Rutile dielectric loop-gap resonator for X-band EPR spectroscopy of small aqueous samples
Rutile dielectric loop-gap resonator for X-band EPR spectroscopy of small aqueous samples
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DOI：
10.1016/j.jmr.2019.106585
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发表时间：
2019-10-01
影响因子：
2.2
通讯作者：
Hyde, James S.
中科院分区：
文献类型：
--
作者：
Mett, Richard R.;Sidabras, Jason W.;Hyde, James S.
含有介质的金属微波谐振器的性能取决于金属和介质表面之间的分离，这会影响射频电流、逝去波和极化电荷。这个问题以前已经在X波段TE011圆柱形腔谐振器中讨论过，该谐振器包含一个轴向介质管(Hyde和Mett，2017)。在这里，考虑了插入X波段环隙谐振器(LGR)的金红石型介质短管，称为介质LGR(DLGR)。发展了理论，并给出了实验结果。研究发现，中心样品环由四个“磁通-回流”环(即，5环-4间隙)包围比3-环-2-间隙构型更可取。对于足够小的样品(小于1亩L)，在恒定的波长(B-1/根P-L)和恒定的入射功率下，相对于LGR，金红石型dLGR是首选的。在X波段EPR中引入LGR技术是定点自旋标记技术的一个重大进步，因为它的样本量小，波长高。这项工作中介绍的金红石型dLGR提供了进一步的扩展，当使用典型的EPR采集时间时，样品可以小到50nL。(C)2019 Elsevier Inc.保留所有权利。
The performance of a metallic microwave resonator that contains a dielectric depends on the separation between metallic and dielectric surfaces, which affects radio frequency currents, evanescent waves, and polarization charges. The problem has previously been discussed for an X-band TE011 cylindrical cavity resonator that contains an axial dielectric tube (Hyde and Mett, 2017). Here, a short rutile dielectric tube inserted into a loop-gap resonator (LGR) at X-band, which is called a dielectric LGR (dLGR), is considered. The theory is developed and experimental results are presented. It was found that a central sample loop surrounded by four "flux-return" loops (i.e., 5-loop-4-gap) is preferable to a 3-loop-2-gap configuration. For sufficiently small samples (less than 1 mu L), a rutile dLGR is preferred relative to an LGR both at constant Lambda (B-1/root P-l) and at constant incident power. Introduction of LGR technology to X-band EPR was a significant advance for site-directed spin labeling because of small sample size and high Lambda. The rutile dLGR introduced in this work offers further extension to samples that can be as small as 50 nL when using typical EPR acquisition times. (C) 2019 Elsevier Inc. All rights reserved.