Radiogenic isotopic techniques require use of an ultra-clean chemistry laboratory for isotope-dilution chemistry and a mass spectrometer for analyzing the chemical results. The Radiogenic Isotope laboratory has the following equipment:
VG-MM54E is a fully-automated, isotope-ratio thermal ionization mass spectrometer (TIMS). It is equipped with a 16-sample turret, which increases sample throughput because of the ability to load and establish high vacuum for analyzing multiple samples at the same time. A photomultiplier system enables measurement of ion beams of <10-16 amperes. The externally adjustable collector slit allows the user to adjust the resolution without needing to break vacuum. It is used primarily to analyze lead, uranium and thorium isotopes for U-series geochronology, U-Th-Pb geochronology, and Pb- and U-isotopic tracer studies.
VG-MM54R is nearly identical to the VG-MM54E. It is primarily used to analyze neodymium, samarium, strontium, rubidium, lead and uranium isotopes for geochronology and tracer studies.
VG-MM54 Sector is a fully-automated isotope-ratio TIMS. It is equipped with a 20-sample turret, a pulse-counting photomultiplier and seven Faraday collectors, six of which are adjustable. Multiple collectors increase the throughput and improve quality of the data. Movable collectors allow measurement of any set of isotopes, from lighter elements such as calcium, to higher elements such as uranium, on the same instrument with only a small amount of effort. It is primarily used for U-Th-Pb isotopic analyses for age determinations, high precision (+/-0.00001) Sr-isotopic composition analyses for age determinations, and studies using radiogenic isotopes of Sr, Pb, U and Th as tracers of geologic processes.
Radiogenic Isotope Laboratory Introduction
Thermal Ionization Mass Spectrometry
U.S. Department of the Interior | U.S. Geological Survey
URL: http://esp.cr.usgs.gov/info/isotope_geochron_lab/equipment.html
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Page Last Modified: Tue 14-Feb-2006 13:01:00 MST
