DEVELOPMENT OF RECEIVER PROTECTOR FOR PULSED ESR

脉冲 ESR 接收器保护器的开发

• 批准号: 8363938
• 负责人: Jack H Freed
• 金额: $ 1.05万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363938
• 关键词: Development; Electromagnetics; Frequencies; Funding; Grant; Home environment; National Center for Research Resources; Performance; Physiologic pulse; Principal Investigator; Recovery; Research; Research Infrastructure; Resources; Sampling Studies; Source; Specific qualifier value; Speed; Staging; Technology; Testing; Time; United States National Institutes of Health; Work; base; cold temperature; cost; design; ferrite; nanosecond; operation

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. The design work on the high-power stage of a receiver protector switch for 35 GHz is completed. We are integrating the ferrite switch with a fast, low-power, pin-diode switch that we recently acquired. We successfully tested a ferrite-based latching circulator intended for 35 GHz work. It is controlled by a home-built, fast, pulsed current driver. The switching speed is better than 20 ns, which is adequate for its use in FT-ESR. The repetition rate for this switch is 5 kHz, but we have not attempted to increase it further due to lack of a spare switch. The remaining work also includes minimizing electromagnetic interference from intense current pulses in its normal mode of operation as a part of the 35 GHz spectrometer. We routinely use 200 W limiters to handle 1-1.5 kW pulses of nanosecond duration for 8-18 GHz frequency range. For operating frequencies up to 18 GHz at higher peak power we recently procured passive receiver protectors rated to 1 kW for 1 ?s pulses. This would be adequate for nanosecond pulses of higher intensity. Their recovery time of 50 ns is adequate for low-temperature DQC work, but may be problematic for 2D-ELDOR for which dead-time should be under 30 ns. This would require a further effort to procure 20 ns ferrite switches and combine them with low-power diode limiters in order to achieve dead-time less than 25 ns. Ferrite switches for X and Ku bands with switching time under 20 ns are not available as standard products. What can be found is specified for larger switching energy than the 35 GHz switch, therefore we plan to obtain samples and study their switching performance.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 在35 GHz的接收器保护器开关的高功率阶段的设计工作已完成。我们正在使用最近获得的快速，低功率，销二极管开关集成了铁氧体开关。我们成功地测试了一个用于35 GHz工作的基于铁氧体的闩锁循环器。它由自制，快速，脉冲的当前驾驶员控制。开关速度大于20 ns，这足以在FT-ESR中使用。此开关的重复率为5 kHz，但由于缺乏备用开关，我们没有尝试进一步增加它。其余的工作还包括最大程度地减少来自强烈的电流脉冲以正常运行方式的电磁干扰，这是35 GHz光谱仪的一部分。 我们通常使用200 W限制器来处理8-18 GHz频率范围的纳秒持续时间的1-1.5 kW脉冲。对于高峰值功率高达18 GHz的运行频率，我们最近在1 kW中以1 kW的速度购买了1 kW的无源接收器保护器。 这足以适用于较高强度的纳秒脉冲。 它们的恢复时间为50 ns是足够的低温DQC工作的，但对于2D级别的死亡时间可能是有问题的，该时间的停留时间应低于30 ns。 这将需要进一步的努力来采购20 ns铁氧体开关，并将它们与低功率二极管限制器结合在一起，以使其达到小于25 ns的死时间。 X和KU频段的铁氧体开关在20 ns以下的开关时间不可用，作为标准产品。 与35 GHz开关相比，可以为更大的开关能量指定发现的内容，因此我们计划获取样品并研究其开关性能。