4D shimming of Halbach Array Magnet System

_Spin Echo Limited是一家多相流量计的原始设备制造商（OEM），用于氢气+天然气混合物的运输，碳捕获应用和常规石油和天然气生产，通过降低含水量和相关（火炬）气体的产生量来优化生产产量和环境性能。__该公司创新的核磁共振（NMR）流量计技术利用低成本的Halbach阵列磁体系统来创建适合进行NMR测量的电磁真空。为了实现所需的磁场（0.12T强度和<1000 ppm的磁场误差），有必要对Halbach阵列磁体进行匀场。匀场是在磁场源和测量平面之间添加少量磁性材料以有效调节磁场的过程。在与ASTUTE的合作中，该项目将寻求定义一种新的匀场算法，该算法将改进Spin Echo制造过程中使用的现有匀场能力。改进Halbach阵列磁场的均匀性将提高仪表在精度和制造成本方面的性能。为了实现一种新的匀场算法，项目合作伙伴将使用专门的软件完成数值分析、建模和3D模拟工作，以定义一种新的匀场安排。目前，在自旋回波的生产过程中采用的匀场算法仅考虑2个维度-匀场宽度和匀场相对于磁源的径向位置。本项目将考虑垫片长度和垫片相对于磁源的轴向位置的附加尺寸。__项目合作伙伴认为，这种新的4D匀场算法可以显著提高NMR流量计的精度和可制造性。如果新的4D算法实现低于100 ppm范围的磁场误差，Halbach阵列磁体系统还可以找到新的应用，例如用于医疗保健目的的低成本MRI扫描或作为储能容器。

_Spin Echo Limited is an Original Equipment Manufacturer (OEM) of multi-phase flowmeters for use in the transport of hydrogen + natural gas admixtures, carbon capture applications and in convention Oil & Gas production as a means to optimize production yield and environmental performance by lowering the amount of water cut and associated (flare) gas produced.__The company's innovative Nuclear Magnetic Resonance (NMR) flowmeter technology utilizes a low-cost Halbach array magnet system to create an electromagnetic vacuum suitable for NMR measurements to be taken. In order to achieve the required magnetic field (0.12T strength and <1000ppm field error), it is necessary to shim the Halbach array magnet. Shimming is the process of adding small amounts of magnetic material between the magnetic field source and measurement plane to effectively tune the field.__In partnership with ASTUTE, this project will seek to define a new shimming algorithm that will improve upon the existing shimming capabilities employed in Spin Echo's manufacturing process. Improvements to the homogeneity in the magnetic field of the Halbach array will improve meter performance in terms of accuracy and cost to manufacture.__To realise a new shimming algorithm, the project partners will complete numerical analysis, modelling and 3D simulation work using specialized software to define a new arrangement of shims . At present, the shimming algorithm employed in Spin Echo's production process only considers 2 dimensions - shim width and radial location of the shim relative to the magnetic source. This project will consider the addition dimensions of shim length and axial location of the shim relative to the magnetic source.__The project partners believe that this new 4D shim algorithm could lead to significant improvements in the accuracy and manufacturability of the NMR flowmeter. Should the new 4D algorithm achieve field error in the sub 100ppm range, the Halbach array magnet system could also find new applications such as a low-cost MRI scanning for health care purposes or as an energy storage vessel._