The dielectric tube resonator (DTR) for electron paramagnetic resonance spectroscopy is introduced. It is defined as a metallic cylindrical TE011 microwave cavity that contains a dielectric tube centered on the axis of the cylinder. Contour plots of dimensions of the metallic cylinder to achieve resonance at 9.5 GHz are shown for quartz, sapphire, and rutile tubes as a function of wall thickness and average radius. These contour plots were developed using analytical equations and confirmed by finite-element modeling. They can be used in two ways: design of the metallic cylinder for use at 9.5 GHz that incorporates a readily available tube such as a sapphire tube intended for NMR and design of a custom procured tube for optimized performance for specific sample-size constraints. The charts extend to the limiting condition where the dielectric fills the tube. However, the structure at this limit is not a dielectric resonator due to the metal wall and does not radiate. In addition, the uniform field (UF) DTR is introduced. Development of the UF resonator starting with a DTR is shown. The diameter of the tube remains constant along the cavity axis, and the diameter of the cylindrical metallic enclosure increases at the ends of the cavity to satisfy the uniform field condition. This structure has advantages over the previously developed UF TE011 resonators: higher resonator efficiency parameter Λ, convenient overall size when using sapphire tubes, and higher quality data for small samples. The DTR and UF DTR structures fill the gap between free space and dielectric resonator limits in a continuous manner.

中文翻译：

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通过腔体中的电介质管增强 EPR 均匀场信号


介绍了用于电子顺磁共振波谱的介质管谐振器（DTR）。它被定义为金属圆柱形 TE011 微波腔体，其中包含以圆柱体轴线为中心的介电管。显示了石英、蓝宝石和金红石管在 9.5 GHz 下实现谐振的金属圆柱尺寸的等高线图，作为壁厚和平均半径的函数。这些等值线图是使用解析方程绘制的，并通过有限元建模进行确认。它们可以通过两种方式使用：设计在 9.5 GHz 下使用的金属圆柱体，其中包含现成的管子，例如用于 NMR 的蓝宝石管，以及设计定制采购的管子，以针对特定样本大小限制优化性能。该图表延伸至电介质充满管子的限制条件。然而，由于金属壁的原因，该极限下的结构不是介电谐振器并且不辐射。此外，还引入了均匀场（UF）DTR。显示了从 DTR 开始的 UF 谐振器的开发。管的直径沿腔轴保持恒定，并且圆柱形金属外壳的直径在腔的末端增加以满足均匀场条件。这种结构比之前开发的UF TE011谐振器具有优势：更高的谐振器效率参数Λ、使用蓝宝石管时方便的整体尺寸以及小样品的更高质量的数据。 DTR 和 UF DTR 结构以连续的方式填补了自由空间和介电谐振器极限之间的间隙。