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首页> 外文期刊>Journal of magnetic resonance >Operation of a 500 MHz high temperature superconducting NMR: Towards an NMR spectrometer operating beyond 1 GHz
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Operation of a 500 MHz high temperature superconducting NMR: Towards an NMR spectrometer operating beyond 1 GHz

机译：500 MHz高温超导NMR的操作：运行1 GHz以上的NMR光谱仪

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摘要

We have begun a project to develop an NMR spectrometer that operates at frequencies beyond 1 GHz (magnetic field strength in excess of 23.5 T) using a high temperature superconductor (HTS) innermost coil. As the first step, we developed a 500 MHz NMR with a Bi-2223 HTS innermost coil, which was operated in external current mode. The temporal magnetic field change of the NMR magnet after the coil charge was dominated by (i) the field fluctuation due to a DC power supply and (ii) relaxation in the screening current in the HTS tape conductor; effect (i) was stabilized by the H-2 field-frequency lock system, while effect (ii) decreased with time due to relaxation of the screening current induced in the HTS coil and reached 10(-8)(0.01 ppm)/h on the 20th day after the coil charge, which was as small as the persistent current mode of the NMR magnet. The 1D H-1 NMR spectra obtained by the 500 MHz LTS/HTS magnet were nearly equivalent to those obtained by the LTS NMR magnet. The 2D-NOESY, 3D-HNCO and 3D-HNCACB spectra were achieved for ubiquitin by the 500 MHz LTS/HTS magnet; their quality was closely equivalent to that achieved by a conventional LTS NMR. Based on the results of numerical simulation, the effects of screening current-induced magnetic field changes are predicted to be harmless for the 1.03 GHz NMR magnet system.
机译：我们已经开始一个项目，该项目使用最里面的高温超导体（HTS）开发一个NMR光谱仪，该光谱仪的工作频率超过1 GHz（磁场强度超过23.5 T）。第一步，我们开发了Bi-2223 HTS最内层线圈的500 MHz NMR，该线圈在外部电流模式下运行。线圈电荷后NMR磁体的瞬时磁场变化主要受（i）由于直流电源引起的磁场波动和（ii）HTS带状导体中屏蔽电流的松弛; H-2场频锁定系统稳定了效应（i），而由于HTS线圈中感应的屏蔽电流的松弛，效应（ii）随着时间的推移而降低，并达到10（-8）（0.01 ppm）/ h在线圈充电后的第20天，其大小与NMR磁体的持续电流模式一样小。通过500 MHz LTS / HTS磁体获得的1D H-1 NMR谱图与通过LTS NMR磁体获得的1D H-1 NMR谱图几乎相等。通过500 MHz LTS / HTS磁体获得了遍在蛋白的2D-NOESY，3D-HNCO和3D-HNCACB光谱;它们的质量与传统的LTS NMR相当。基于数值模拟的结果，屏蔽电流感应磁场变化的影响预计对于1.03 GHz NMR磁体系统是无害的。

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