Frequently Asked Questions - Noble Gas Lab

Sample preparation, holding and analysis times vary depending on the number of samples you need analyzed and the type of samples you provide us. For example, tritium samples can take 2 to 6 month due to the time required to allow the ingrowth of helium-3 to measurable levels.

Please contact Wil Mace before shipping samples (wil.mace@utah.edu)

Dissolved and Noble Gas Lab
      University of Utah
      115 South 1460 East, Room 205
      Salt Lake City, Utah 84112-0102

Our advanced diffusion sampler is close to 1" (25.4 mm) at its widest point. We have produced a narrower option with a diameter of 0.79" (20 mm) and are looking at producing even smaller versions.

We do not analyze stable isotopes of oxygen and hydrogen, but we can direct you to the nearby Stable Isotope Ratio For Environmental Research (SIRFER) laboratory. You will need to contact them directly as we are not directly associated with their facilities.

We will need two samples from you: One will be 1000 ml of water collected for tritium analysis through helium ingrowth. The other sample is for the measurement of dissolved helium-3. We accept three different sampling forms for this: copper tubes, standard diffusion samplers, and advanced diffusion samplers. For more information on these sampling methods, please see our how-to section.

For tritium samples, we need 500 ml to process, but require 1000 ml so extra water is available in the case of sample or equipment problems.

A variety of bottles are acceptable for tritium samples. They can either be glass or plastic. One 1000 ml bottle is acceptable, but we prefer two 500 ml bottles. Please avoid thin-walled 'bottled water' bottles, and please tape bottles shut to avoid leakage during shipment. For examples of bottles, please see our tritium collection notes here.

The Utah Noble Gas Lab uses the helium-ingrowth method to measure tiritum concentration in a water sample. In a sealed, degassed flask, tritiated water is allowed to decay into ³He. This gas is then let into the mass spectrometer. Knowing the amount of helium created as well as the time allowed for decay provides enough information to calculate the initial tritium concentration of the water sample. It is important to remember though, that this calculation will only represent the amount of tititum present in the water sample at the time of collection, NOT the initial tritium concentration at the time of recharge; for that calculation you would also need a total dissolved gas sample of the water using either the Cu tube or diffusion sampler methods.

Please contact Wil Mace or Kip Solomon if you need additional information.