FABRY PEROT RESONATOR DEVELOPMENT FOR HIGH FREQUENCY ESR

用于高频 ESR 的法布里珀罗谐振器开发

• 批准号: 7723890
• 负责人: KEITH A EARLE
• 金额: $ 0.71万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7723890
• 关键词: Area; Biological; Cells; Computer Retrieval of Information on Scientific Projects Database; Coupling; Development; Elements; Frequencies; Funding; Grant; Head; Housing; Institution; Life; Membrane; Platelet Factor 4; Positioning Attribute; Research; Research Personnel; Resources; Sampling; Scanning; Solutions; Source; Spin Labels; Structure; Techniques; Technology; Temperature; Time; United States National Institutes of Health; Work; aqueous; data acquisition; design; magnetic field; microwave electromagnetic radiation; millimeter; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. There is a need in high-field/high-frequency-ESR (HFHF-ESR) for resonant structures that maximize the available microwave magnetic field, B1 at the sample since the available power from most millimeter wave sources, is very limited. Recent developments in source technology, however, have allowed us to increase the available power at the resonator by a factor of 4 at 170GHz, corresponding to a doubling of the available B1 at that frequency, and a factor of 10 at 240GHz, corresponding to a trebling of the available B1 at that frequency. Given that the data acquisition time is inversely proportional to the square of available B1, this is extremely significant for samples with finite lifetimes, such as spin-labeled live cells. For biological samples there is also a need for resonant structures and sample holders that minimize the dielectric losses inherent in aqueous samples and exploit suitable geometries for orientation dependent studies of macroscopically aligned membrane samples. We have developed an array of solutions for these problems in applications at 95, 170 and 250GHz. Recent work has focused on developing resonators with variable coupling for optimum sensitivity, and good temperature control for quantitative temperature scans. Progress along these lines has been helped by the development of in-house fabrication techniques for the partially reflecting inductive meshes that we use in semi-confocal Fabry-P¿rot (FP) resonators at HFHF-ESR frequencies. In particular, the development of a coupling mesh with continuously variable reflectivity has allowed us to critically couple the resonator to a variety of samples, making the optimum use of the available millimeter wave power. Although development work in these areas has been focused primarily on our 95GHz spectrometer, the technology is applicable to all of our HFHF-ESR spectrometers. We have also incorporated those elements of our aqueous sample holder technology facilitating sample positioning within the FP resonator developed at 250GHz into the 95GHz FP resonators we use for achieving the optimum S/N. We have also recently developed flexible probe-head designs that allow our FP resonators to be operated in the induction or reflection mode, depending on the needs of the experiment.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 在高场/高频ESR（HFHF-ESR）中需要使样品处的可用微波磁场B1最大化的谐振结构，因为来自大多数毫米波源的可用功率非常有限。然而，源技术的最新发展使我们能够在170 GHz处将谐振器处的可用功率增加4倍，对应于该频率处的可用B1的两倍，并且在240 GHz处增加10倍，对应于该频率处的可用B1的三倍。 鉴于数据采集时间与可用B1的平方成反比，这对于具有有限寿命的样品（例如自旋标记的活细胞）非常重要。 对于生物样品，还需要谐振结构和样品保持器，其使含水样品中固有的介电损耗最小化，并利用合适的几何形状用于宏观对齐的膜样品的取向依赖性研究。 我们已经开发了一系列解决方案，在95，170和250 GHz的应用中解决这些问题。 最近的工作集中在开发具有可变耦合的谐振器以获得最佳灵敏度，以及用于定量温度扫描的良好温度控制。 沿着这些路线的进展已经帮助了内部制造技术的发展，我们在半共焦法布里-珀罗（FP）谐振器中使用的部分反射电感网格在HFHF-ESR频率。 特别是，连续可变反射率的耦合网的发展，使我们能够严格耦合谐振器的各种样品，使可用的毫米波功率的最佳利用。 虽然这些领域的开发工作主要集中在我们的95 GHz光谱仪上，但该技术适用于我们所有的HFHF-ESR光谱仪。 我们还将我们的水性样品保持器技术的这些元素整合到我们用于实现最佳S/N的95 GHz FP谐振器中，以便于在250 GHz开发的FP谐振器内定位样品。 我们最近还开发了灵活的探针头设计，使我们的FP谐振器可以根据实验的需要在感应或反射模式下工作。