Extensive Characterization of the 1 mm PIT &lt;formula formulatype="inline"&gt;&lt;tex Notation="TeX"&gt;${\rm Nb}_{3}{\rm Sn}$&lt;/tex&gt;&lt;/formula&gt; Strand for the 13-T FRESCA2 Magnet

Bordini, B.; Bottura, L.; Mondonico, Giorgio; Oberli, L.; Richter, David H.; Seeber, B.; Senatore, Carmine; Takala, E.; Valentinis, Davide

doi:10.1109/tasc.2011.2178217

Cited by 23 publications

(19 citation statements)

References 4 publications

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“…This justifies equation (18), suggesting that the proper quantity for scaling is the elastic energy.…”

Section: A Relation Between the Exponential Strain Function And The E...supporting

confidence: 71%

“…In this paper the new strain function is presented together with the results obtained by applying the new scaling function to a number of relevant datasets. The data analyzed consist of critical current measurements at 4.2 K that were carried out under applied axial strain at Durham University [15] and at the University of Geneva [16][17][18] on different strand types. From the critical current measured at a certain applied strain and at various magnetic fields, the B c2 (4.2 K, ε a ) was calculated using a procedure described in the paper.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An exponential scaling law for the strain dependence of the Nb₃Sn critical current density

Bordini¹,

Alknes²,

Bottura³

et al. 2013

Supercond. Sci. Technol.

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The critical current density of the Nb 3 Sn superconductor is strongly dependent on the strain applied to the material. In order to investigate this dependence, it is a common practice to measure the critical current of Nb 3 Sn strands for different values of applied axial strain. In the literature, several models have been proposed to describe these experimental data in the reversible strain region. All these models are capable of fitting the measurement results in the strain region where data are collected, but tend to predict unphysical trends outside the range of data, and especially for large strain values. In this paper we present a model of a new strain function, together with the results obtained by applying the new scaling law on relevant datasets. The data analyzed consisted of the critical current measurements at 4.2 K that were carried out under applied axial strain at Durham University and the University of Geneva on different strand types. With respect to the previous models proposed, the new scaling function does not present problems at large strain values, has a lower number of fitting parameters (only two instead of three or four), and is very stable, so that, starting from few experimental points, it can estimate quite accurately the strand behavior in a strain region where there are no data. A relationship is shown between the proposed strain function and the elastic strain energy, and an analogy is drawn with the exponential form of the McMillan equation for the critical temperature.

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“…This justifies equation (18), suggesting that the proper quantity for scaling is the elastic energy.…”

Section: A Relation Between the Exponential Strain Function And The E...supporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

An exponential scaling law for the strain dependence of the Nb₃Sn critical current density

Bordini¹,

Alknes²,

Bottura³

et al. 2013

Supercond. Sci. Technol.

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show abstract

“…Since Ũ is an increasing function of strain, this formula yields a bell-shaped curve as a function of strain, consistently with experiments. 14,16 Our model yields the functional form 1/ cosh[(B Ũ) 1/2 ] β , with B a constant, and β a number of order one. Both forms agree at small Ũ, provided A = β B/2, but the second form drops exponentially, rather than polynomially, at large Ũ.…”

Section: Introductionmentioning

confidence: 99%

A theory of the strain-dependent critical field in Nb₃Sn, based on anharmonic phonon generation

Valentinis¹,

Berthod²,

Bordini³

et al. 2013

Supercond. Sci. Technol.

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We propose a theory to explain the strain dependence of the critical properties in A15 superconductors. Starting from the strong-coupling formula for the critical temperature, and assuming that the strain sensitivity stems mostly from the electron-phonon α 2 F function, we link the strain dependence of the critical properties to a widening of α 2 F . This widening is attributed to the nonlinear generation of phonons, which takes place in the anharmonic deformation potential induced by the strain. Based on the theory of sum-and difference-frequency wave generation in nonlinear media, we obtain an explicit connection between the widening of α 2 F and the anharmonic energy. The resulting model is fit to experimental datasets for Nb 3 Sn, and the anharmonic energy extracted from the fits is compared with first-principles calculations.

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“…The average residual resistivity ratio (RRR) was measured between 84 and 125 for extracted strands. Despite this relatively low RRR, measurements on short samples have shown that the stability current in both PIT and RRP extracted strands was at least twice the operating current, which was deemed sufficient not to affect the magnet's performance (Bordini et al 2012;Oberli 2013). Cable cross-sections are shown in Fig.…”

Section: Strand and Cable Parametersmentioning

confidence: 99%

“…The critical current is measured on virgin (round) strands and strands extracted from cables using short samples (Rochepault et al 2017). Measurements have been performed at 4.3 K and the data has been fitted by parameterization curves (Bordini et al 2012) and extrapolated to 1.9 K. The degradation due to cabling, deducted from the comparison between virgin and extracted strand measurements, has been found to be on average between 2% and 5%. Figure 12.6 illustrates the estimates for the short sample limit (SSL) current I ss and peak field on the coil B peak based on the computed load lines and the critical line 16.5 17 17.5 18 18.5…”

Section: Short Sample Limits and Load Linesmentioning

confidence: 99%

CEA–CERN Block-Type Dipole Magnet for Cable Testing: FRESCA2

Rochepault

Ferracin

2019

Nb3Sn Accelerator Magnets

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The FRESCA2 dipole magnet, with a nominal field of 13 T in a 100 mm aperture, has been developed within a collaboration between the Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA) and the European Organization for Nuclear Research (CERN), in the framework of the European Coordination for Accelerator Research and Development (EuCARD) project. This chapter summarizes magnet design, technology development, fabrication, and test results. E. Rochepault (*) CEA Paris-Saclay (Commissariat à l'énergie atomique et aux énergies alternatives Paris-Saclay),

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Extensive Characterization of the 1 mm PIT <formula formulatype="inline"><tex Notation="TeX">${\rm Nb}_{3}{\rm Sn}$</tex></formula> Strand for the 13-T FRESCA2 Magnet

Cited by 23 publications

References 4 publications

An exponential scaling law for the strain dependence of the Nb₃Sn critical current density

An exponential scaling law for the strain dependence of the Nb₃Sn critical current density

A theory of the strain-dependent critical field in Nb₃Sn, based on anharmonic phonon generation

CEA–CERN Block-Type Dipole Magnet for Cable Testing: FRESCA2

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Extensive Characterization of the 1 mm PIT <formula formulatype="inline"><tex Notation="TeX">${\rm Nb}_{3}{\rm Sn}$</tex></formula> Strand for the 13-T FRESCA2 Magnet

Cited by 23 publications

References 4 publications

An exponential scaling law for the strain dependence of the Nb3Sn critical current density

An exponential scaling law for the strain dependence of the Nb3Sn critical current density

A theory of the strain-dependent critical field in Nb3Sn, based on anharmonic phonon generation

CEA–CERN Block-Type Dipole Magnet for Cable Testing: FRESCA2

Contact Info

Product

Resources

About

An exponential scaling law for the strain dependence of the Nb₃Sn critical current density

An exponential scaling law for the strain dependence of the Nb₃Sn critical current density

A theory of the strain-dependent critical field in Nb₃Sn, based on anharmonic phonon generation