EP2150829A1 - Agencement d'aimants destinés à créer un champ magnétique permanent homogène pouvant être utilisé en résonance magnétique nucléaire - Google Patents

Agencement d'aimants destinés à créer un champ magnétique permanent homogène pouvant être utilisé en résonance magnétique nucléaire

Info

Publication number
EP2150829A1
EP2150829A1 EP07725713A EP07725713A EP2150829A1 EP 2150829 A1 EP2150829 A1 EP 2150829A1 EP 07725713 A EP07725713 A EP 07725713A EP 07725713 A EP07725713 A EP 07725713A EP 2150829 A1 EP2150829 A1 EP 2150829A1
Authority
EP
European Patent Office
Prior art keywords
magnets
main
ring
magnetic
magnet arrangement
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP07725713A
Other languages
German (de)
English (en)
Inventor
Bertram Manz
Frank Volke
Martin Benecke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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 Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of EP2150829A1 publication Critical patent/EP2150829A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
    • G01R33/383—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field using permanent magnets

Definitions

  • the invention relates to a magnet arrangement for generating an NMR-capable homogeneous permanent magnetic field.
  • NMR imaging methods as well as corresponding devices are used i.a. for nondestructive material and structural analysis of objects that may consist of crystalline, glassy materials or soft materials, such as elastomers, or liquids or biological materials.
  • a known NMR method as well as a related device can be found in DE 199 39 626 A1, in which a transportable NMR device is described.
  • the known device provides two spaced-apart permanent magnets, which serve to generate a stationary magnetic polarization field. Between the permanent magnets, an RF coil assembly and two gradient coils are provided, the latter are used to produce one, the stationary magnetic polarization field overlying magnetic gradient field, which is operated pulsed for spatially resolved NMR measurement at time intervals.
  • the RF coil arrangement which also serves as a receiving coil in addition to the generation of the RF alternating field, high-frequency signals that are caused by nuclear resonant processes occurring in the interior of the sample, received and brought by means of an evaluation unit for visual representation.
  • the nuclear resonant processes occurring in the interior of the sample are mainly due to nuclear spin interactions of the hydrogen atoms with the stationary magnetic polarization field, which are based on a targeted energetic RF excitation by the RF alternating field, and can in the evaluation in the broadest sense with within the analyzed sample volume existing hydrogen concentration.
  • the above-described NMR device in the form of a transportable device permits a planar examination of an object by overlaying the object surface
  • the object volume to be analyzed is restricted to only a few millimeters due to the only very small penetration depth of the magnetic fields that can be generated by the NMR device. It is certainly possible to improve the penetration depth into the object to be examined by appropriate size dimensioning of the permanent magnets used, but such scaling measures are only able to insignificantly influence the actual magnetic penetration depth.
  • the NMR device is unusable by larger and thus heavier permanent magnets for portable use.
  • the invention has for its object to further form a magnet assembly for generating an NMR-enabled homogeneous permanent magnetic field, so that the arrangement is variable in size and in particular also transportable.
  • the magnetic field generated by the magnet arrangement for NMR measurements should have a particularly pronounced homogeneity and magnetic field strength.
  • the arrangement should be possible with commercial magnets as possible, so that they should be simple, inexpensive and moreover robust in handling.
  • the arrangement should in particular be miniaturized and enable NMR measurements on small objects, preferably on biological samples.
  • the magnet arrangement according to the invention for generating an NMR-capable homogeneous magnetic field is characterized by two permanent magnets, which are referred to below as main magnets. Both main magnets each have at least one magnetic surface area, wherein the magnetic surface areas of both main magnets are arranged parallel and at a distance from each other, so that the main magnets define a space on both sides by their magnetic surface areas.
  • the main magnets are each advantageously designed as Zylindervollmagnete and spatially supported such that in each case an end-side cylindrical surface, which also represents a magnetic pole, coaxial and spaced from the frontal cylindrical surface of the respective another permanent magnet is arranged, wherein the magnet poles of both coaxially opposite end faces are selected to have opposite poles, so that a substantially cylindrical, homogeneous magnetic field in the space between the two cylindrical magnetic pole surfaces can form.
  • At least two further, ring-shaped permanent magnets are provided, which are referred to below as ring magnets and which are arranged coaxially to each other and together define a ring inner space radially.
  • the ring magnets are arranged with respect to both main magnets with their inner ring surfaces facing axially on both sides of the main magnet space limited radially and thus enclose the gap radially.
  • the magnetic polarity of the ring magnets is related chosen to the magnetic polarity of the main magnets so that the magnetic fields of the main and ring magnets in the limited or enclosed by the magnet space constructively overlay, ie the magnetic flux lines of the magnetic fields from the main and ring magnets are the same orientation at least within the ring interior.
  • Both ring magnets which peripherally surround the main magnetic field generated by the main magnets, can advantageously be positioned both axially relative to the center axis of the ring or positioned independently of one another in order to achieve optimized homogenization of the magnetic field enclosed by the permanent magnet arrangement.
  • a suitable fixing mechanism is provided, which is provided at least on a ring magnet, by which the at least one ring magnet is axially positionable against the magnetic force acting between the two ring magnets.
  • both of the frontally opposed main magnets can be positioned with respect to their relative position with the aid of a suitably designed fixing mechanism.
  • a further magnet arrangement designed in accordance with the invention provides a plurality of rod-shaped permanent magnets, each having a rod longitudinal axis, referred to below as rod magnets, which in principle may have any rod cross-section, but in a particularly advantageous manner as a cylindrical Full magnets are formed.
  • the bar magnets are uniformly distributed, arranged along a circumferentially closed perimeter line with a respective rod longitudinal axis oriented perpendicular to a surface inscribable by the circumferential line, wherein the individual bar magnets have a respective rectified magnetic pole.
  • the plurality of individual bar magnets radially adjoin an inner space which at least partially surrounds the space bounded on both sides by the magnetic surface areas of both main magnets, with the magnetic fields of the main and bar magnets structurally overlapping.
  • the plurality of individual bar magnets along a circular line whose circle diameter is equal to or greater than the diameter of the advantageous circular magnetic surface areas of both axially opposed main magnets.
  • sample volume For the purpose of an NMR test on a sample, for example of seed, it is necessary to introduce the sample as centrally as possible within the volume enclosed by the two permanent magnet systems, the so-called sample volume.
  • sample volume it is necessary to provide an RF coil arrangement to generate and detect the NMR signals of the sample.
  • at least one main magnet can be displaced axially in order in this way to have a one-sided access to the magnet arrangement otherwise largely to create enclosed sample volumes. It is also possible to guide the RF coil arrangement through corresponding feedthroughs through at least one main magnet or to connect it to it.
  • the particular advantage of the structurally simple design of the magnet arrangement relates to the possibility of miniaturization, so that NMR investigations at almost any location and with simple and therefore inexpensive means are feasible.
  • the solution according to transportable permanent magnet arrangement offers a favorable implementation possibility for carrying out NMR studies that previously failed due to the high cost associated with previous solutions.
  • the mobile permanent magnet system which is designed for NMR investigations, can be used in particular in the pharmaceutical and chemical industry, for example in quality control. At the same time, investigations in the fields of biotechnology, material testing, medicine, wood and construction, food technology and composite materials, to name just a few applications, can be carried out here.
  • Fig. 1 shows a schematic longitudinal section through a
  • FIG. 2 perspective view of a permanent magnet system with a
  • FIG. 1 shows a first exemplary embodiment for realizing the permanent magnet arrangement according to the invention, with which it is possible to produce a very strong and homogeneous magnetic field without electrical components, ie. H. exclusively based on permanent magnets, which can be used for NMR investigations.
  • the permanent magnet arrangement has two so-called.
  • main magnets 1, 2 designed as solid cylinders are mounted so as to be longitudinally displaceable along their common cylinder axis 3, so that their mutual axial spacing is controllably adjustable.
  • the magnetic poles of both opposing end faces of the main magnets 1, 2 are selected to have opposite polarity.
  • ring magnets 4, 5 which are shaped and dimensioned in such a way that they radially surround a ring interior, which surrounds the ring magnet between the two main magnets 1 , 2 limited space on both sides, d. H. the ring inner surfaces of the ring magnets 4, 5 enclose the space bounded on both sides by both main magnets relative to the cylinder axis 3 in the radial direction.
  • the ring inner cross-section with the frontal cylindrical surfaces of the main magnets 1, 2 coincide, but much more is that the Ring magnets 4, 5 enclosed by both main magnets 1, 2 on both sides gap gapless or cleaved enclosing to effect in this way a significant strengthening of the two main magnet 1, 2 forming main magnetic field and also contribute to a significant homogenization of the main magnetic field.
  • the ring magnets 4, 5 are for adjustment purposes at least relative to each other and also relative to the main magnet 1, 2 axially displaceable positionable. Since the ring magnets 4, 5 have a magnetization, by which they are held together axially, it is necessary for purposes of adjustment to provide a fixing mechanism, not shown, which is able to accomplish a spatial positioning of the ring magnets 4, 5 individually. Thus, in particular by a fine adjustment of the ring magnets 4, 5 both the strength and the homogeneity of the main magnetic field forming between the two main magnets 1, 2 can be optimized.
  • the volume enclosed by both main magnets and the ring magnets 4, 5 shown in FIG. 1 corresponds to the sample volume for carrying out NMR investigations, which can be carried out in a manner known per se.
  • the solution-based permanent magnet arrangement can be miniaturized in an advantageous manner.
  • sample volumes down to the ⁇ m range can be realized, in which the smallest objects can be examined by NMR technique. It is also possible to form the sample volume by suitable dimensioning of the magnets in the cm range, ie with sample volumes of up to 200 cm 3 .
  • FIG. 1 As an alternative to the use of the ring magnets 4, 5 shown in FIG. 1, another embodiment for realizing the permanent magnet arrangement according to the invention is shown in FIG. Thus, it is assumed in this case that instead of the ring magnets, a plurality of individual cylinder-shaped bar magnets 6 along a circular line 7 is arranged distributed evenly, wherein the magnetic polarity of the individual bar magnets 6 is the same orientation to the main magnet 1, 2 as shown in Figure 2. Not necessarily, it is necessary to form the bar magnets 6 cylindrical. Thus, deviating from the circular shape magnetic cross sections are conceivable.

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Physical Vapour Deposition (AREA)

Abstract

L'invention concerne un agencement d'aimants destinés à créer un champ magnétique permanent homogène pouvant être utilisé en résonance magnétique nucléaire. L'invention est caractérisée en ce que deux aimants permanents, désignés ci-après aimants principaux, comportent chacun une zone superficielle de pôle magnétique, ces zones superficielles de pôle magnétique sont parallèles et espacées l'une de l'autre, de manière que les aimants principaux délimitent des deux côtés un espace intermédiaire entre leurs zones superficielles de pôle magnétique, les surfaces de pôle magnétique des aimants principaux présentent une polarité magnétique mutuellement opposée, au moins deux aimants permanents annulaires, désignés ci-après aimants annulaires, sont coaxiaux et délimitent radialement ensemble un espace intérieur annulaire, les aimants annulaires sont disposés relativement aux deux aimants principaux de façon que l'espace intérieur annulaire enferme au moins partiellement l'espace intermédiaire et que les champs magnétiques des aimants principaux et des aimants annulaires soient superposés.
EP07725713A 2007-05-31 2007-05-31 Agencement d'aimants destinés à créer un champ magnétique permanent homogène pouvant être utilisé en résonance magnétique nucléaire Withdrawn EP2150829A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2007/004832 WO2008145167A1 (fr) 2007-05-31 2007-05-31 Agencement d'aimants destinés à créer un champ magnétique permanent homogène pouvant être utilisé en résonance magnétique nucléaire

Publications (1)

Publication Number Publication Date
EP2150829A1 true EP2150829A1 (fr) 2010-02-10

Family

ID=38434467

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07725713A Withdrawn EP2150829A1 (fr) 2007-05-31 2007-05-31 Agencement d'aimants destinés à créer un champ magnétique permanent homogène pouvant être utilisé en résonance magnétique nucléaire

Country Status (5)

Country Link
US (1) US8390289B2 (fr)
EP (1) EP2150829A1 (fr)
CA (1) CA2688836A1 (fr)
NO (1) NO20093406L (fr)
WO (1) WO2008145167A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2962846B1 (fr) * 2010-07-16 2014-10-17 Commissariat Energie Atomique Dispositif d'aimant permanent de creation d'un champ magnetique homogene deporte
DE102016203588A1 (de) * 2016-03-04 2017-09-07 Bruker Biospin Gmbh Streufeldarme Permanentmagnetanordnung für MR-Apparaturen
WO2021055473A1 (fr) 2019-09-16 2021-03-25 Toyota Motor Engineering & Manufacturing North America, Inc. Plot de base de transfert d'énergie sans fil dynamique
CN113155883B (zh) * 2021-04-20 2023-03-14 吉林大学 磁共振浅地表土壤水和烃污染物含量测量装置及方法

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US4411270A (en) * 1978-11-20 1983-10-25 Damadian Raymond V Apparatus and method for nuclear magnetic resonance scanning and mapping
DE3566185D1 (en) * 1984-04-11 1988-12-15 Sumitomo Spec Metals Magnetic field generating device for nmr-ct
DE3434150A1 (de) 1984-09-18 1986-03-27 Kernforschungsanlage Jülich GmbH, 5170 Jülich Verfahren und vorrichtung zur abtrennung von wasserstoff aus einem stoffgemisch, insbesondere einer gasmischung
FR2611975B1 (fr) 1987-03-03 1995-02-17 Commissariat Energie Atomique Systeme d'aimants permanents pour un champ magnetique intense
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
JP2726857B2 (ja) 1989-01-10 1998-03-11 住友特殊金属株式会社 Ｍｒｉ用磁界発生装置
US4994777A (en) * 1989-11-14 1991-02-19 The United States Of America As Represented By The Secretary Of The Army Enhanced magnetic field within enclosed cylindrical cavity
US6150911A (en) * 1996-07-24 2000-11-21 Odin Technologies Ltd. Yoked permanent magnet assemblies for use in medical applications
US6163154A (en) 1997-12-23 2000-12-19 Magnetic Diagnostics, Inc. Small scale NMR spectroscopic apparatus and method
US6489872B1 (en) 1999-05-06 2002-12-03 New Mexico Resonance Unilateral magnet having a remote uniform field region for nuclear magnetic resonance
KR100319923B1 (ko) * 1999-05-10 2002-01-09 윤종용 자기공명영상장치용 자기장 발생 장치
DE19939626C2 (de) 1999-08-20 2002-09-26 Intech Thueringen Gmbh Verfahren zur Erzeugung von Meßsignalen in Magnetfeldern mit einem NMR-Mouse-Gerät
US6518867B2 (en) * 2001-04-03 2003-02-11 General Electric Company Permanent magnet assembly and method of making thereof
DE10224192A1 (de) 2002-05-31 2003-12-18 Fraunhofer Ges Forschung Bildgebendes NMR-Verfahren sowie NMR-Vorrichtung
NZ520114A (en) 2002-07-11 2004-11-26 Victoria Link Ltd an magnetic assembly for an NMR apparatus having an array of permanent magnets disposed about an axis
US6859123B2 (en) * 2003-04-03 2005-02-22 Ge Medical Systems Global Technology Company, Llc Methods and apparatus for positioning permanent magnetic blocks
CN100350522C (zh) * 2004-05-18 2007-11-21 北京泰杰磁电研究所 一种磁共振成像磁体及构成方法
US7759938B2 (en) * 2007-02-05 2010-07-20 Morpho Detection, Inc. Apparatus and method for varying magnetic field strength in magnetic resonance measurements
FR2949604B1 (fr) * 2009-08-28 2012-03-02 Commissariat Energie Atomique Structure aimantee axisymetrique induisant en son centre un champ homogene d'orientation predeterminee

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Also Published As

Publication number Publication date
US20100231219A1 (en) 2010-09-16
US8390289B2 (en) 2013-03-05
WO2008145167A1 (fr) 2008-12-04
CA2688836A1 (fr) 2008-12-04
NO20093406L (no) 2009-12-17

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