WO2021098896A1 - Agencement d'aimants permanents bipolaires pour donner un réseau et utilisation associée - Google Patents

Agencement d'aimants permanents bipolaires pour donner un réseau et utilisation associée Download PDF

Info

Publication number
WO2021098896A1
WO2021098896A1 PCT/DE2020/000259 DE2020000259W WO2021098896A1 WO 2021098896 A1 WO2021098896 A1 WO 2021098896A1 DE 2020000259 W DE2020000259 W DE 2020000259W WO 2021098896 A1 WO2021098896 A1 WO 2021098896A1
Authority
WO
WIPO (PCT)
Prior art keywords
permanent magnets
pole
pole plates
pole permanent
array according
Prior art date
Application number
PCT/DE2020/000259
Other languages
German (de)
English (en)
Inventor
Earl Babcock
Olaf HOLDERER
Original Assignee
Forschungszentrum Jülich GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Forschungszentrum Jülich GmbH filed Critical Forschungszentrum Jülich GmbH
Priority to EP20816381.6A priority Critical patent/EP4062432A1/fr
Publication of WO2021098896A1 publication Critical patent/WO2021098896A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/02—Permanent magnets [PM]
    • H01F7/0273—Magnetic circuits with PM for magnetic field generation
    • H01F7/0278—Magnetic circuits with PM for magnetic field generation for generating uniform fields, focusing, deflecting electrically charged particles

Definitions

  • the invention relates to an arrangement of two-pole permanent magnets to form an array and its use.
  • Homogeneous magnetic fields can be generated, for example, by means of Halbach magnets [“Application of permanent magnets in accelerators and electron storage rings (invited)” Klaus Haibach Journal of Applied Physics 57, 3605 (1985)] or dipole-like magnet systems with two columns or with two rows of Columns of permanent magnets [“Layout and performance often the polarizing guide system for the J-NSE spectrometer at the FRM II”, O. Holderer et al Nuclear Instruments and Method in Physics Research A 586 (2008) 90-94].
  • the size of the region with a high homogeneous field of such a system is limited by the material properties, and the long-range stray fields in the external area can lead to interference with other components and processes outside the magnet system or to undesired interactions.
  • the devices with which homogeneous magnetic fields are generated are spatially very extensive, which is why they also enclose relatively large volume elements and lead to long-range stray fields which impair the homogeneity of the magnetic field.
  • the magnetic fields can also lead to undesired interactions with components and processes outside the magnetic system to generate a homogeneous magnetic field.
  • the magnetic field strength in the volume element in which the homogeneous magnetic field is to be generated should be increased.
  • a device is to be made available which can enclose smaller volume elements and which can be designed to be structurally smaller. Based on the preamble of claim 1 and the subordinate claims, the object is achieved according to the invention with the features specified in the characterizing part of these claims.
  • two two-pole permanent magnets of the same magnetic orientation which form a pair, are arranged between two pole plates in an array so that they enclose a volume element with the pole plates, which is perpendicular to the plane delimited by the two-pole permanent magnets and the pole plates , is open.
  • the device By choosing the dimensions of the device components, the device can be made structurally small and the magnetic field strength in the enclosed volume element can be increased.
  • the magnetization is carried out with two poles of high permeability.
  • the far field is thereby compensated and falls significantly faster than in the standard solution according to the state of the art, in which no magnets with anti-parallel alignment are positioned on the outside of the pole plates.
  • the far field With the same internal field, which is located as a volume element between the pole plates and the permanent magnets arranged between the pole plates, the far field is lower by more than an order of magnitude, ie a power of ten.
  • the arrangement can also be used to increase the strength of the internal field between the poles, while the stray fields continue to be significantly lower than in the standard geometry.
  • the array according to the invention for the enclosed, internal volume element, which is located between the two-pole permanent magnets and the pole plates, compared to the array according to the prior art, which has no external two-pole permanent magnets, otherwise same construction materials and material thickness, a 25% to 35% higher internal magnetic field can be achieved.
  • At least one further two-pole permanent magnet of the same magnetic orientation is arranged in a row behind the two two-pole permanent magnets, which are located between the pole plates, the pole plates covering all two-pole permanent magnets.
  • n two-pole permanent magnets can be arranged one behind the other in a row, the rows preferably running essentially parallel to one another in order to bring about the best possible homogeneity of the magnetic field.
  • the two-pole permanent magnets which are located between the pole plates, are preferably rod-shaped or bar magnets.
  • the two-pole permanent magnets located between the pole plates can consist of a single magnet or at least two two-pole permanent magnets, for example 2, 3 or 4, which are stacked together.
  • the two-pole permanent magnets which are located between the pole plates, can be made of any permanent magnetic material, for example NbFeB, ferrites, AINiCo, or SmCo. It can be permanent magnets or composites, for example magnetic materials that are embedded in plastics, such as magnetic powder in plastics.
  • the two-pole permanent magnets which are located between the pole plates, can have a length of, for example, 1 to 100 cm. In principle, however, the length can be freely selected. In principle, larger dimensions can also be used. So the permanent magnets can be several meters between the pole plates.
  • the two-pole permanent magnets which are located between the pole plates, preferably have a magnetic field strength of 0.2 to 2 Tesla, preferably 1 to 1.3 Tesla.
  • the number n of pairs of two-pole permanent magnets arranged in a row in an array, which are located between the pole plates, can be adapted to the experimental requirements and, depending on the use of the array according to the invention, can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, ... 15, ... 20, ... 30, ... up to 50, but the upper values are in principle open and only limited by practical circumstances.
  • a number of 1 to 50 permanent dipole magnets in each row has proven to be particularly practical.
  • the distances between the individual two-pole permanent magnets or pairs of two-pole permanent magnets, which are arranged one behind the other between the pole plates can be, for example, 0 to 2 cm. Distances of 0 to 1 cm in each case are particularly preferred. A particularly strong magnetic field with good homogeneity can thus be generated. In principle, the distance between the pairs of two-pole permanent magnets should be as small as possible, since a magnetic field with high homogeneity can be achieved in this way.
  • the two-pole permanent magnets between the pole plates, which are located one behind the other in a row, are preferably arranged equidistantly.
  • the external two-pole permanent magnets which are located on the side facing away from the interior, are preferably bar magnets. Instead of a single bar magnet, two, three or more smaller bar magnets can be arranged linearly in a row.
  • the external two-pole permanent magnets are preferably arranged on the pole plate in such a way that they lie on the same sectional plane of the array in which the two-pole permanent magnets are located, which are located between the pole plates.
  • the length of the external two-pole permanent magnets, which are located on the pole plates, can again be between 1 and 100 cm. However, the length can be freely selected as required.
  • the external two-pole permanent magnets should preferably cover the entire section between the two-pole permanent magnets that are located between the pole plates in order to achieve the best possible homogeneity of the magnetic field, based on a plane that goes through two permanent magnets that are between the pole plates. In a less preferred embodiment, however, they can not be arranged on the cutting plane that goes through two permanent magnets that are between the pole plates, but rather shifted to the plane.
  • the distances between the outer two-pole permanent magnets on the outside of the pole plates are preferably the same distances from one another as the pairs of two-pole permanent magnets that are located between the pole plates.
  • the distances between the rows of the two-pole permanent magnets on the outside of the pole plate can be 0 cm to 2 cm. In principle, it is advantageous if the individual, external two-pole permanent magnets are spaced a little apart, since the magnetic field generated in this case achieves a high degree of homogeneity.
  • the two-pole permanent magnets on the outside can each lie on the same cutting plane, which runs through a pair of two-pole permanent magnets lying opposite between the pole plates. It is not imperative that a two-pole permanent magnet is continuously attached to each of these sectional planes, which are parallel to one another. The arrangement should, however, be regular. Embodiments are also possible in which two-pole permanent magnets are arranged with gaps, for example in the manner of a chessboard. However, continuous rows of two-pole permanent magnets are preferred, which are preferably each located on a sectional plane that runs through two opposing two-pole permanent magnets between the pole plates.
  • the number m of two-pole permanent magnets arranged one behind the other in an array, which are located outside the pole plates, can be adapted to the experimental requirements and can for example be 1, 2, 3, 4, 5, 6 depending on the use of the array according to the invention , 7, 8, 9, 1, ... 15, ... 20, ... 30, ... up to 50, but the upper values are in principle open and only limited by practical circumstances.
  • a number of 1 to 50 permanent dipole magnets in each row has proven to be particularly practical.
  • the external two-pole permanent magnets, which are located on the pole plates can be made of any permanent magnetic material, for example NbFeB, ferrite, AINiCo or SmCo. It can be fixed magnets or composites, for example magnetic materials that are embedded in plastics.
  • the field strength of the external two-pole permanent magnets can be from 0.2 to 2 Tesla, preferably 1 to 1.3 Tesla.
  • the volume of the outer two-pole permanent magnets on each outward-facing side of the pole plates is preferably equal to the volume of the pairs of two-pole permanent magnets lined up one behind the other between the pole plates. This applies in particular when the individual external two-pole permanent magnets and two-pole permanent magnets arranged one behind the other have the same magnetization between the pole plates.
  • the magnetization, which is caused by the two-pole permanent magnets, which are arranged between the pole plates, and the magnetization, which is caused by the outer bipolar permanent magnets are caused to have the same amount.
  • the individual parts of the device according to the invention are preferably structurally connected to one another in order to hold them together. This can be achieved, for example, with a frame in which the components are clamped or inserted. This can counteract repulsive forces.
  • the pole plates should have the highest possible permeability.
  • the pole plates with high magnetic permeability should have a saturation above the remanent magnetization of the two-pole permanent magnets located between the pole plates.
  • the pole plates can practically have a thickness of more than 1 mm to, for example, 3 cm.
  • the thickness of the pole plates can, however, also take on other larger values as a function and are freely selectable.
  • the pole plates should also be thick enough so that the permeability for a given magnet arrangement does not go into saturation.
  • a suitable thickness can for example be in an array of NbFeB magnets for a high magnetic field 0.07 Tesla in a volume element of 20 x 40 x 60 cm field 1 - 3 cm. The thickness should be high enough to prevent saturation in the volume of the pole plate material.
  • the strength of the internal field between the pole plates can be adjusted by the volume of the magnets used.
  • the two-pole permanent magnets located between the pole plates are designs with one or more magnetic columns.
  • the magnetic field strength of the external two-pole permanent magnets can be in a range from 0.2 to 2 Tesla, preferably 1 to 1.3 Tesla, in order to achieve a high magnetic field strength in the internal volume element.
  • the magnetic flux that is generated by the two-pole permanent magnets on the outside and that generated by the two-pole permanent magnets between the pole plates should preferably be of the same size.
  • the volume of the two-pole permanent magnets outside the pole plates and the oppositely polarized two-pole permanent magnets between the pole plates in the 4-magnet arrangement according to the invention is the same and the magnets are of the same type and generate comparable magnetic flux, the far fields of the arrangement are particularly good minimized.
  • the internal magnetic field between the pole plates is most homogeneous for a regular and uniform arrangement of the permanent magnets. This is the case, for example, if the permanent magnets between the pole plates are arranged structurally identically and equidistantly and / or the permanent magnets outside the pole plates are structurally arranged identically and equidistantly.
  • the two-pole permanent magnets between the pole plates and the two-pole permanent magnets, which are arranged on the outside of the pole plates facing away from the interior, are then preferably each located on a sectional plane.
  • adding an equal volume of anti-parallel magnets according to the invention affects the pole plates in a 25% to 35% increase in the internal field that is between the pole plates located, from.
  • the total volume of all magnets i.e. the two-pole permanent magnets, which are located between the pole plates and the two-pole permanent magnets, which are located on the outside of the pole plates, are correspondingly reduced depending on the exact geometry. It can thus be achieved that the internal magnetic field is not increased, but the stray field is reduced.
  • the array according to the invention can therefore be used to homogenize the internal magnetic field and / or to reduce the stray field outside the array.
  • the array according to the invention can be used to generate magnetic fields of, for example, up to 2 Tesla.
  • the figures show the device according to the invention in schematic form, as well as magnetic fields generated by the device. It shows:
  • FIG. 1 an array according to the invention.
  • FIG. 2 A side view of the opening of the array according to the invention.
  • FIG. 3 A side view of the array according to the invention.
  • 5a, 5b Magnetic fields generated by the array according to the invention.
  • Figure 2 shows a side view of the opening of the device according to the invention.
  • the same device components have the same numbering.
  • FIG. 3 shows a side view of the device according to the invention.
  • the same device components have the same numbering as in the previous figures.
  • FIG. 4 shows a plan view of the device according to the invention. In it, the same device components have the same numbering as in the previous figures.
  • FIG. 5b shows a model finite element calculation for an internal and external magnetic field which is produced according to the invention in comparison to a corresponding magnetic field in FIG. 5a which was produced according to the method according to the prior art.
  • a central field of 0.055 Tesla is achieved in this embodiment, the isolines are drawn in at a distance of 0.004 Tesla.
  • the side length of Figures 5a and 5b is 1 m.
  • the pole plates (3), (4) are arranged vertically.
  • the two-pole permanent magnets (1), (2) between the pole plates (3), (4) limit the arrangement above and below.
  • the central magnetic field between the pole plates (3), (4) is 0.073 Tesla.
  • Magnetic field to hold the magnetization of a super mirror for neutron polarizers or analyzers can be used as an improved magnet system, which ensures the effect of the super mirror and at the same time significantly reduces the long-range stray fields. For example, the strength of the stray field at a distance of 2 m from the super mirror analyzer is reduced by more than an order of magnitude with a 4-magnet arrangement.
  • a “dipole” system (2-column solution) is considered for a 26 cm high, 12.6 cm wide and 60 cm long super mirror analyzer unit with an internal field between the poles of 0.055 Tesla, which generates a field of 30 pTesla at a distance of 2 m, ie in a similar order of magnitude as the earth's magnetic field.
  • a field of ⁇ 3 pTesla is generated at the same distance. Since these devices are often mobile and some neutron scattering experiments are extremely sensitive to variable external magnetic fields, poor shielding of the magnetic fields can lead to strong disturbances in the vicinity.
  • the solution presented here reduces the strength of the undesired stray fields by more than an order of magnitude, which minimizes the interference of different instruments, in the best case so that mutual interference is completely excluded.
  • a neighboring instrument with a super mirror analyzer with 2 magnetic column arrangement for the magnetic field can cause a phase shift of the polarized neutron beam on the neutron spin echo spectrometer in the order of magnitude of up to 60 °. Stray fields that would be more than an order of magnitude smaller would allow both instruments to operate simultaneously.
  • FIG. 5b shows the stray fields for the geometry described above.

Abstract

L'invention concerne un réseau d'aimants permanents bipolaires (1, 2), au moins deux aimants permanents bipolaires (1, 2) ayant une direction de magnétisation identique et formant une paire sont disposés entre deux plaques polaires (3), (4) de telle sorte qu'ils entourent un élément de volume conjointement avec les plaques polaires (3), (4), ledit élément de volume étant ouvert perpendiculairement au plan qui est délimité par les aimants permanents bipolaires (1, 2) et les plaques polaires (3), (4), sur les côtés des plaques polaires (3), (4) opposés aux aimants permanents bipolaires (1, 2), des aimants permanents bipolaires externes (5, 6) étant situés, dont la magnétisation est opposée à la magnétisation des aimants permanents bipolaires (1, 2) situés entre les plaques polaires (3), (4), et ainsi les champs magnétiques de ceux-ci présentant une orientation antiparallèle.
PCT/DE2020/000259 2019-11-20 2020-10-28 Agencement d'aimants permanents bipolaires pour donner un réseau et utilisation associée WO2021098896A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP20816381.6A EP4062432A1 (fr) 2019-11-20 2020-10-28 Agencement d'aimants permanents bipolaires pour donner un réseau et utilisation associée

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102019008033.5A DE102019008033A1 (de) 2019-11-20 2019-11-20 Anordnung von zweipoligen Permanentmagneten zu einem Array und dessen Verwendung
DE102019008033.5 2019-11-20

Publications (1)

Publication Number Publication Date
WO2021098896A1 true WO2021098896A1 (fr) 2021-05-27

Family

ID=73646028

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2020/000259 WO2021098896A1 (fr) 2019-11-20 2020-10-28 Agencement d'aimants permanents bipolaires pour donner un réseau et utilisation associée

Country Status (3)

Country Link
EP (1) EP4062432A1 (fr)
DE (1) DE102019008033A1 (fr)
WO (1) WO2021098896A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4764743A (en) * 1987-10-26 1988-08-16 The United States Of America As Represented By The Secretary Of The Army Permanent magnet structures for the production of transverse helical fields
EP0289979A1 (fr) * 1987-05-02 1988-11-09 Sawafuji Co., Ltd. Aimants en matière synthétique
DE3875435T2 (de) * 1987-03-03 1993-05-06 Commissariat Energie Atomique Permanentmagnetsystem zur erzeugung eines intensiven magnetfeldes.
DE69319890T2 (de) * 1992-01-13 1999-02-25 Oxford Instr Uk Ltd Bestimmung von gesteinkern-charakteristiken

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4658228A (en) * 1986-05-01 1987-04-14 The United States Of America As Represented By The Secreatry Of The Army Confinement of longitudinal, axially symmetric, magnetic fields to annular regions with permanent magnets
KR101360852B1 (ko) * 2012-08-24 2014-02-11 한국원자력연구원 주기가변 영구자석 언듈레이터

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3875435T2 (de) * 1987-03-03 1993-05-06 Commissariat Energie Atomique Permanentmagnetsystem zur erzeugung eines intensiven magnetfeldes.
EP0289979A1 (fr) * 1987-05-02 1988-11-09 Sawafuji Co., Ltd. Aimants en matière synthétique
US4764743A (en) * 1987-10-26 1988-08-16 The United States Of America As Represented By The Secretary Of The Army Permanent magnet structures for the production of transverse helical fields
DE69319890T2 (de) * 1992-01-13 1999-02-25 Oxford Instr Uk Ltd Bestimmung von gesteinkern-charakteristiken

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
KLAUS HALBACH: "Application of permanent magnets in accerleraors and electron storage rings (invited", JOURNAL OF APPLIED PHYSICS, vol. 57, 1985, pages 3605
O. HOLDERER ET AL.: "Layout and performance oft the polarizing guide system for the J-NSE spectrometer at the FRM II", NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH A, vol. 586, 2008, pages 90 - 94, XP022449498, DOI: 10.1016/j.nima.2007.11.038
POTENZIANI E ET AL: "THE PRODUCTION OF LAMINAR FIELDS WITH PERMANENT MAGNETS", JOURNAL OF APPLIED PHYSICS, AMERICAN INSTITUTE OF PHYSICS, US, vol. 61, no. 8 PART 02A, 15 April 1987 (1987-04-15), pages 3466 - 3467, XP000168457, ISSN: 0021-8979, DOI: 10.1063/1.338755 *
POTENZIANI E. ET AL: "Permanent magnets for magnetic resonance imaging", IEEE TRANSACTIONS ON MAGNETICS, vol. 22, no. 5, 1 September 1986 (1986-09-01), NEW YORK, NY, US, pages 1078 - 1080, XP055773629, ISSN: 0018-9464, DOI: 10.1109/TMAG.1986.1064465 *

Also Published As

Publication number Publication date
DE102019008033A1 (de) 2021-05-20
EP4062432A1 (fr) 2022-09-28

Similar Documents

Publication Publication Date Title
DE102008020107B4 (de) Kompakte supraleitende Magnetanordnung mit aktiver Abschirmung, wobei die Abschirmspule zur Feldformung eingesetzt wird
DE3333955A1 (de) Permanentmagnet-mehrpolgebilde mit einstellbarer staerke
DE102017205485A1 (de) Permanentmagnetanordnung für MR-Apparaturen mit axial und lateral verschiebbaren, drehbar gelagerten Ringbaugruppen
DE102011109949A1 (de) Prüfanordnung zur Wertdokumentprüfung
DE10117595C1 (de) Asymmetrische Anordnung permanentmagnetischer Elemente für eine Magnetresonanzapparatur und Verfahren zur Herstellung einer solchen Magnetanordnung
EP2044455B1 (fr) Dispositif pour l'application d'un champ magnétique à un échantillon
DE3917764C2 (de) Magnetische Trimmanordnung zur Korrektur der harmonischen Komponenten n-ter Ordnung einer Komponente des Hauptmagnetfeldes einer mit magnetischer Kernresonanz arbeitenden Vorrichtung
DE1439579B2 (fr)
DE1283976B (de) Magnetsystem fuer die Erzeugung eines sehr homogenen magnetischen Feldes
DE69929507T2 (de) Hybrid-Wiggler
WO2012156278A1 (fr) Dispositif de production d'un champ magnétique homogène
DE4430017A1 (de) Wien'sches Filter
WO2021098896A1 (fr) Agencement d'aimants permanents bipolaires pour donner un réseau et utilisation associée
DE102014207731A1 (de) Sendeantenneneinrichtung und Magnetresonanztomographieanlage
EP1044702A2 (fr) Bande magnétisée enroulée en forme de spirale
DE2255273C2 (de) Magnetisches Ablenkjoch zum Parallelausrichten der divergierenden Strahlen eines Strahlenbündels elektrisch geladener Teilchen, insbesondere bei einem Elektronenbeschleuniger
DE19854483B4 (de) Vorrichtung zur Erzeugung eines Magnetfeldes in einem Luftspalt
DE2107770C3 (de) Spulenanordnung fur Justier und Korrekturelemente zur elektro magnetischen Beeinflussung von Bundein geladener Teilchen, insbesondere fur Sektorfeldlinsen in Massenspektrometern
EP2823693B1 (fr) Dispositif de déflexion pour la déflexion de particules chargées
DE102020002963A1 (de) Verfahren zur Herstellung eines Seltenerdmagneten
DE102020007560B3 (de) Anordnung von Permanentmagneten zur Erzeugung eines Führungsfeldes für polarisierte Neutronen und deren Verwendung
EP1191345B1 (fr) Arrangement d'aimants supraconducteurs comportant des moyens ferromagnétiques pour homogéniser le champ magnétique
EP0184656A1 (fr) Dispositif magnétique pour la tomographie à résonance de spin nucléaire comportant une structure de blindage à forme approximativement cylindrique
DE102009016949B4 (de) Faraday-Rotator und Anordnung
DE2433678C3 (de) Abtastelement zum Abtasten von Zielkennzeichenmagneten

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20816381

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2020816381

Country of ref document: EP

Effective date: 20220620