces. The heater element length and configuration influence the performance of the quench protection. The study of the quench protection by heaters requires the coupled modelling of the Joule heating, normal zone propagation, and transferring heat from the heaters to the cable. In this paper, we present a new 2D finite element simulation model to model the increase of the cable resistance under different heater lengths in Nb3Sn accelerator magnets. The model allows analyzing heaters with several different lengths of heating stations along the cable. This strategy can be used to maximize the cable resistance increase at high operation current while still providing the needed normal zone propagation at lower currents. We demonstrate the model use with a high-field racetrack dipole model.

“…2) to manage the stress of 150 MPa due to Lorentz force is given by an aluminum cylinder and loaded with bladders and keys, allowing precise stress control [9]. One of the main challenges of this magnet is the protection [10,11,12]: the time margin available to the protection system to quench the magnet is of the order of 40 ms (it is 100 ms in the LHC dipoles), i.e. just at the limit of present electronics and quench heaters.…”

Section: Triplet Qxfmentioning

confidence: 99%

A First Baseline for the Magnets in the High Luminosity LHC Insertion Regions

Todesco

Allain

Ambrosio

et al. 2014

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127

In this paper we give a first baseline of the interaction region. We discuss the main motivations that lead us to choose the technology, the combination of fields/gradients and lengths, the apertures, the quantity of superconductor, and the operational margin. Key elements are also the constraints given by the energy deposition in terms of heat load and radiation damage; we present the main features related to shielding and heat removal.