A portable Halbach magnet that can be opened and closed without force: The NMR-CUFF

Autoren

Carel W Windt
Helmut Soltner
Dagmar van Dusschoten
Peter Blümler

DOI

10.1016/j.jmr.2010.09.020

ISSN

1090-7807

Ausgabe der Veröffentlichung

1

Zeitschrift

Journal of Magnetic Resonance

Sprache

en

Paginierung

27 - 33

Datum der Veröffentlichung

2011

Status

Published

Herausgeber

Elsevier BV

Herausgeber URL

http://dx.doi.org/10.1016/j.jmr.2010.09.020

Datum der Datenerfassung

2019

Titel

A portable Halbach magnet that can be opened and closed without force: The NMR-CUFF

Ausgabe der Zeitschrift

208

Data source: Crossref

Abstract

Portable equipment for nuclear magnetic resonance (NMR) is becoming increasingly attractive for use in a variety of applications. One of the main scientific challenges in making NMR portable is the design of light-weight magnets that possess a strong and homogeneous field. Existing NMR magnets can provide such magnetic fields, but only for small samples or in small regions, or are rather heavy. Here we show a simple yet elegant concept for a Halbach-type permanent magnet ring, which can be opened and closed with minimal mechanical force. An analytical solution for an ideal Halbach magnet shows that the magnetic forces cancel if the structure is opened at an angle of 35.3° relative to its poles. A first prototype weighed only 3.1 kg, and provided a flux density of 0.57 T with a homogeneity better than 200 ppm over a spherical volume of 5mm in diameter without shimming. The force needed to close it was found to be about 20 N. As a demonstration, intact plants were imaged and water (xylem) flow measured. Magnets of this type (NMR-CUFF = Cut-open, Uniform, Force Free) are ideal for portable use and are eminently suited to investigate small or slender objects that are part of a larger or immobile whole, such as branches on a tree, growing fruit on a plant, or non-metallic tubing in industrial installations. This new concept in permanent-magnet design enables the construction of openable, yet strong and homogeneous magnets, which aside from use in NMR or MRI could also be of interest for applications in accelerators, motors, or magnetic bearings.

Addresses

ICG-3: Phytosphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany. c.windt@fz-juelich.de

Autoren

Carel W Windt
Helmut Soltner
Dagmar van Dusschoten
Peter Blümler

DOI

10.1016/j.jmr.2010.09.020

eISSN

1096-0856

Externe Identifier

PubMed Identifier: 21036637

Open access

false

ISSN

1090-7807

Ausgabe der Veröffentlichung

1

Zeitschrift

Journal of magnetic resonance (San Diego, Calif. : 1997)

Schlüsselwörter

Magnetic Resonance Spectroscopy
Equipment Design
Equipment Failure Analysis
Stress, Mechanical
Magnetics
Miniaturization

Sprache

eng

Medium

Print-Electronic

Online publication date

2010

Paginierung

27 - 33

Datum der Veröffentlichung

2011

Status

Published

Datum der Datenerfassung

2010

Titel

A portable Halbach magnet that can be opened and closed without force: the NMR-CUFF.

Sub types

Journal Article

Ausgabe der Zeitschrift

208

Data source: Europe PubMed Central

Abstract

Portable equipment for nuclear magnetic resonance (NMR) is becoming increasingly attractive for use in a variety of applications. One of the main scientific challenges in making NMR portable is the design of light-weight magnets that possess a strong and homogeneous field. Existing NMR magnets can provide such magnetic fields, but only for small samples or in small regions, or are rather heavy. Here we show a simple yet elegant concept for a Halbach-type permanent magnet ring, which can be opened and closed with minimal mechanical force. An analytical solution for an ideal Halbach magnet shows that the magnetic forces cancel if the structure is opened at an angle of 35.3° relative to its poles. A first prototype weighed only 3.1 kg, and provided a flux density of 0.57 T with a homogeneity better than 200 ppm over a spherical volume of 5mm in diameter without shimming. The force needed to close it was found to be about 20 N. As a demonstration, intact plants were imaged and water (xylem) flow measured. Magnets of this type (NMR-CUFF = Cut-open, Uniform, Force Free) are ideal for portable use and are eminently suited to investigate small or slender objects that are part of a larger or immobile whole, such as branches on a tree, growing fruit on a plant, or non-metallic tubing in industrial installations. This new concept in permanent-magnet design enables the construction of openable, yet strong and homogeneous magnets, which aside from use in NMR or MRI could also be of interest for applications in accelerators, motors, or magnetic bearings.

Date of acceptance

2010

Autoren

Carel W Windt
Helmut Soltner
Dagmar van Dusschoten
Peter Blümler

Autoren-URL

https://www.ncbi.nlm.nih.gov/pubmed/21036637

DOI

10.1016/j.jmr.2010.09.020

eISSN

1096-0856

Ausgabe der Veröffentlichung

1

Zeitschrift

J Magn Reson

Schlüsselwörter

Equipment Design
Equipment Failure Analysis
Magnetic Resonance Spectroscopy
Magnetics
Miniaturization
Stress, Mechanical

Sprache

eng

Country

United States

Paginierung

27 - 33

PII

S1090-7807(10)00299-5

Datum der Veröffentlichung

2011

Status

Published

Datum, an dem der Datensatz öffentlich gemacht wurde

2011

Titel

A portable Halbach magnet that can be opened and closed without force: the NMR-CUFF.

Sub types

Journal Article

Ausgabe der Zeitschrift

208

Data source: PubMed

A portable Halbach magnet that can be opened and closed without force: The NMR-CUFF

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