Low temperature superconductor and aligned high temperature superconductor magnetic dipole system and method for producing high magnetic fields
09793036 · 2017-10-17
Assignee
Inventors
- Ramesh Gupta (Shoreham, NY, US)
- Ronald Scanlan (Ramona, CA, US)
- Arup K. Ghosh (Shoreham, NY, US)
- Robert J. Weggel (Reading, MA, US)
- Robert Palmer (Shoreham, NY, US)
- Michael D. Anerella (Jamaica Estates, NY, US)
- Jesse Schmalzle (Shoreham, NY, US)
Cpc classification
International classification
Abstract
A dipole-magnet system and method for producing high-magnetic-fields, including an open-region located in a radially-central-region to allow particle-beam transport and other uses, low-temperature-superconducting-coils comprised of low-temperature-superconducting-wire located in radially-outward-regions to generate high magnetic-fields, high-temperature-superconducting-coils comprised of high-temperature-superconducting-tape located in radially-inward-regions to generate even higher magnetic-fields and to reduce erroneous fields, support-structures to support the coils against large Lorentz-forces, a liquid-helium-system to cool the coils, and electrical-contacts to allow electric-current into and out of the coils. The high-temperature-superconducting-tape may be comprised of bismuth-strontium-calcium-copper-oxide or rare-earth-metal, barium-copper-oxide (ReBCO) where the rare-earth-metal may be yttrium, samarium, neodymium, or gadolinium. Advantageously, alignment of the large-dimension of the rectangular-cross-section or curved-cross-section of the high-temperature-superconducting-tape with the high-magnetic-field minimizes unwanted erroneous magnetic fields. Alignment may be accomplished by proper positioning, tilting the high-temperature-superconducting-coils, forming the high-temperature-superconducting-coils into a curved-cross-section, placing nonconducting wedge-shaped-material between windings, placing nonconducting curved-and-wedge-shaped-material between windings, or by a combination of these techniques.
Claims
1. A high-magnetic-field dipole-magnet system comprising: a plurality of high-temperature-superconducting-coils comprised of windings of high-temperature-superconducting-tape with the width of said high-temperature-superconducting-tape substantially aligned with said high-magnetic-field; a plurality of low-temperature-superconducting-coils comprised of windings of low-temperature-superconducting-wire; a cooling system to cool said high-temperature-superconducting-coils and to cool said low-temperature-superconducting-coils; a first plurality of support-structures located proximate to said high-temperature-superconducting-coils to support said high-temperature-superconducting-coils; a second plurality of support-structures located proximate to said low-temperature-superconducting-coils to support said low-temperature-superconducting-coils; a first plurality of electrical-contacts located at the ends of said high-temperature-superconducting-coils to allow electric-current into and out of said high-temperature-superconducting-coils; a second plurality of electrical-contacts located at the ends of said low-temperature-superconducting-coils to allow electric-current into and out of said low-temperature-superconducting-coils; and an open-region located in the radially-central-region of said dipole-magnet system.
2. The system in accordance with claim 1, wherein said high-temperature-superconducting-coils are located in radially-inward-regions of said dipole-magnet.
3. The system in accordance with claim 1, wherein said low-temperature-superconducting-coils are located in radially-outward-regions of said dipole-magnet.
4. The system in accordance with claim 1, wherein said high-temperature-superconducting-coils are comprised of bismuth-strontium-calcium-copper-oxide.
5. The system in accordance with claim 1, wherein said high-temperature-superconducting-coils are comprised of rare-earth-metal, barium-copper-oxide (ReBCO) compounds, wherein said rare-earth-metal is yttrium, samarium, neodymium, or gadolinium or combinations thereof.
6. The system in accordance with claim 1, wherein said high-temperature-superconducting-tape has a rectangular-cross-section positioned and aligned so that a large-dimension of said rectangular-cross-section is substantially parallel to said high-magnetic-field.
7. The system in accordance with claim 1, wherein said high-temperature-superconducting-tape has a curved-cross-section comprised of curved-segments separated by a distance positioned and aligned so that said curved-segments of said curved-cross-section are substantially parallel to said high-magnetic-field.
8. The system in accordance with claim 1, wherein said high-temperature-superconducting-coils are comprised of windings of said high-temperature-superconducting-tape that have a rectangular-cross-section and are positioned and aligned by a nonconducting wedge-shaped-material between said windings of said high-temperature-superconducting-coils so that a large-dimension of said rectangular-cross-section is substantially parallel to said high-magnetic-field.
9. The system in accordance with claim 1, wherein said high-temperature-superconducting-coils are comprised of windings of said high-temperature-superconducting-tape that have a combination of a rectangular-cross-section and a curved-cross-section, and are positioned and aligned by a nonconducting curved-and-wedge-shaped-material between said windings of said high-temperature-superconducting-coils so that a large-dimension of said rectangular-cross-section and said curved-cross-section is substantially parallel to said high-magnetic-field.
10. A method of producing high-magnetic-fields in a dipole-magnet comprising the steps of: operating a plurality of high-temperature-superconducting-coils comprised of windings of high-temperature-superconducting-tape with a width of said high-temperature-superconducting-tape substantially aligned with said high-magnetic-field; operating a plurality of low-temperature-superconducting-coils comprised of windings of low-temperature-superconducting-wire; operating a cooling system to cool said high-temperature-superconducting-coils and to cool said low-temperature-superconducting-coils; operating a first plurality of support-structures located proximate to said high-temperature-superconducting-coils to support said high-temperature-superconducting-coils against large Lorentz-forces present in said dipole-magnet; operating a second plurality of support-structures located proximate to said low-temperature-superconducting-coils to support said low-temperature-superconducting-coils against large Lorentz-forces present in said dipole-magnet; operating a first plurality of electrical-contacts located at ends of said high-temperature-superconducting-coils to allow electric-current into and out of said high-temperature-superconducting-coils; operating a second plurality of electrical-contacts located at ends of said low-temperature-superconducting-coils to allow electric-current into and out of said low-temperature-superconducting-coils; operating an open-region located in a radially-central-region of said dipole-magnet.
11. The method in accordance with claim 10, wherein said high-temperature-superconducting-coils are located in radially-inward-regions of said dipole-magnet.
12. The method in accordance with claim 10, wherein said low-temperature-superconducting-coils are located in radially-outward-regions of said dipole-magnet.
13. The method in accordance with claim 10, wherein said high-temperature-superconducting-coils are comprised of bismuth-strontium-calcium-copper-oxide.
14. The method in accordance with claim 10, wherein said high-temperature-superconducting-coils are comprised of rare-earth-metal, barium-copper-oxide (ReBCO) compounds, wherein said rare-earth-metal is yttrium, samarium, neodymium, or gadolinium or combinations thereof.
15. The method in accordance with claim 10, wherein said high-temperature-superconducting-tape has a rectangular-cross-section positioned and aligned so that a large-dimension of said rectangular-cross-section is substantially parallel to said high-magnetic-field.
16. The method in accordance with claim 10, wherein said high-temperature-superconducting-tape has a curved-cross-section comprised of curved-segments separated by a distance positioned and aligned so that said curved-segments of said curved-cross-section are substantially parallel to said high-magnetic-field.
17. The method in accordance with claim 10, wherein said high-temperature-superconducting-coils are comprised of windings of said high-temperature-superconducting-tape that have a rectangular-cross-section and are positioned and aligned by nonconducting wedge-shaped-material between said windings of said high-temperature-superconducting-coils so that a large-dimension of said rectangular-cross-section is substantially parallel to said high-magnetic-field.
18. The method in accordance with claim 10, wherein said high-temperature-superconducting-coils are comprised of windings of said high-temperature-superconducting-tape that have a combination of a rectangular-cross-section and a curved-cross-section, and are positioned and aligned by nonconducting curved-and-wedge-shaped-material between said windings of said high-temperature-superconducting-coils so that a large-dimension of said rectangular-cross-section and said curved-cross-section is substantially parallel to said high-magnetic-field.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention is explained in more detail below with reference to the accompanying drawings in which:
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DETAILED DESCRIPTION
(18) In the following detailed description of the embodiments, reference is made to the accompanying drawings, which form a part hereof. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
(19) In the present disclosure, a high-magnetic-field dipole-magnet system and methods are described to achieve high-magnetic-fields in a dipole-magnet 16 which may be in the range of 16-25 or 19-25 teslas by using a combination of Low Temperature Superconductors (LTS) and High Temperature Superconductors (HTS). Superconducting magnets include a liquid-helium-system to cool superconducting materials to the temperatures needed to support a high current density in the high-magnetic-field, support-structures to support the superconductors against the large Lorentz-forces present in the system, electrical-contacts to bring electric-current into and out of the superconductors, and an open-region located in a radially-central-region to allow particle beam transport and other uses, and the present system will include these aspects as well.
(20) HTS manufacturing techniques produce the HTS material in a tape form. Tapes are geometries that have a very small thickness, a larger width, and an even larger length.
(21) Reducing Persistent-Current Effects.
(22) In the present disclosure, a system and methods are described for a high-magnetic-field dipole-magnet 16 designed to have magnetic-field-lines 18 that may be substantially aligned with the HTS-tape-width 6 to reduce the persistent-current effects. (As is customary, this disclosure defines magnetic-field-lines 18 as lines that are aligned with the direction of the vector high-magnetic-field.) The present system design is based on the principle that persistent-currents may be determined primarily by the width of the conductor perpendicular to the magnetic-field-lines 18. The HTS-coil 12 designs may be made where the magnetic-field-lines 18 are oriented or aligned in such a way that they are substantially parallel to the HTS-tape-width 6 and substantially perpendicular to the HTS-tape-thickness 4. Since the conductor thickness within the HTS-tape 2 may be in the range of 0.5 microns to 3 microns, it is several orders of magnitude smaller than the HTS-tape-width 6, hence proper alignment may reduce the persistent-current effects by several orders of magnitude.
(23) The present method may be used in a hybrid design for dipole-magnet 16, quadrupole or higher multi-pole magnets. It is a challenge to align the magnetic-field-lines 18 at all points in a magnet. However, in hybrid magnet designs, HTS-coils 12 are used in the higher field, radially-inward-regions where it is possible to align the magnetic-field-lines 18 within one degree to five degrees of the HTS-tape-width 6. Low-temperature-superconducting-coils (LTS-coils) (comprised of materials such as Nb3Sn and/or NbTi), which are composed of fine filaments of low-temperature-superconducting-wire, have much smaller magnetization than the HTS-tape 2 conductors and do not create similarly large field distortions. Hence, LTS-coils can be used in the lower field, radially-outward-regions. An example of a field plot is found in
(24) Reducing Field Errors.
(25) The magnet design may be developed where the HTS-coils 12 are oriented to align the HTS-tape-width 6 parallel to the magnetic-field-lines 18 to reduce the field errors caused by magnetization.
(26) The present magnet design may reduce the magnetization-induced field distortions in magnets made with HTS-tape 2. The present design is based on the principle that field harmonics from induced persistent-currents may be determined primarily by the width of the conductor perpendicular to the magnetic-field-lines 18. The magnet designs are based on including as much as possible of the narrower side of the HTS-tape 2 and aligning it perpendicularly to the magnetic-field-lines 18 to reduce by an order to several orders of magnitude the field errors caused by persistent-currents. This design may increase the technical and economic viability of HTS-tape 2 use in future applications.
(27) The magnitude of persistent-current magnetization that may cause unwanted distortion is related to the dimension of the tape that is perpendicular to the field. To reduce the persistent-current effects the HTS-coil 12 designs may be made where the magnetic-field-lines 18 are oriented or aligned in such a way that they are substantially parallel to the HTS-tape-width 6 and substantially perpendicular to the HTS-tape-thickness 4. Since the HTS-tape-thickness 4 is several orders of magnitude smaller than the HTS-tape-width 6, the persistent-current effects may be reduced by several orders of magnitude in comparison with a conventional magnet design.
(28) Reducing Conductor Magnetization and its Degradation of Field Homogeneity; Increasing Efficiency.
(29) The present method uses the alignment of the HTS-tape 2 with the magnetic-field-lines 18 to reduce conductor magnetization and its degradation of field homogeneity. This orientation or alignment also may contribute to increasing the efficiency of the HTS-tape 2 in the magnet.
(30) The conductor magnetization effects in HTS magnets may be reduced by substantially aligning the HTS-tape-width 6 with the magnetic-field-lines 18. HTS-tape 2 conductors have one wide dimension with a width typically of 4 mm to 12 mm, with large width for higher current, and a thickness typically of 0.5 microns to 3 microns of superconductor. Thus, if the HTS-tape-width 6 is aligned substantially parallel to the magnetic-field-lines 18, the persistent-current effect may be reduced by orders of magnitude as compared to those in the conventional designs. With the present disclosure employing a substantially aligned tape design across the width, the effective filament size determining magnetization effects may be only 0.5 microns to 3 microns.
(31) It has been found that in hybrid magnet designs where HTS-coils 12 are used in the higher field regions and conventional LTS-coils are used in the lower field regions, it is possible to align the HTS-tape-width 6 within 1 degree to 5 degrees of the magnetic-field-lines 18. LTS-coils (typically of Nb.sub.3Sn and/or NbTi strands with hundreds to millions of very fine filaments) have much smaller magnetization than HTS-tape 2 conductors and therefore may not create similarly large field distortions. This technique is illustrated for an open midplane dipole design in the first figure found in R. Gupta, “HTS Open Midplane Dipole,” 2008 Low Temperature Superconductor Workshop, Tallahassee, Fla., Nov. 11-13, 2008 http://www.bnl.gov/magnets/Staff/Gupta/Talks/ltsw08/ltsw08-omd-gupta.pdf) incorporated herein by reference in its entirety.
(32) The HTS-coils 12 (
An Embodiment—Tilting the Coils
(33) An embodiment could involve tilting/angling the HTS-coils 12 to substantially align them with the magnetic-field-lines 18.
(34) The HTS-coils 12 may be tilted to align them substantially parallel to the magnetic-field-lines 18 as much as possible, especially in the higher field regions. For example, in the upper HTS-coils 12 shown in
(35) In a coil design of a 20 T hybrid dipole for certain accelerators, lower-field blocks may be made with conventional Low Temperature Superconductors (LTS) to reduce cost, and the high-field blocks may be made with HTS, see
(36) Preliminary Model Calculations with COMSOL
(37) A preliminary finite-element-analysis using COMSOL's AC/DC Module (www.comsole.com) quantifies the reduction in field perturbation that might be expected from tape alignment.
(38) Flat, Tilted Coils.
(39) The tilting may be applied to make the HTS-tape-width 6 substantially parallel to the magnetic-field-lines 18, with various features as described above. By using placed, flat, rectangular tilted-HTS-coil-cross-sections 22 a substantial alignment with the magnetic-field-lines 18 can be achieved. This embodiment may be simple to manufacture. However curvature or divergence in the magnetic-field-lines 18 may lead to some remaining misalignment.
An Embodiment—Curving and Tilting the Coils
(40) An embodiment could involve curving and tilting the HTS-tape 2 to align the HTS-tape 2 large-dimension, which in this case is curved, with the magnetic-field-lines 18.
(41) The curving of the HTS-tape 2 need not be uniform or continuous, as the goal is to align the HTS-tape 2 large-dimension, which in this case is curved, with the magnetic-field-lines 18.
(42) Curved, Tilted Coils.
(43) The curving and tilting may be applied to make the HTS-tape-width 6 substantially parallel to the magnetic-field-lines 18, with various features as described above. By using a placed curved-and-titled-HTS-tape-block-cross-section 30 a substantial alignment with the magnetic-field-lines 18 can be achieved. This embodiment may allow alignment to curved magnetic-field-lines 18 while carefully forming the support structures to manufacture it. However, any divergence in the magnetic-field-lines 18 may lead to some remaining misalignment.
An Embodiment—Wedge Separation of Flat Windings and Tilting of the Coils
(44) An embodiment could involve placing nonconducting wedge-shaped-material 32 which may be triangular in shape within the HTS-coil 12 in order to tilt portions of the HTS-tape 2 with respect to other portions, and then further tilting the block to substantially align it with the magnetic-field-lines 18.
(45) Flat, Wedge-Separated, Tilted Coils.
(46) Wedge-separation with nonconducting wedge-shaped-material 32 and tilting of the HTS-coil 12 may be applied to make the HTS-tape-width 6 substantially parallel to the magnetic-field-lines 18, with various features described above. By using a placed tilted-wedge-separated-HTS-tape-block-cross-section 36 a substantial alignment with the magnetic-field-lines 18 can be achieved. This embodiment may allow alignment to divergent magnetic-field-lines 18.
An Embodiment—Wedge Separation of Curved Windings and Tilting of the Coils
(47) An embodiment could involve forming the nonconducting curved-and-wedge-shaped-material 38 within the HTS-coil 12 in order to curve and tilt portions of the HTS-tape 2 with respect to other portions, and then further tilting the block to substantially align it with the magnetic-field-lines 18.
(48) Curved, Wedge-Separated, Tilted Coils.
(49) Wedge-separation with nonconducting curved-and-wedge-shaped-material 38 and tilting of the HTS-coil 12 may be applied to make the HTS-tape-width 6 substantially parallel to the magnetic-field-lines 18, with various features as described above. By using a placed tilted-curved-and-wedge-separated-HTS-tape-block-cross-section 42 a substantial alignment with the magnetic-field-lines 18 can be achieved. This embodiment may allow alignment to curved and divergent magnetic-field-lines 18, making it a versatile embodiment and the one that can align the HTS-tape-width 6 to the magnetic-field-lines 18.
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(51) If the result, in step 1511 is yes, in step 1515 the curved tapes separated by curved and wedge shaped spacers are aligned with the magnetic field, and if the result in step 1511 is no, in step 1517 the curved tapes are aligned (without the spacers) with the magnetic field.
(52) If the result in step 1513 is yes, in step 1519, the flat tapes separated by wedge shaped spacers are aligned with the magnetic field, and if the result, in step 1513 is no, in step 1521 the flat tapes are aligned (without the spacers) with the magnetic field.
(53) Next, in step 1523 the High field magnetic dipole is operated
(54) The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the above detailed description.
(55) It will be understood that any geometric shape, which is expressly or implicitly disclosed in the specification and/or recited in a claim is intended for illustration only and is not intended to be in any way limiting. For example, the term wedge is intended to include shapes that approximate wedges and/or trapezoids.
(56) It will be understood that any compound, material or substance which is expressly or implicitly disclosed in the specification and/or recited in a claim as belonging to a group or structurally, compositionally and/or functionally related compounds, materials or substances, includes individual representatives of the group and all combinations thereof.
(57) While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.