Hyde James S, Mett Richard R
Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plan Road, Milwaukee, WI 53226.
Department of Physics and Chemistry, Milwaukee School of Engineering, 1025 North Broadway, Milwaukee, WI 53202.
Appl Magn Reson. 2017 Dec;48(11-12):1185-1204. doi: 10.1007/s00723-017-0935-4. Epub 2017 Sep 18.
The dielectric tube resonator (DTR) for EPR spectroscopy is introduced. It is defined as a metallic cylindrical TE 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, or 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 dielectric tube resonator 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 TE 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.
介绍了用于电子顺磁共振光谱学的介质管谐振器（DTR）。它被定义为一个金属圆柱形TE微波腔，其中包含一个以圆柱轴线为中心的介质管。展示了石英、蓝宝石和金红石管在9.5 GHz实现谐振时金属圆柱尺寸的等高线图，该图是壁厚和平均半径的函数。这些等高线图是使用解析方程绘制的，并通过有限元建模得到了验证。它们有两种用途：设计用于9.5 GHz的金属圆柱，其中包含一个易于获得的管，如用于核磁共振的蓝宝石管；或者设计一个定制采购的管，以针对特定样品尺寸限制优化性能。这些图表延伸到介质充满管子的极限情况。然而，在此极限下的结构由于金属壁而不是介质谐振器，并且不辐射。此外，还介绍了均匀场（UF）DTR。展示了从介质管谐振器开始的UF谐振器的发展过程。管子的直径沿腔轴保持不变，圆柱形金属外壳的直径在腔的两端增大，以满足均匀场条件。这种结构相对于先前开发的UF TE谐振器具有优势：谐振器效率参数Λ更高，使用蓝宝石管时整体尺寸方便，并且对于小样品能获得更高质量的数据。DTR和UF DTR结构以连续的方式填补了自由空间和介质谐振器极限之间的空白。
