Noble Gas Laboratory

Lab History

Rutgers Noble Gas Laboratory situated in the Department of earth and Planetary Sciences was completed in 2003.  The lab is built around a Mass Analyzer Products MAP 215-50 noble gas mass spectrometer obtained from Princeton University with the closing of Tullis Onstott’s Argon Lab and was moved to Rutgers in 2002. The mass spectrometer, moved to Rutgers in 2002, is especially designed for the measurement of He and Ar, having 90° sector extended-geometry for enhance separation of Ar and He isotopes.  During installation, researchers Brent Turrin and Carl Swisher modified and upgraded the detector housing of the mass spec to accommodate a new Pfeiffer SEV 217 electron multiplier, which is larger and more stable than the model shipped with the mass spec. The pumping system on the mass spectrometer was also updated to accommodate an automated VAT valve, turbomolecular and Vac-ion for improved pumping of residual gases.

The mass spectrometer was connected to a fully automated, in-house designed, micro-extraction system with a total volume ~180 cc.  The extraction system consists of a central hub with an internal ‘getter’ and ‘cold-finger/trap’ that reduces hydrocarbon and water interferences prior to mass spectrometry measurement. The new hub was designed by Turrin and Swisher and manufactured in Rutgers’ Physics machine shop by Master machinist William Schneider, Val Myrnyj, Eric Paduch and Ernie Erskine.  While the getter ‘cracks’ hydrocarbons, the cold finger operates at temperatures of ~90 to 110K collecting water vapor.  The advantage of the internal cold finger is the lack of external icing associated with older external cold fingers designs used in other labs. Because there is no external icing, the time between thawing and freezing the cold-finger/trap reduces down time requiring reactivation intervals to a month or more instead of once a week.

The micro-extraction system (as well as the mass spectrometer) uses automated, air driven, high conductance all metal valves from VAT Inc.  The Noble Gas System is the first to use high conductance valves from VAT Inc. The extraction system was fitted with dual, newly designed sample chambers.  The sample chambers designed by Turrin and Swisher, also manufactured in Physics) present a low cost (~$1800) alternative IR view port to $15,000 commercially available IR view ports. The IR view port has vacuum degassing rates comparable with commercially available IR view port and window materials can easily be replaced or changed if damaged, at a fraction of the cost of an entirely new commercially available viewport.

A New Wave Research Inc. CO2 laser system, designed in cooperation with Rutgers is used to fuse or incrementally heat geologic samples.  The laser system incorporates a 50 watt Coherent CO2 laser, focusing mirrors, 2 mm and 6 mm integrator lenses, a two-color IR oprical pyrometer, and video camera, all mounted on an automated precision X, Y, Z stage to permit sample selection, focusing and image collection. All aspects of the mass spectrometer operation, the extraction and laser systems are automated, controlled using an Apple Computer running OS X, with dual 20 inch monitors, operated with software written by colleague Alan Deino (Berkeley Geochronology Center), specially modified for Rutgers.  The noble gas isotopic data are collected by the mass spec control.

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