Series Connected Hybrid for the Magnet Lab
Figure 1. Vertical Section of the Series Connected Hybrid Magnet for the Mag Lab.
The Magnet Lab has embarked on innovative projects to develop unique hybrid magnet systems. This is novel because a set of Florida-Bitter resistive coils (insert) and a set of superconducting cable-in-conduit conductor (CICC) coils (outsert) are driven in series with the same power supply, rather than independently.
In 2006, the National Science Foundation awarded the lab an $11.7 million grant for construction of a cylindrical-bore Series-Connected Hybrid (SCH), for high field nuclear magnetic resonance (NMR), condensed matter physics, biology and chemistry, to be located at the Magnet Lab’s Tallahassee location.
Figure 1 shows a vertical section of the SCH that will be housed in cell 14 of the lab’s DC Field Facility. This system will provide high magnetic field for one-third the power consumption of traditional powered magnets. The general parameters of the SCH are listed in the table below.
General Parameters of the Series Connected Hybrid Magnet
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Central Field
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36 T
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Warm Bore
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40 mm
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Operating Current
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20kA
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Uniformity Over 10 mm DSV
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1 ppm
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The SCH will allow scientific exploration into a region of high-field and high-homogeneity parameter space unavailable anywhere else in the world, as illustrated in Figure 2. At 36 T, the design field of the SCH presently exceeds the available all-superconducting fields by 62% and fields in existing all-resistive magnets with similar bore and uniformity by 44%.
Figure 2. Uniformity and central field of the series-connected hybrid magnet in relation to the 45 T and 900 MHz magnets. The region above the curve represents a regime that is presently unavailable.
Because of its naturally higher inductance/resistance ratio, this magnet configuration will have greater temporal stability than present all-resistive or hybrid magnets. Importantly, the amplitude of the high-frequency fluctuations will be preferentially suppressed, and new flux-stabilization techniques that will be developed in collaboration with researchers at Penn State University will further enhance the field stability. Homogeneity in the SCH will be improved by an order of magnitude over the world’s highest-homogeneity resistive magnet, the Magnet Lab’s 25 T Keck magnet, through the use of improved resistive magnet current grading and water-cooled resistive shims. The SCH will consume about one half the power of the existing high-uniformity, 25 T Keck magnet, resulting in lower operating costs than any magnet in its class.
Many of the technological achievements developed for our 45 T hybrid magnet will be applied to the SCH. However, the SCH will also contain several new enhancements, such as HTS leads, improved cryogenic support columns, improved superconductor, and higher strength conduit for the CICC that also has thermal properties similar to Nb3Sn.
Links
For more information, please contact Iain Dixon at dixon@magnet.fsu.edu or (850) 644-7653.
