Low field flux jumping in high performance multifilamentary Nb/sub 3/Al and Nb/sub 3/Sn composite strands

Sumption, M.D.; Collings, E. W.; Gregory, E.

doi:10.1109/77.784666

Cited by 11 publications

(5 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first column shows the amplitude of the hysteresis loop ΔM at 3 T and 1.9 K for each sample; this value was chosen as parameter to quantify the magnetization of the sample in the field region where flux jumps do not take place. The next columns present the 4 and 5, one can notice that the maximum flux jump amplitude at 1.9 K is correlated to the magnetization of the sample: the larger the magnetization the larger the flux jump amplitude. This relationship is particularly clear when plotting the magnetization of each sample just before it experiences the largest flux jump and the amplitude of this flux jump (Fig.…”

Section: A Flux Jumps Analysismentioning

confidence: 98%

“…The high J c, which is more than two times larger than the one of ITER type wires, is obtained at the expense of a large effective filament size D eff of the superconductor. In these wires each sub-element acts as a single filament: in Powder In Tube (PIT) wires the sub-element is constituted of a Nb tube filled with Nb-Sn powder, and during the reaction the tin diffuses transforming the Nb tube into a Nb 3 and the large D eff cause a huge magnetization within the conductor that might compromise the magnet field quality [4]- [8]. Indeed such a large magnetization not only implies a specific design of the magnets to compensate for the field contribution of the persistent currents, but also generates fluxjumps [4]- [8].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetization Measurements of High-$J_{\rm c}$$\hbox{Nb}_{3}\hbox{Sn}$ Strands

Bordini

Richter

Alknes

et al. 2013

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

High critical current density Nb 3 Sn wires (J c > 2500 A/mm 2 at 4.2 K and 12 T) are the conductors considered for next generation accelerator magnets. At present, the large magnetization of these strands is a concern within the scientific community because of the impact it might have on the magnet field quality. In order to characterize the magnetic behavior of these wires, an extensive campaign of magnetization measurements was launched at CERN. Powder In Tube (PIT) strands by Bruker-EAS and Restacked Rod Process (RRP ® ) strands by Oxford Superconducting Technology (OST) were measured between 0 T and 10.5 T at different temperatures (ranging from 1.9 K to 14.5 K). The samples, based on strands with different subelements dimensions (35 to 80 μm), were measured with a Vibrating Sample Magnetometer (VSM). The experimental data were analyzed to: 1) calculate the effective filament size and the optimal parameters for the pinning force scaling law; 2) define the field-temperature region where there are flux jumps. It was found that the flux-jump can limit the maximum magnetization of the Nb 3 Sn wires and that the maximum magnetization at higher temperatures can be larger than the one at lower temperatures. In this paper the experimental results and the analysis are reported and discussed. The experimental data were analyzed to: 1) calculate the effective filament size and the optimal parameters for the pinning force scaling law; 2) define the field-temperature region where there are flux jumps. It was found that the flux-jump can limit the maximum magnetization of the Nb 3 Sn wires and that the maximum magnetization at higher temperatures can be larger than the one at lower temperatures. In this paper the experimental results and the analysis are reported and discussed.

show abstract

Section: A Flux Jumps Analysismentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Magnetization Measurements of High-$J_{\rm c}$$\hbox{Nb}_{3}\hbox{Sn}$ Strands

Bordini

Richter

Alknes

et al. 2013

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

show abstract

“…5,6 Moreover, there are still open questions related to flux jumping in general, namely, that samples often appear more stable experimentally than predicted by theories. 1 In investigations of such avalanche events, one can benefit significantly by using thin-film samples, where one can visualize the development of the instability by monitoring spatial distributions of the magnetic flux.…”

Section: -3mentioning

confidence: 99%

Dendritic flux avalanches in superconducting Nb3Sn films

et al. 2003

View full text Add to dashboard Cite

The penetration of magnetic flux into a thin superconducting film of Nb3Sn with critical temperature 17.8K and critical current density 6MA/cm^2 was visualized using magneto-optical imaging. Below 8 K an avalanche-like flux penetration in form of big and branching dendritic structures was observed in response to increasing perpendicular applied field. When a growing dendritic branch meets a linear defect in the film, several scenarios were observed: the branch can turn and propagate along the defect, continue propagation right through it, or "tunnel" along a flux-filled defect and continue growth from its other end. The avalanches manifest themselves in numerous small and random jumps found in the magnetization curve.Comment: 3 pages, 4 figures, submitted to Cryogenics. Revision: M(H) data adde

show abstract

“…Large flux jumps can even cause magnet quenching. The flux jump behavior of Nb 3 Sn strands in the absence of transport current has been intensively studied [8][9][10][11][12]. Early works by Swartz [8] and Wilson [9] led to criteria for magnetization flux jumps in the adiabatic limit.…”

Section: Introductionmentioning

confidence: 99%

“…Early works by Swartz [8] and Wilson [9] led to criteria for magnetization flux jumps in the adiabatic limit. Sumption et al [10][11][12] early on measured the properties and described the characteristics of the low-field flux jump regime of the new high performance, large d eff Nb 3 Sn conductors for high energy physics applications.…”

Section: Introductionmentioning

confidence: 99%

Influence of heat treatment temperature and Ti doping on low-field flux jumping and stability in (Nb-Ta)₃Sn strands

Sumption

Collings

2014

Supercond. Sci. Technol.

View full text Add to dashboard Cite

The impacts of heat treatment (HT) temperature and Ti doping on low-field flux jumping and 12 T J c of high-performance internal-Sn, distributed barrier (Nb-Ta) 3 Sn strands have been explored. It was found that higher HT temperatures could suppress low-field flux jumps by not only reducing the J c (B) curve slope, but also increasing the heat capacity and decreasing the dJ c / dT. A metric, J c,3 T /J c,12 T (the ratio of 3 T to 12 T J c ), was used to describe the slope of the J c (B) curve. In addition, an analytical equation was derived to predict the amplitude of a flux jump. The J c (B) curves were further analyzed in the form of Kramer plots to extract the irreversibility field, B irr , and the maximum bulk pinning forces, F p,max . The variations of B irr , F p,max and grain size, d, with HT and Ti doping were also analyzed. F p,max initially increasing linearly with 1/d, saturated at small values of d, possibly because the grains became columnar.

show abstract

Low field flux jumping in high performance multifilamentary Nb/sub 3/Al and Nb/sub 3/Sn composite strands

Cited by 11 publications

References 18 publications

Magnetization Measurements of High-$J_{\rm c}$$\hbox{Nb}_{3}\hbox{Sn}$ Strands

Magnetization Measurements of High-$J_{\rm c}$$\hbox{Nb}_{3}\hbox{Sn}$ Strands

Dendritic flux avalanches in superconducting Nb3Sn films

Influence of heat treatment temperature and Ti doping on low-field flux jumping and stability in (Nb-Ta)₃Sn strands

Contact Info

Product

Resources

About

Low field flux jumping in high performance multifilamentary Nb/sub 3/Al and Nb/sub 3/Sn composite strands

Cited by 11 publications

References 18 publications

Magnetization Measurements of High-$J_{\rm c}$$\hbox{Nb}_{3}\hbox{Sn}$ Strands

Magnetization Measurements of High-$J_{\rm c}$$\hbox{Nb}_{3}\hbox{Sn}$ Strands

Dendritic flux avalanches in superconducting Nb3Sn films

Influence of heat treatment temperature and Ti doping on low-field flux jumping and stability in (Nb-Ta)3Sn strands

Contact Info

Product

Resources

About

Influence of heat treatment temperature and Ti doping on low-field flux jumping and stability in (Nb-Ta)₃Sn strands