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Syracuse University Noble Gas Laboratory (SUNGIRL)


Micromass 5400 Noble Gas Mass Spectrometer and Extraction Line

The laboratory employs a custom built furnace, CO2 and UV lasers, and ultrahigh vacuum extraction line connected to a 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 sensitivity 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. 

VG5400 noble gas mass spectrometer

5400 Noble Gas Mass Spectrometer

The extraction line for the 5400 consists of an all-metal system. Samples are outgassed using a double vacuum resistance-heated tantalum furnace, or CO2 laser or UV laser. The furnace is controlled via a Eurotherm 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.


Furnace and UHV extraction line

5400 extraction line


 


Quadrupole and He extraction line

Helium determinations for (U-Th)/He analyses are made using a dedicated quadrupole mass spectrometer and UHV gas handling system.  A double vacuum resistance-heated furnace or CO2 laser is used to outgas samples. Our 4He blanks are routinely on the order of <0.001 ncc. Helium outgassed from samples is purified in the all-metal extraction line. Gettering of active gasses is handled by small, standard SAES getters. Reservoirs containing a 3He spike and a 4He standard are attached to the line behind all metal pipettes. Our 4He pipette delivers 9.84 +0.08 ncc STP 4He per aliquot. Measurement of 4He is done by isotope dilution, using a 3He spike. Measurement of U and Th concentrations are presently performed by solution ICPMS at UA. A Janis cryogenic cold trap system is interchangeable between the He extraction line and the 5400 extraction line when required.


Quadrupole mass spectrometer and extraction line

Quadrupole mass spectrometer