SERVICE UPGRADE OF E 4 SPECTROMETER SYSTEM

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。 作为ACERT长期服务承诺的一部分，ACERT的工作人员进行了工程分析和升级咨询，以改善现有的CW ESR仪器，例如属于ACERT中心的仪器，以及由Gerald Feigenson博士领导的康奈尔大学独立研究小组的仪器。 审查的工具是过时的Varian c.w. ESR光谱仪系统（E-12、E-4）显示S/N和AFC限制，对正在进行的成像工作和弱样品光谱研究产生不利影响。 我们已经设计了一个简单的前端（基带）接收器的重新设计，这将提高信号检测灵敏度，因此，这些光谱仪的实用性。 对于c.w.在成像工作中，已经实施了场稳定的新方法来增强现有AFC系统的稳定性。 这些升级工作与我们的主要服务角色密切相关，即协助ESR研究人员在他们自己的实验室中开发所需的仪器，以执行我们已经开发并正在完善的一些独特实验。 预计我们已经创建并正在持续开发的性能升级将作为一种普遍有用和适用的升级改造，用于仍在许多实验室中运行的一代较旧的CW光谱仪。

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. As part of ACERT's standing service commitment, ACERT staff members have undertaken engineering analysis and upgrade consultation to improve an existing CW ESR instruments such as those belonging to the ACERT center and also to a separate Cornell research group headed by Dr. Gerald Feigenson. The instruments under review are outdated Varian c.w. ESR spectrometer systems (E-12, E-4) which exhibit S/N and AFC limitations adversely affecting ongoing imaging work and the study of weak-sample spectra. We have engineered a straightforward front-end (base band) receiver redesign which will improve the signal detection sensitivity and, hence, the utility of these spectrometers. For c.w. imaging work, novel methods of field stabilization have been implemented to augment the existing AFC system stability. These upgrade efforts are strongly related to our major service role of assisting ESR researchers to develop, in their own laboratories, the instrumentation needed to perform some of the unique experiments that we have developed and are currently refining. It is anticipated that the performance upgrades that we have created and which are in continuing development will serve as a generally useful and applicable upgrade retrofit for a generation of older CW spectrometers still operational in many laboratories.