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Magnetics, IEEE Transactions on

Issue 5 • Date September 1981

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Displaying Results 1 - 25 of 213
  • [Front cover and table of contents]

    Page(s): 0
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  • Welcome to MT-7

    Page(s): 1531
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    Freely Available from IEEE
  • Editors' comments

    Page(s): 1535
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    Freely Available from IEEE
  • Chairman's impressions

    Page(s): 1536
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  • Status of development of superconducting AC generators

    Page(s): 1551 - 1559
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    Superconducting generators are being developed throughout the world. The present status of this effort is reviewed and the different ways in the development programs of the leading manufacturers are outlined. The report describes tne comprehensive multi-step program of advanced turbogenerator technology established by KWU/Siemens which includes the manufacture and testing of a superconducting rotor of full commercial size but reduced active length. Rotor design and materials as well as the test facilities are shown. Some major problems of superconducting generators are discussed and the technical and economic benefits in comparison with conventional generators are described. View full abstract»

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  • Superconducting magnets for accelerators, beam lines and detectors

    Page(s): 1560 - 1566
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    After twenty years of intensive R & D, superconducting magnets are now widely used in High Energy Physics laboratories. Large detectors and spectrometers have been the first area of successful application. New giant accelerators under construction or planned are definitely based on superconducting components whilst the use for beam lines appears more restricted to special purpose elements. A review of these various applications is presented. View full abstract»

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  • Long term experience on the superconducting magnet system for the CELLO detector

    Page(s): 1567 - 1570
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    A large superconducting magnet system has been installed and is currently operated at the PETRA storage ring (Desy/Hamburg) for the CELLO detector. This system has been carried out as a joint collaboration of CEN/, Saclay and ITP/Karlsruhe and includes as main components a large "thin wall" solenoid cooled by force flow in a pipe bonded to the winding, two bath-cooled compensating solenoids, a 450 W liquifier-refrigerator unit and all connecting lines and appropriate control equipment designed for long-term automatic operation. The system has been in operation for nearly two years with continuous runs exceeding three months and has provided considerable technical experience. View full abstract»

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  • Design of epoxy-free superconducting dipole magnets and performance in both Helium I and pressurized Helium II

    Page(s): 1571 - 1574
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    Three model superconducting dipole magnet 1m long, without iron, having a bore diameter of 76 mm have been built without epoxy resins or other adhesives and tested in He I and He II. The conductor is the 23-strand Rutherford-type cable used in the Fermilab Doubler Saver magnets, and is insulated with Mylar and Kapton. The two-layer winding is highly compressed by a system of structural support rings and tapered collets. Little "training" was required to reach quench currents greater than 95 percent of "short sample" in Helium I. The maximum quench current in He II is increased 20 to 30 percent, compared with He I operation at 4.4 K. Test results are given on cyclic losses, heater-induced quenches, and charge-rate effects. View full abstract»

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  • Upgraded coil configuration for ISABELLE magnets

    Page(s): 1575 - 1578
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    Achievement of the design field of 5 T in the ISABELLE dipole magnets is turning out to be more arduous than expected and several avenues of improvement are being pursued. One possibility for improving training and peak field performance is discussed in this paper. It has been recognized that the inert spacers with their adjacent active turns in the cosine magnet windings can be replaced by a double thickness braid operating at approximately half-current density in 46 of the 190 turns. Since the high-field region occurs in the low current density turns near the poles, a performance improvement can be expected. It has been verified that the proposed coil configuration satisfies the field requirements and details thereof are given. Results from an experimental magnet in which superconducting spacer turns are used to simulate half-current density windings are presented. Construction of thick braid coils is being planned and the status of these magnets is reviewed. View full abstract»

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  • Magnet systems for the Daresbury synchrotron radiation source

    Page(s): 1579 - 1586
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    The design, production and testing of the main dipole and quadrupole magnets for a 2 GeV electron storage ring are described, with particular emphasis on the integrated field performance including the optimisation of magnet ends. In addition fast pulsed kicker and septum magnets for control of injection and extraction processes in both the storage ring and its booster synchrotron injector are treated. All magnets are now installed and operating routinely in the new Synchrotron Radiation Source at Daresbury. View full abstract»

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  • Construction of the S.I.N. ring injector cyclotron magnet system

    Page(s): 1587 - 1590
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    The S.I.N. ring injector cyclotron consists of four sector magnets. Magnetic field calculations were carried through with the computer program POISSON. For the construction of the magnets warm-rolled heavy plats are used. There are three correction elements: equalizing coils, side shims and trim-coils. View full abstract»

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  • Multipole fields in the antiproton accumulator magnet system

    Page(s): 1591 - 1594
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    The Antiproton Accumulator is a very large aperture storage ring in which antiprotons are collected over a wide momentum range, stochastically cooled and stacked. The optical properties must be precisely realised and require a variety of high order field components. The very wide aperture and a lack of available space, preclude the use of separate sextupoles and octupoles to provide these corrections. One of the sextupole components was incorporated into the pole profile of the wide elliptic quadrupoles the left-right symmetry of which was thus broken. The other non linear components were produced by variation of the effective length of the dipoles and quadrupoles and achieved in practice with detachable end shims. View full abstract»

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  • A 5 Tesla superconducting wiggler magnet

    Page(s): 1595 - 1598
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    The design, construction and testing of a three pole superconducting magnet is described. Integral field measurements are compared with computed predictions. Integration of the magnet with its associated refrigeration system and the storage ring is outlined. View full abstract»

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  • Design and test of a 700 mm long hexapole composed of rectangular rare earth cobalt permanent magnets

    Page(s): 1599 - 1602
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    A hexapolar magnet with inner diameter of 80 mm and an air gap inductance of > 400 mT on the pole faces is described. This magnet consists of six parallelepiped rare earth cobalt permanent magnet bars, 17 × 700 mm2in cross section and 42.1 mm in height. The whole device, which is used as part of an ECR-Heavy Ion Source, is placed into a magnetic mirror field with strong axial field strength. To assure a proper superposition of the hexapole field and mirror field, no iron Circuit could be used. The radial and axial field distribution inside the hexa-pole magnet was measured, and compared with calculated data. The variation of field strength, especially the variation of lines with constant field strength as a function of both the height and width of the magnets is discussed. View full abstract»

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  • Design and test results of a pulsed quadrupole magnet with 2 µs rise time

    Page(s): 1603 - 1605
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    Major polarization losses will be encountered during acceleration of polarized protons in the Brookhaven AGS due to eight intrinsic depolarizing resonances. Pulsing a set of 12 vertical tune shift quadrupole magnets with a 2μs rise time, 3 ms fall, and 60 ms repetition rate should reduce these losses. [1] This requires a gradient of 1.87 T/M over the 8.89 × 12.7 cm vacuum chamber. View full abstract»

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  • H-type dipole model for future plan at KEK

    Page(s): 1606 - 1609
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    For the bending magnet of the electron ring of the so-called TRISTAN project at KEK, the H-type dipole, full scale model with 4 m in length, has been investigated at first to examine the feasibility to the electron storage ring from some points such as magnet performance, accessibility for the field measurement and vacuum chamber installation, manufacturing problem and magnet cost. Here, the magnet performance is treated. To measure the magnetic field inside the air gap, the specially designed flip coils were used. Fields of 11 points at the same longitudinal positions could be measured at once by rotating probe containing 11 flip coils on its axis. View full abstract»

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  • Design and magnetic results on a 3 Tesla, 10 Weber spectrometer magnet at Saclay

    Page(s): 1610 - 1613
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    A big spectrometer magnet, three hundred tons, has been successfully designed and measured at Saclay. Its main features are a fixed working induction of 3 Tesla and a total flux of 10 Weber. The coils are conventional and for the yoke we use a scrapped cyclotron. The spectrometer is of an Elbek type and its optic characteristics are a momentum analysis range from 0.6 to 1.4 GeV/c, with a 5.10-4resolution. The angular analysis lies between -5° and 65° around the target. The magnetic study and optimisation of the magnet has been done with Poisson, bidimensional code and Ledi which is a simplified three dimensional code developed for fully saturated iron magnets. View full abstract»

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  • Large scale fabrication of superconductors

    Page(s): 1614 - 1621
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    Beginning with large quantity fabrication the fabrication steps of monolithical NbTi and Nb3sn solid diffusion conductors melting, copper cladding, billet assembling, extrusion, drawing, annealing, twisting and calibration are discussed regarding reproducibility and reliability of the physical properties over long length. An important point is the compatibility of the fabrication parameters with the physical properties optimization treatment. Large cross section high current density conductors and special conductors containing multiple materials for strengthening and reduction of losses fabricated by cabling and special techniques will be discussed. View full abstract»

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  • Filament-size dependent critical current of multifilamentary Nb3Sn conductors

    Page(s): 1622 - 1624
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    The critical current densityjmin{c}max{ov}of multifilamentary Nb3Sn conductors depends on the diameter of the filaments. At low fields (less than about 12 T)jmin{c}max{ov}increases with decreasing filament diameter because of the finer grain size. At high fieldsjmin{c}max{ov}increases with increasing filament diameter. Measurements of the critical current under externally applied tensile stress revealed that changes of the internal compression of the Nb3Sn within the composite account for this effect. The larger the filament diameter, the smaller the compressive strain, the higher the upper critical field and thereforejmin{c}max{ov}at high fields. The decrease of compressive strain with increasing filament size results from a decrease in the yield stress of the bronze which is caused by an increase in grain size of the bronze between the filaments. View full abstract»

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  • Influence of hydrogen on the current density of Nb3Sn multifilamentary conductors

    Page(s): 1625 - 1627
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    The overall current density of Nb3Sn multifilamentary conductors heat-treated with hydrogen and argon is quite different. At flux densities above 11 T hydrogen samples carry more current than argon samples. below 11 T argon samples are superior to hydrogen samples. The transition temperature of hydrogen samples is generally found to be some tenths of a Kelvin below that one of the argon samples. X-ray investigations at room temperature indicate an increase of the lattice spacing in hydrogen samples corresponding to a growth of the unity cell up to 0.6% . The critical current of hydrogen samples undergoing tensile stress will increase in a way similar to argon samples. View full abstract»

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  • Laboratory scale solenoids with multifilamentary Nb3Sn superconductors

    Page(s): 1628 - 1631
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    By the bronze technique Nb3Sn multifilamentary conductors with different numbers and densities of filaments and partly with an integrated CuTa stabilization were fabricated. For currents exceeding 1000 A at 10 T we have manufactured fully transposed and calibrated flat cables with different numbers of strands and different ratios of superconducting to CuTa stabilizing strands. From long lengths (km) of these cables we have fabricated solenoids with manifold graded windings using the wind-and-react-technique and a final vacuum impregnation after reaction. Two different variants of this technique will be described. Magnetic flux densities up to 15 T at 4.2 K in a free bore of 40 mm diameter have been reached in a 7 T NbTi background field. The solenoids attained the short sample current within some percent requiring only short training on initial excitation but no training after heating to room temperature. High excitation speeds were obtained without degradation of the quench current. View full abstract»

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  • A V3Ga-NbTi magnet system with different currents from one power supply

    Page(s): 1632 - 1634
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    In recent years the manufacturing of Nb3Sn or V3Ga composite wires by the bronze process has been mastered. Nb3Sn was investigated more intensively than V3Ga [1,2] although in high fields V3Ga is expected to be superior [3]. Accordingly V3Ga tape was used in a 17.5 Tesla magnet [4] and multifilamentary V3Ga conductor in a 10 Tesla magnet [5]. In this paper we describe an 11 Tesla V3Ga-NbTi magnet system, the V3Ga conductor being produced in our laboratory [6]. A numerical quench analysis for the system is presented. View full abstract»

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  • Performance of a small V3-Ga tape coil in high magnetic fields between 4.2K and 1.9K at atmospheric pressure

    Page(s): 1635 - 1637
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    The critical current in short samples of different lots of commercial V3-Ga tapes has been measured in magnetic fields between 16 and 20 Tesla at 4.2K and 1.9K;a coil using 200 meters of tape has been built and tested in the magnetic field of a resistive coil generating commonly 13.0 Tesla. The results at 4.2K and 1.9K in superfluid liquid helium under one atmosphere are presented. View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics publishes research in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology