We show that the temporal magnetic field distortion generated by the Cold Head operation can be removed and high quality Solid-State Magic Angle Spinning NMR results can be obtained with a cryogen-free magnet. The compact design of the cryogen-free magnets allows for the probe to be inserted either from the bottom (as in most NMR systems) or, more conveniently, from the top. The magnetic field settling time can be made as short as an hour after a field ramp. Therefore, a single cryogen-free magnet can be used at different fixed fields. The magnetic field can be changed every day without compromising the measurement resolution.

中文翻译：

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具有液态 NMR 势能的无制冷剂 400 MHz (9.4 T) 固态 MAS NMR 系统

我们表明，可以消除由冷头操作产生的时间磁场畸变，并且可以使用无致冷剂磁体获得高质量的固态魔角自旋核磁共振结果。无制冷剂磁铁的紧凑设计允许从底部插入探头（如在大多数 NMR 系统中），或者更方便的是从顶部插入。磁场稳定时间可以缩短到磁场斜坡后的一个小时。因此，单个无致冷剂磁体可用于不同的固定场。磁场可以每天改变，而不会影响测量分辨率。