Influence of high heat capacity substances doping on quench currents of fast ramped superconducting oval windings

Alekseev, P. A.; Boev, A.I.; Кейлин, В.Е.; Ковалев, И. А.; Kostrov, E. A.; Kruglov, S. L.; Lazukov, V. N.; Sadikov, I. P.; Shutova, D. I.

doi:10.1016/j.cryogenics.2005.07.005

Cited by 14 publications

(6 citation statements)

References 4 publications

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“…To further improve thermal stability and training in accelerator magnets, the idea of increasing superconductor's stability, usually based on its minimum quench energy (MQE), by inserting high specific heat (high-C p ) elements in SC wires dates back to the 1960s [5]. Then in the mid-2000s, a considerable improvement in stability to pulsed disturbances was obtained for NbTi windings, when distributing large heat capacity substances on the conductor during winding [6,7]. The MQEs of the brushed coils were several times higher, and thermal efficiency was greatest for temperature diffusion times much smaller than the disturbance pulse duration.…”

Section: Introductionmentioning

confidence: 99%

A new ductile, tougher resin for impregnation of superconducting magnets

Barzi,

Turrioni,

Kesgin

et al. 2024

Supercond. Sci. Technol.

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A major remaining challenge for Nb3Sn high field magnets is their training due to random temperature variations in the coils. The main objective of our research is to reduce or eliminate it by finding novel impregnation materials in replacement of the epoxies currently used. An organic olefin-based thermosetting dicyclopentadiene (DCP) resin, C10H12, commercially available in Japan as TELENE® by RIMTEC, was used to impregnate a short Nb3Sn undulator coil developed by ANL and FNAL. This magnet reached short sample limit after only two quenches, compared with ~100 when CTD-101K® was used. Ductility, i.e. the ability to accept large strains, and toughness were identified as key properties to achieve these results. In addition, we have been investigating whether mixing TELENE with high heat capacity ceramic powders such as Gd2O3, Gd2O2S, and HoCu2, increases the specific heat (Cp) of impregnated Nb3Sn superconducting magnets. The viscosity, heat capacity, thermal conductivity, and other physical properties of TELENE with high-Cp powder fillers were measured in this study as a function of temperature and magnetic field. The TELENE-87wt%Gd2O2S had a peak in Cp between 4.3 K and 5.3 K at fields between 0 and 8 T. We have also investigated the effect on the mechanical properties of pure and mixed TELENE under 10 Gy of gamma ray irradiation at the Takasaki Advanced Radiation Research Institute in Takasaki, Japan. TELENE-87wt%Gd2O2S exhibited exceptional radiation resistance. Impregnating an undulator coil with TELENE mixed with Gd2O2S powder will verify whether the coils’ thermal stability further improves, or whether its low diffusivity will require engineering the material with high-thermal conductivity components. Short magnet training will lead to better magnet reliability, lower magnet margins, lower risk and substantial saving in accelerators’ commissioning costs. 

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Section: Introductionmentioning

confidence: 99%

A new ductile, tougher resin for impregnation of superconducting magnets

Barzi,

Turrioni,

Kesgin

et al. 2024

Supercond. Sci. Technol.

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show abstract

“…The idea to increase the MQE by inserting high specific heat (high-C p ) elements in superconducting wires dates to 1960 [7]. In the mid-2000s, a considerable improvement in stability to pulsed disturbances was obtained for NbTi windings, when distributing large heat capacity substances on the conductor during winding [8,9]. The windings were brushed with CeCu 6 and HoCu 2 in the form of powders with 50-70 µm grain size and a volumetric content of 3 to 6%.…”

Section: Introductionmentioning

confidence: 99%

Heat Diffusion in High-Cp Nb3Sn Composite Superconducting Wires

et al. 2020

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A major focus of Nb3Sn accelerator magnets is on significantly reducing or eliminating their training. Demonstration of an approach to increase the Cp of Nb3Sn magnets using new materials and technologies is very important both for particle accelerators and light sources. It would improve thermal stability and lead to much shorter magnet training, with substantial savings in machines’ commissioning costs. Both Hypertech and Bruker-OST have attempted to introduce high-Cp elements in their wire design. This paper includes a description of these advanced wires, the finite element model of their heat diffusion properties as compared with the standard wires, and whenever available, a comparison between the minimum quench energy (MQE) calculated by the model and actual MQE measurements on wires.

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“…The specific heat of superconductors (such as NbTi and Nb 3 Sn) and matrix (Cu) can hardly be significantly increased; however, there is a class of materials with high specific heat at low temperatures, and the addition of such substances to a superconducting wire in a proper architecture can improve its overall C [5][6][7]. Experiments have shown that the high specific heat of these substances was not fully utilized when they were added to epoxy, which has low thermal diffusivity [8]; however, when they were directly added into superconducting wires (e.g., being placed between the Ta barrier and the outside Cu sheath in bronze-process Nb 3 Sn wires [9], or being filled into holes that were drilled in the Cu matrix in NbTi billets [10]), the minimum quench energies (MQE) of these conductors were significantly increased (e.g., by factors of five to seven as reported in [9]). Nevertheless, these schemes of adding high-C substances significantly increased billet fabrication difficulty and undermined wire drawability, making it difficult to obtain practical long-length wires.…”

Section: Introductionmentioning

confidence: 99%

Improvement of stability of Nb₃Sn superconductors by introducing high specific heat substances

Zlobin

et al. 2018

Supercond. Sci. Technol.

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High-J c Nb 3 Sn conductors have low stability against perturbations, which accounts for the slow training rates of high-field Nb 3 Sn magnets. While it is known that adding substances with high specific heat (C) into Nb 3 Sn wires can increase their overall specific heat and thus improve their stability, there has not been a practical method that is compatible with the fabrication of longlength conductors. In this work, we put forward a scheme to introduce such substances to distributed-barrier Nb 3 Sn wires, which adds minimum difficulty to the wire manufacturing process. Multifilamentary wires using a mixture of Cu and high-C Gd 2 O 3 powders have been successfully fabricated along this line. Measurements showed that addition of Gd 2 O 3 had no negative effects on residual resitivity ratio or non-Cu J c , and that flux jumps were remarkably reduced, and minimum quench energy values at 4.2 K, 14 T were increased by a factor of three, indicating that stability was significantly improved. We also discussed the influences of the positioning of high-C substances and their thermal diffusivity on their effectiveness in reducing the superconductor temperature rise against perturbations. Based on these results, we proposed an optimized conductor architecture to maximize the effectiveness of this approach.

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Influence of high heat capacity substances doping on quench currents of fast ramped superconducting oval windings

Cited by 14 publications

References 4 publications

A new ductile, tougher resin for impregnation of superconducting magnets

A new ductile, tougher resin for impregnation of superconducting magnets

Heat Diffusion in High-Cp Nb3Sn Composite Superconducting Wires

Improvement of stability of Nb₃Sn superconductors by introducing high specific heat substances

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Influence of high heat capacity substances doping on quench currents of fast ramped superconducting oval windings

Cited by 14 publications

References 4 publications

A new ductile, tougher resin for impregnation of superconducting magnets

A new ductile, tougher resin for impregnation of superconducting magnets

Heat Diffusion in High-Cp Nb3Sn Composite Superconducting Wires

Improvement of stability of Nb3Sn superconductors by introducing high specific heat substances

Contact Info

Product

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Improvement of stability of Nb₃Sn superconductors by introducing high specific heat substances