Dissolved and Noble Gas Lab

Mass Spectrometry Lab for Groundwater and Age Dating Research 

Dr. D. Kip Solomon, Professor and PI
801-581-7231
kip.solomon@utah.edu

Alan Rigby, lab manager
801-585-5214
alan.rigby@utah.edu


College of Mines and Earth Sciences
115 South 1460 East, Room 205
Salt Lake City, Utah 84112

Instrumentation

The analytical system consists of two Mass Specs: a quadrapole Mass Spec and a magnetic sector-field Mass Spec.  The quadrapole can be used to quickly determine the abundance and isotopic analysis of most atmosphere gases, including Ne, Ar, Kr and Xe.  The sector-field Linear Mass Spec is designed for precise measurements of 3He and 4He.  Presently, the system is designed to detect the abundance of the five stable noble gases (He, Ne, Ar, Kr, and Xe) in groundwater or as fluid inclusions in rocks or minerals.  The water line is used to extract noble gases from groundwater.  The rock line is outfitted with a rock crusher and a furnace where the samples can be crushed or heated to release gases from fluid inclusions or from the crystal lattice.  Samples are loaded into the mass spectrometer purification line under high vacuum 10-9 torr allowing for a lower detection limit.  Purification consists of a series of cryogenic cold traps and getter traps and measurements are made by either an electron multiplier (for high-precision analysis of low abundance isotopes) or a Faraday cup for highly abundant isotopes.

Noble Gas Lab

Age dating using 3H/3He, 3He and CFC’s


Groundwater dating is accomplished by measuring the concentrations of both tritium (3H) and helium-3 (3He).  Tritium is a naturally occurring hydrogen isotope.  Natural production of tritium is small compared to the amount of tritium released during atmospheric atomic bomb testing conducted in the late 1950’s through mid 1960’s.  These atmospheric atomic bomb tests bolstered the concentration of tritium in the atmosphere resulting in traceable tritium spikes over most of the world.   Tritium decays to helium-3 with a half-life of 12.4 years.  Thus, measurements of both the parent and daughter isotopes provide a means of computing the age of the water.  Surface exposure ages of rocks are also possible using He because cosmic rays that bombard silicates produce 3He via a nuclear reaction; the more 3He a rock has the longer it has been exposed at the earth’s surface. 
The CFC portion of the lab is used to detect the concentrations of Chlorofluorocarbons (CFC) in groundwater.  CFC’s are a man made organic compound utilized in a wide range of industrial and domestic purposes.  CFC gases have been released into the atmosphere over the last 50 years.  Concentrations of CFC in the atmosphere have increased over time due to increased commercial usage and in part to relatively long atmospheric residence times that range between 44 to 180 years. Precise CFC measurements have been conducted beginning in 1978 throughout the globe as a part of the Atmospheric Lifetime Experiment, producing an excellent recorded record of global CFC concentrations.  Partitioning of atmospheric CFC into water vapor depends on the atmospheric concentration and the solubility relationships.  Infiltration of meteoric water into the subsurface carries dissolved CFC gases.  Once isolated from the atmosphere the concentration of CFC’s in water remains constant.   When a groundwater sample is obtained and analyzed for the CFC concentration, the concentration in the water is related to the concentration of CFC in the atmosphere at the time the water entered the subsurface and an age can be determined. 

     Environmental Tracer Lab

UNIVERSITY OF UTAH
DISSOLVED AND NOBLE GAS LABORATORY

SERVICE AND PRICE LIST 

Off Campus – 2009                                                                                                                
 
Tritium (3H) analysis using helium in-growth method        
                                                                        
•    Tritium concentration data not available until after 2 to 6 month holding period
•    All analytical work included
•    Reported precession for tritium: ± 3% of value
•    Detection limit depends on holding period; typically 0.1 TU
Price: $305.02

Dissolved-gas measurements using diffusion sampler method

•    All analytical work included
•    Includes the following analysis:  28N2, 40Ar, 20Ne, 84Kr, 129Xe, 3He and 4He
•    Reported precession for helium: ± ½ to 1% of value
•    Reported precession for all other gasses:  ± 1% to 3% of value
Price: $321.41

Dissolved-gas measurements using copper tube method

•    All analytical work included
•    Includes the following analysis:  28N2, 40Ar, 20Ne, 84Kr, 129Xe, 3He and 4He
•    Reported precession for helium: ± ½ to 1% of value
•    Reported precession for all other gasses:  ± 1% to 3% of value
Price: $361.89

Dissolved-gas measurements for CFC analysis using bottle method

•    All analytical work included
•    Includes the following analysis:  CFC-11, CFC-12 and CFC-113
•    Samples collected in triplicate
•    Reported precession for CFC: ± 5% of value
Price: $200.00

Shipping / Handling / Materials / Other

•    Shipping and handling fees will be additional
•    Damaged equipment will be invoiced
•    Analytical work beyond stated scope will be additional
•    Other sampling configurations possible, please contact the laboratory for options 
•    IMPORTANT - Contact laboratory prior to sample collection at 801-585-5214
•    Pricing subject to change


Last modified 05-18-09