Low Noise Coupling and Signal Detection for EPR Spectroscopy

由于缺乏工程设计数据，在材料科学、化学、物理、生物和医学等领域的EPR研究中，有希望的新型谐振结构和现代微波技术的应用受到限制。PI建议测试我们对电感耦合、并联电容耦合和串联电容耦合理论结果的定量预测。我们将探讨耦合对尺寸和电气参数的敏感性。最好的设计将用于连续波和脉冲S波段和X波段光谱仪。主要重点将放在标准圆柱管和各种介电常数的溶剂中的样品的更换、返回和变温操作的便利性上。将建造各种设备：一种混合微波EPR电桥，它将比目前的电桥更灵敏、更具成本效益。用于S波段工作的电子可调谐LGR将改善谐振器/匹配网络的可调性。一种系统，其中前置放大器与谐振器一起冷却，以利用在低温下可能产生的低噪声。许多研究小组迫切需要从拟议工作中获得的设计指导。这一结果将增强美国光谱测量的竞争力。

The application of promising new resonant structures and modern microwave technology to EPR studies of problems in materials science, chemistry, physics, biology, and medicine, is limited by the lack of engineering design data. The PI's propose to test the quantitative predictions of our theoretical results for inductive coupling, parallel capacitive coupling, and series capacitive coupling. Sensitivity of coupling to dimensional and electrical parameters will be explored. The best designs will be implemented for CW and pulsed S-band and X- band spectrometers. Primary focus will be on ease of sample change, returning, and variable temperature operation for samples contained in standard cylindrical tubes and in solvents of various dielectric constants. A variety of equipment will be built: A hybrid microwave EPR bridge that will be more sensitive and cost-effective than present bridges. An electronically tunable LGR for S-band operation that will improve tunability of the resonator/matching network. A system in which the preamplifier is cooled along with the resonator to take advantage of the low noise possible at cryogenic temperature. Design guidance that will come from the proposed work is urgently needed by many research groups. The results will enhance the competitiveness of American spectroscopic measurements.