ESR MICROSCOPE FIELD/FREQUENCY LOCK UPGRADE

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。 目前用于16 Ghz显微成像工作的老化瓦里安磁场调节系统的稳定性经常出现困难，这使我们探索实现足够B 0稳定性的临时方法。 一个成功的方法，我们已经实施了一个临时的基础上，目前的ESR显微成像研究，等待安装一个新的磁铁电源和调节系统，今年晚些时候，是一个字段/频率衍生的调节补丁的基础上现有的字段/频率锁定（FFL）系统。使用FFL，我们能够在给定的ESR显微镜实验的持续时间内保持5 ppm的相对场稳定性，这足以满足我们的迫切需要。这次中期升级的一个重要方面是，我们在添加当前FFL贴片方面获得的经验有助于深入了解混合（霍尔/FFL）磁场调节驱动器的设计要求和实际解决方案，该驱动器将于2008年秋季与新的开关模式磁体电源一起安装。

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. Recurrent difficulties with stability of the aging Varian Fieldial magnetic field regulation system presently employed for 16Ghz microimaging work has led us to explore interim methods for achieving adequate B0 stability. A successful method we have implemented on an interim basis for current ESR microimaging studies, pending installation of a new magnet power source and regulation system later this year, is a field/frequency-derived regulation patch based on an existing field/frequency lock (FFL) system. Using the FFL, we are able to maintain relative field stability on the order of 5ppm over the duration of a given ESR microscopy experiment, which is adequate for our immediate needs. An important aspect of this interim upgrade is that our experience gained in adding the current FFL patch yields helpful insight into the design requirements and practical solution for a hybrid (Hall/FFL) magnetic field regulation driver that will be installed with the new switchmode magnet power source in fall, 2008.