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@ARTICLE{Windt:11078,
author = {Windt, C. W. and Soltner, H. and van Dusschoten, D. and
Blümler, P.},
title = {{A} portable {H}albach magnet that can be opened and closed
without force: {T}he {NMR}-{CUFF}},
journal = {Journal of magnetic resonance},
volume = {208},
issn = {1090-7807},
address = {Amsterdam [u.a.]},
publisher = {Elsevier},
reportid = {PreJuSER-11078},
year = {2011},
note = {Record converted from VDB: 12.11.2012},
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.},
keywords = {Equipment Design / Equipment Failure Analysis / Magnetic
Resonance Spectroscopy: instrumentation / Magnetics:
instrumentation / Miniaturization / Stress, Mechanical / J
(WoSType)},
cin = {IBG-2},
ddc = {550},
cid = {I:(DE-Juel1)IBG-2-20101118},
pnm = {Terrestrische Umwelt},
pid = {G:(DE-Juel1)FUEK407},
shelfmark = {Biochemical Research Methods / Physics, Atomic, Molecular
$\&$ Chemical / Spectroscopy},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:21036637},
UT = {WOS:000286774300004},
doi = {10.1016/j.jmr.2010.09.020},
url = {https://juser.fz-juelich.de/record/11078},
}