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

9909598-本提案请求国家科学基金会提供资金，以升级和翻新密歇根大学自1987年以来一直在使用的VG扇区热电离质谱仪之一。作为地质科学系两个放射性同位素研究小组十多年来的主力，这款质谱仪具有“多1”收集器块，带有六个旧设计、寿命短的手动移动的法拉第杯子。由于其老化和吞吐量较高，法拉第探测器遭受了一些损坏，导致了增益和峰值形状的下降。这种磨损的最终结果是锶和钕同位素比值测量的精确度和重复性较差。此外，仪器中的电子元件已经老化，并开始造成破坏性停机。其中最关键的是Solatron数字电压表(DVM)，众所周知，它随着年龄的增长而变得喜怒无常，一直是许多其他同位素实验室的挫折之源。Solatron DVM已经不再生产，因此找到足够的部件来修复它们已经成为一个问题。为了延长质谱计的使用寿命，法拉第探测器、DALY探测器和DVM探测器需要更换为在稳定性、灵敏度和耐用性方面具有优越性能的更现代的同类探测器。还需要适度的资金来为这台质谱仪购买灯丝放气器。如提案所述，质谱仪及其外围设备对几名教职员工、博士后研究员和研究生的研究至关重要。

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.***