95GHZ CW ESR SPECTROMETER DEVELOPMENT

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 在我们广泛开发95 GHz高功率脉冲工作的同时，我们还利用了95 GHz光谱仪的连续波功能。 连续波操作的最佳操作参数，特别是在谐振器耦合和品质因数的选择，是充分不同的脉冲工作，我们已经纳入了显着的补充设备的光谱仪时，在连续波模式操作。然而，与此同时，我们希望确保从脉冲到连续操作的快速转换是可行的。 在完成了大量的设计和开发工作后，我们实现了这一设计目标。 执行连续波工作所需的其他设备包括：磁场调制放大器，光谱仪同相和正交通道上的锁定检测器，用于从磁场调制中对连续波频谱进行去卷积，以及专门设计的场调制线圈，用于减少这项工作所需的高磁场中的颤噪效应。 重要的开发工作也使我们能够建立有用的，快速的调谐协议的基础上相移的毫米波入射到谐振器上，以区分不必要的桥内反射谐振器的响应。 我们正在探索如何在我们的170/240 GHz桥接器上实现这些改进的调谐技术。 最近的工作也集中在改进温度控制和实现单晶旋转能力作为ACERT中心的多频能力的一部分。 我们的设置的另一个优点是，从脉冲到连续操作的转换可能会受到影响，而不会干扰样品，这为研究人员提供了非常有用的灵活性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In parallel with our extensive development of high power pulse work at 95GHz, we have also exploited the cw capabilities of our 95GHz spectrometer. The optimum operating parameters for cw operation, particularly in the choice of the resonator coupling and quality factor, are sufficiently different from pulsed work that we have incorporated significant supplemental equipment into the spectrometer when operating in cw mode. At the same time, however, we wanted to ensure that rapid conversion from pulse to cw operation would be feasible. After a significant amount of design and development work was completed, we achieved this design goal. Additional equipment necessary for performing cw work includes: a magnetic field modulation amplifier, lock-in detectors on the spectrometer in-phase and quadrature channels to deconvolve the cw spectrum from the magnetic field modulation, and a specially designed field modulation coil designed to reduce microphonics in the high magnetic fields necessary for this work. Significant development work has also allowed us to establish useful, rapid tuning protocols based on phase shifting the millimeter waves incident on the resonator to distinguish unwanted intra-bridge reflections from the resonator response. We are exploring ways to implement these improved tuning techniques on our 170/240GHz bridge. Recent work has also focused on improved temperature control and implementing single crystal rotation capability as part of the multifrequency capability of the ACERT center. Another advantage of our setup is that the conversion from pulse to cw operation may be affected without disturbing the sample, which provides a very useful degree of flexibility to the investigator.