Upgrading and Refurbishing of the "Multi-1" Mass Spectrometer at the University of Michigan

该提案要求美国国家科学基金会提供资金，用于升级和翻新自1987年以来一直在密歇根大学使用的VG扇区热电离质谱仪之一。这台质谱仪是地质科学系两个放射性成因同位素研究小组十多年来的主力车，它有“Multi-1”收集器，上面有六个老式的、短寿命的法拉第杯，可以手动移动。由于它们的年龄和吞吐量较长，法拉第探测器遭受了一些损坏，导致增益和峰形退化。这种磨损的最终结果是Sr和Nd同位素比值测量的精度和可重复性差。此外，仪器中的电子元件已经老化，并开始造成破坏性的停机时间。其中最关键的是Solatron数字电压表（DVM's），众所周知，随着时间的推移，它会变得喜怒无常，并且已经成为许多其他同位素实验室受挫的根源。Solatron的DVM不再生产，因此找到足够的零件来修理它们已经成为一个问题。为了延长这种质谱仪的使用寿命，法拉第探测器、戴利探测器和DVM探测器需要被更现代的同类设备所取代，这些设备在稳定性、灵敏度和耐用性方面都有更好的表现。还要求适当的资金为这个质谱仪购买一个灯丝外气器。质谱仪及其周边设备对一些教职员工、博士后和研究生的研究至关重要，如提案所述

9909598MukasaThis proposal requests funds from the National Science Foundation to upgrade and refurbish one of the VG Sector thermal ionization mass spectrometers that has been in service at the University of Michigan since 1987. The workhorse of two radiogenic isotope research groups in the Department of Geological Sciences for over a decade, this mass spectrometer has the "Multi-1" collector block with six old-design, short-life Faraday cups that are moved manually. Because of their advanced age and throughput, the Faraday detectors have suffered some damage leading to degradation in gain and peak shape. The net result of this wear and tear is poor precision and reproducibility in the measurements of Sr and Nd isotopic ratios. In addition, electronic components in the instrument have aged and are beginning to impose disruptive downtimes. Most critical of these are the Solatron digital voltmeters (DVM's), which are known to become temperamental with age and have been the source of frustrations in many other isotope labs. Solatron DVM's are no longer manufactured, and therefore finding adequate parts to fix them has become a problem. In order to lengthen the service of this mass spectrometer, the Faraday detectors, the Daly detector and the DVM's need to be replaced by their more modern equivalents, which have superior performance in stability, sensitivity and durability. Modest funds are also requested to purchase a filament outgasser for this mass spectrometer. The mass spectrometer and its periphery equipment are critically important to the research of several faculty members, postdoctoral fellows and graduate students as detailed in the proposal.***