Special Delivery

Special Delivery

This summer, WashU received a new and very special instrument: a noble gas isotope ratio mass spectrometer. Rita Parai, an assistant professor in earth and planetary sciences, was there to greet the machine and see it properly installed. To witness the delivery and hear a bit about how the instrument works, see the video above. 

Parai is thrilled that the instrument will allow her and her group to make new discoveries. “We will use it to determine the isotopic compositions of noble gases trapped in rocks from Earth and other planetary bodies,” she explains. “Noble gases are special in that they are chemically inert — they don't participate in reaction chemistry like most of the other elements on the periodic table. However, that doesn't mean that they are boring! The noble gases serve as passive tracers of compounds like water, nitrogen, and carbon dioxide in and on planetary bodies.”

Some of the topics Parai hopes to address in her lab are: the origins of Earth's atmosphere and ocean, the formation of the Moon, and the transport of gases between surface reservoirs and the deep interior in association with plate tectonics. Learn more about her research in the video below!

Fun facts about the mass spectrometer:

  • The mass spectrometer was built in Wrexham, Wales, UK by Nu Instruments.
  • It took Nu about a year to build the instrument, and it's one of the first to be equipped with a new configuration of detectors.
  • The full model name is: Nu Instruments Noblesse HR 5F5M multi-collector noble gas mass spectrometer.
  • Its serial number is NG042, meaning it is the 42nd noble gas mass spec produced by Nu Instruments. (There's a Hitchhiker's Guide joke to be made in there.) Parai did her PhD work on NG003.
  • The instrument is specifically designed for analysis of noble gases. Since these are present in very low abundances in rocks, the challenge is to count as many noble gas ions from your sample as possible while keeping atmospheric contamination at a minimum. The mass spectrometer has a very low total volume and is kept at ultra-high vacuum pressures.
  • Parai is building a custom gas extraction and purification line that will couple with the mass spectrometer. This system will allow them to prepare gas from a wide variety of samples for analysis with NG042.

Videography by Sean Garcia.