ESR MICROSCOPE MKII HIGH VOLTAGE PREREGULATOR

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 Acert Ku波段脉冲ESR显微镜目前的分辨率为~0.7x0.75x0.75？m，使用高达425伏的峰值梯度线圈驱动电压。为了观察生物ESRM信号，我们需要一个明显更短的梯度脉冲间隔，这意味着更高的电压和更小的驱动器网络储能电容值。我们的目标是在峰值梯度接近100T/m的情况下，产生高达600伏的最小峰值线圈驱动电压和800 ns或更小的脉冲宽度。实现显著降低脉冲宽度的策略是通过安装800伏MOSFET输出设备来升级梯度驱动器子系统，以取代以前的600伏设备，并用大幅升级的版本取代用于预充电驱动器通道高压电容器的现有预调压系统。已经对梯度驱动器子系统进行了修改，以实现更高的输出电压能力。然而，驱动它的预调制器只能提供450伏的电压，尽管峰值电流输出约为11安培。我们将在几周内用MKII版本取代预调制器，提供至少800伏、10安培能力的两个通道。通过这种组合的梯度驱动系统，我们预计将使用T2更短的自旋探针，例如适合于生物成像的氮氧化物。

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. At its present level of resolution, ~0.7x0.75x0.75¿m, the ACERT Ku-band pulse ESR microscope utilizes peak gradient coil drive voltages of up to 425 volts. For observation of biological ESRM signals, we desire a significantly shorter gradient pulse interval, implying higher voltages and smaller values of driver network energy storage capacitance. Our goals are generation of peak coil drive voltages up to 600 volts, minimum, and pulse widths of 800ns or less at peak gradients approaching 100 T/m. The strategy for accomplishing significantly reduced pulse widths is to upgrade the gradient driver subsystem by installation of 800 volt MOSFET output devices in place of the prior 600 volt devices, and to replace the existing preregulator system that is employed to precharge the driver channel high-voltage capacitors with a substantially upgraded version. Modifications of the gradient driver subsystem to achieve higher output voltage capability have already been made. However, the preregulator driving it is capable of only 450 volts, although ca 11 amperes peak current output. We will replace the preregulator within a few weeks with a MKII version providing two channels of at least 800 volt, 10 amperes capability. With this combined gradient driver system, we anticipate utilizing spin probes with shorter T2, e.g. nitroxides, that are appropriate for biological imaging.