Sidabras Jason W, Mett Richard R, Hyde James S
Medical College of Wisconsin, Department of Biophysics, Milwaukee, WI 53226, USA.
Medical College of Wisconsin, Department of Biophysics, Milwaukee, WI 53226, USA; Milwaukee School of Engineering, Department of Physics and Chemistry, Milwaukee, WI 53202, USA.
J Magn Reson. 2017 Apr;277:45-51. doi: 10.1016/j.jmr.2017.02.009. Epub 2017 Feb 14.
This paper builds on the work of Mett and Hyde (2003) and Sidabras et al. (2005) where multiple flat aqueous sample cells placed perpendicular to electric fields in microwave cavities were used to reduce the RF losses and increase the EPR signal. In this work, we present three novel sample holders for loop-gap resonators (LGRs) and cylindrical cavity geometries. Two sample holders have been commissioned and built by polytetrafluoroethylene (PTFE) extrusion techniques: a 1mm O.D. capillary with a septum down the middle, named DoubleDee, and a 3.5mm O.D. star shaped sample holder, named AquaStar. Simulations and experimental results at X-band show that the EPR signal intensity increases by factors of 1.43 and 3.87 in the DoubleDee and AquaStar respectively, over the current TPX 0.9mm O.D. sample tube in a two-loop-one-gap LGR. Finally, combining the insight gained from the constructed sample holders and finite-element solutions, a third multi-lumen sample holder for a cylindrical TE cavity is optimized, named AquaSun, where simulations show an EPR signal intensity increase by a factor of 8.2 over a standard 1mm capillary.
本文基于梅特和海德（2003年）以及西达布拉斯等人（2005年）的工作，他们在微波腔中使用多个垂直于电场放置的扁平水性样品池来降低射频损耗并增强电子顺磁共振（EPR）信号。在这项工作中，我们展示了三种用于环形间隙谐振器（LGR）和圆柱形腔几何结构的新型样品架。其中两种样品架是通过聚四氟乙烯（PTFE）挤压技术制作并投入使用的：一种是外径为1mm的毛细管，中间有一个隔膜，名为双D型；另一种是外径为3.5mm的星形样品架，名为水之星。在X波段的模拟和实验结果表明，在双环单间隙LGR中，与当前外径为0.9mm的TPX样品管相比，双D型和水之星的EPR信号强度分别提高了1.43倍和3.87倍。最后，结合从已制作的样品架和有限元解决方案中获得的见解，对用于圆柱形TE腔的第三种多腔样品架进行了优化，名为水太阳，模拟结果表明其EPR信号强度比标准1mm毛细管提高了8.2倍。
