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

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

9909598 Mukasa This 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. ***