Technology of 1 GHz NMR superconducting magnets

Markiewicz, W.D.; Bonney, L.A.; Dixon, I.R.; Eyssa, Y.M.; Swenson, Charles A.; Schrieider-Muntau, H.J.

doi:10.1016/0921-4526(95)00471-8

Cited by 10 publications

(5 citation statements)

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“…The first of the two systems considered here is a hypothetical modification of the 900 MHz/21.1 T NMR magnet referred to as 'Modified900'. The original magnet design included an option to modify the inner sections to upgrade to a 25 T magnet [2]. Sections 4-11 as listed in figure 1 correspond to all but the inner section of the original design and form a 20 T outsert.…”

Section: Examples Of 25 T Magnet Designs With Bscco Insertmentioning

confidence: 99%

“…Research magnets find application as general-purpose facilities for solid-state physics research or specialized research as, for example, in high-B/T facilities. In both classes there is a strong desire to push the existing technology to higher magnetic fields [1,2]. Currently the limit of existing magnets, based on NbTi and Nb 3 Sn, is around 21 T. A target of 23.5 T for 1 GHz NMR is actively pursued among research institutions [1] and in industry, considering mostly Nb 3 Sn, Nb 3 Al, YBa 2 Cu 3 O x and BSCCO conductors.…”

Section: Introductionmentioning

confidence: 99%

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Effects of conductor anisotropy on the design of Bi Sr Ca Cu O sections of 25 T solenoids

Weijers¹,

Schwartz²,

Haken³

et al. 2003

Supercond. Sci. Technol.

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The development of a 25 T superconducting magnet is usually envisioned with the use of an innermost coil wound with high-temperature superconductor (HTS) material. At present, Bi2Sr2CaCu2Ox and Bi2Sr2Ca2Cu3Ox (BSCCO) conductors are the only candidate conductors available with sufficient length and current carrying capability. Unlike NbTi and Nb3Sn conductors, the BSCCO crystal structure and thus properties are strongly anisotropic. In conductor form, various degrees of anisotropy occur. It is often assumed that this anisotropy simply implies that radial field components must be minimized. We show that this assumption can be misleading. Using the average grain colony misalignment angle to parameterize the anisotropy, three regimes are distinguished in the relationship between average grain colony misalignment and critical current limiting field components. The implications of these separate regimes on the design process for 25 T superconducting magnet design are discussed.

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Section: Examples Of 25 T Magnet Designs With Bscco Insertmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of conductor anisotropy on the design of Bi Sr Ca Cu O sections of 25 T solenoids

Weijers¹,

Schwartz²,

Haken³

et al. 2003

Supercond. Sci. Technol.

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show abstract

“…The relevant applied magnetic field conditions for the conductor are up to 25 T in parallel orientation and in the order of 2-3 T in perpendicular orientation. The latter number varies with the degree of anisotropy of the conductor and design of the 30 The relation between current density and compactness is addressed in section 1-3. magnet 31 . Regardless of the exact value of the applicable perpendicular magnetic field, it is clear that conductors B, C and E perform around the J e = 200 A/mm 2 target while conductors A and F exceed this value.…”

Section: ____________________________________________________________mentioning

confidence: 99%

“…So one arrives at a convenient rule-of-thumb that a typical coil generates about 1 tesla per centimeter winding thickness if the average winding current density is 100 A/mm 2 . This current density value is used as the benchmark value for HTS insert coils at the NHMFL [30] 10 . Accordingly a total winding thickness of about 5 cm is foreseen for an HTS insert generating 5 T.…”

Section: Irmentioning

confidence: 99%

“…Conductors E and F do not show a double-step behavior in the range from self-field to 45 T applied magnetic field, as shown in Figure 3 To establish the relevance of the conductors, a comparison between their current density and generic requirements for their use in 25 T magnets is in order. Average current densities in the winding of around 100 A/mm 2 lead to reasonably compact magnets designs 30 . Taking a ratio between average current density and engineering critical current density of 0.5 to 0.7 to be typical leads to a minimum desirable engineering critical current density in the range of 140-200 A/mm 2 .…”

Section: ____________________________________________________________mentioning

confidence: 99%

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High-temperature superconductors in high-field magnets

Weijers

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Preface and acknowledgementThis thesis deals with selected topics out of a wide research and development effort on HTS insert coil technology. Its origin goes back to the founding charter of the NHMFL in the year 1988 which listed the goal of realizing a 25 T superconducting magnet as one of the milestones the NHMFL was to achieve. High-temperature superconductors had only just been discovered and the required technology was non-existent. The path to where we are now has been eventful and a real learning experience. From the early days in the mid-1990-ies of the 'Wind and Pray" approach when coil testing relentlessly pointed out the shortcomings of both conductor and coil technologies at the time to the first successful "mini-coils" (around coil number 70) to the successive 1 T, 3 T and 5 T inserts (the latter reaching 25 T and bringing the total of numbered coils over 300 a decade later) to the promise of 30 + T superconducting user magnets with coated conductors in the not-toodistant future.Lacking the funds to buy the very expensive conductors, a collaboration was established with industry. This approach has served us well and resulted in a wide assortment of conductors to work with. New superconductors were donated in exchange for feedback on its performance as observed in our magnet technology development program. We also tested complete coils built by ourselves or by partners, in background magnetic field, a task for which the NHMFL facilities are well suited.This work is centered on the 5T insert coil for a total magnetic field of 25 T, but the research and development effort is interwoven with and inseparable from the broader HTS insert coil technology development program. Therefore discussions on a wider range of conductors and coils in line with the broader scope of this thesis are presented.While I take full responsibility for the described NHMFL insert coil designs, analysis and interpretation of the data on coils and conductors, having executed or been directly involved with all experiments described and having wound many a coil, this work has had the benefit of many direct and indirect contributions of a large number of people inside and outside the NHMFL. In contrast, developing this thesis itself has been the loneliest work I have ever done, but ultimately just as rewarding. There are many people that I would like to thank for their contributions to the HTS insert program in general and this thesis in particular.

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Practical Application of High Temperature Superconductors

Watanabe

Motokawa

2002

Materials Science in Static High Magnetic Fields

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Technology of 1 GHz NMR superconducting magnets

Cited by 10 publications

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Effects of conductor anisotropy on the design of Bi Sr Ca Cu O sections of 25 T solenoids

Effects of conductor anisotropy on the design of Bi Sr Ca Cu O sections of 25 T solenoids

High-temperature superconductors in high-field magnets

Practical Application of High Temperature Superconductors

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