Syracuse University Noble Gas Isotopic Research Laboratory

Micromass 5400 Noble Gas Mass Spectrometer and Extraction Line

The laboratory employs a custom furnace system, 25 watt CO2 laser equipped with two-color IR probe, and ultrahigh vacuum extraction line connected to a state-of-the-art Micromass 5400 noble gas mass spectrometer. The 5400 has both faraday cup and ion-counting electron multiplier capabilities. With the axial multiplier, the spectrometer has a mass resolution of >600. We typically run at 100µA trap current for argon analyses with a corresponding sensitity of 1.63 E-4 amps/torr. The ion-counting system has a dead-time of approximately 20 ns and dark count rates are less than 1 cps. The extraction line for the 5400 consists of an all-metal system. Sample outgassing is achieved either by a double vacuum resistance-heated tantalum furnace or CO2 laser beam. The furnace is controlled via a Eurotherm programable controller and thermocouple in contact with the bottom of the crucible and mounted on the outer (low) vacuum side of the furnace. Two SAES ST-707 getters, one hot and one cold, are used for purification of the gas prior to inlet. A Janis high-temperature, closed cycle cryogenic cold trap system will be used for applications involving separation of noble gases. The extraction line is computer controlled using a LabVIEW program and gas handling routines are automated. See below for pictures and detailed diagrams of the extraction line.

Custom, double-vacuum resistance furnace and extraction line. Blank flange on right-hand side connects to laserport bellows.

Captain Kirk enjoys lasing Vulcanic ashes with this 25 watt CO2 laser system, custom built in-house. The laser system is equipped with a two-color IR probe for laser step-heating analyses. The laser table is on wheels and the system can be utilized on the helium extraction line for Pt-encapsulated single grain analyses of apatite.

Custom CO2 laser viewport with Cleartran window.

Now, looky here:

This is a plan view of the extraction line. We are using Swagelok (Nupro) 6BG series in-line valves. The dashed circles are the air actuator bodies that are located under the table, allowing much higher bake out temperatures. An example of what this looks like in cross section can be seen in the laser turbo pump drawing below.

An example of plumbing under the table, showing valve configuration.

A look at our air pipette system. The blank-off at the end of the helium tank tee piece is where we plan to add additional tanks, e.g. xenon, in the future.

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