A dual-core NMR system for field-cycling singlet assisted diffusion NMR.
A dual-core NMR system for field-cycling singlet assisted diffusion NMR.
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DOI：
10.3389/fchem.2023.1229586
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发表时间：
2023
影响因子：
5.5
通讯作者：
中科院分区：
文献类型：
--
作者：
长寿命的单重态自旋顺序提供了将自旋记忆扩展一个数量级以上的可能性。除其他应用外，这种增强功能还可用于协助多孔介质中的 NMR 扩散实验，其中单线态自旋顺序的延长寿命可用于获取有关介质结构特征以及吸入相动力学的信息。除了提供探索几分钟数量级的较长扩散时间的可能性（例如，在具有互连孔隙的结构中提供前所未有的弯曲度）之外，单线态秩序还具有重要的优势，即不受磁化率不均匀性产生的内部场梯度的影响。然而，这些不均匀性导致高磁场中 T2 衰变常数非常短，这首先阻碍了获得单重态序。为了克服这一困难并在多孔介质扩散实验中利用单线态序，我们开发了一种双核系统，具有低磁场中的射频和三轴脉冲场梯度设施，用于制备和操作单线态序，以及在高磁场中用于极化和检测的探针。该系统在场循环中运行，可用于各种 NMR 实验，包括扩散张量成像（单线辅助和非单线辅助）。在本文中，我们介绍并讨论了新硬件及其校准，并通过各种示例展示了其功能。
Long-lived singlet spin order offers the possibility to extend the spin memory by more than an order of magnitude. This enhancement can be used, among other applications, to assist NMR diffusion experiments in porous media where the extended lifetime of singlet spin order can be used to gain information about structural features of the medium as well as the dynamics of the imbibed phase. Other than offering the possibility to explore longer diffusion times of the order of many minutes that, for example, gives unprecedented access to tortuosity in structures with interconnected pores, singlet order has the important advantage to be immune to the internal field gradients generated by magnetic susceptibility inhomogeneities. These inhomogeneities, however, are responsible for very short T2 decay constants in high magnetic field and this precludes access to the singlet order in the first instance. To overcome this difficulty and take advantage of singlet order in diffusion experiments in porous media, we have here developed a dual-core system with radiofrequency and 3-axis pulsed field gradients facilities in low magnetic field, for preparation and manipulation of singlet order and a probe, in high magnetic field, for polarisation and detection. The system operates in field-cycling and can be used for a variety of NMR experiments including diffusion tensor imaging (both singlet assisted and not). In this paper we present and discuss the new hardware and its calibration, and demonstrate its capabilities through a variety of examples.
影响因子：
3.3
作者：
Cartlidge, Topaz A. A.;Robertson, Thomas B. R.;Utz, Marcel;Pileio, Giuseppe
通讯作者：
Pileio, Giuseppe