A simple, small and low cost permanent magnet design to produce homogeneous magnetic fields
A simple, small and low cost permanent magnet design to produce homogeneous magnetic fields
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DOI：
10.1016/j.jmr.2008.02.011
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发表时间：
2008-05-01
影响因子：
2.2
通讯作者：
Volke, F.
中科院分区：
文献类型：
--
作者：
Manz, B.;Benecke, M.;Volke, F.
提出了一种基于新型永磁体布置的新型便携式袖珍核磁共振探头。它基于Halbach型磁体设计，该设计通过使用圆柱形棒和环形磁体来模拟球形偶极子的场。磁体系统仅由三个单独的磁体组成，大多数磁场计算和优化都可以通过分析进行。一个原型系统已建成使用一套小型的，现成的商用永磁体。在1T的场强下，可以获得50ppm的半高宽的质子线宽.计算表明，使用定制尺寸的永磁体，可以在高达1 mm的样品体积上实现小于1 ppm的线宽（3），这在理论上可以在质量有限的样品上实现化学位移分辨质子光谱。但即使实现了50 ppm的线宽，这也是一种有用的便携式传感器，适用于分子流动性受限的少量液体样品，如凝胶、聚合物或高粘度液体。(C)2008年爱思唯尔公司All rights reserved.
A new portable, pocket-size NMR probe based on a novel permanent magnet arrangement is presented. It is based on a Halbach-type magnet design which mimics the field of a spherical dipole by using cylindrical bar and ring magnets. The magnet system is made up of only three individual magnets, and most field calculations and optimisations can be performed analytically. A prototype system has been built using a set of small, off the shelf commercially available permanent magnets. Proton linewidths of 50 ppm FWHM could be achieved at a field strength of 1 T. Calculations show that with custom-sized permanent magnets, linewidths of less than 1 ppm can be achieved over sample volumes of up to 1 mm(3), which would in theory enable chemical shift resolved proton spectroscopy on mass-limited samples. But even with the achieved linewidth of 50 ppm, this can be a useful portable sensor for small amounts of liquid samples with restricted molecular mobility, like gels, polymers or high viscosity liquids. (C) 2008 Elsevier Inc. All rights reserved.