Center for Emerging Energy Sciences

                     

Precision Metrology & Precision Measurement Science:

Fourier-Transform Ion Cyclotron Resonance (FT-ICR) Mass Spectrometer

CEES has modified seven high resolution FT-ICR mass spectrometers for quantification of low mass species.  The original instruments, named advanced Quantra, were last manufactured by Siemens Industry, Inc. (Process Analytics) in 2008.  With an appropriate sampling system, they are capable of quantitatively measuring sub-picomole amounts of ⁴He and ³He in a hydrogen gas background.  The first of these instruments began operation in 2017, with six of them functioning through 2020.  Currently, four of these instruments are fully operational and have a custom inlet manifold containing a hydrogen removal getter for sample pretreatment.  In 2020, all four of these instruments were upgraded with additional cabling to improve the signal-to-noise ratio.  The resulting system exhibits adequate resolution and quantitative measurement capabilities to contribute significantly as a diagnostic tool within climate and energy research.  These high-resolution FT-ICR mass spectrometers have routinely achieved a resolution, R = m/∆m better than 10,000 at mass-3, with a mass resolution that scales as 1/m.  These devices have easily resolved D₂ from ⁴He, and DH from ³He.

   

            

 

This system has also been used to measure ⁴⁰Ar and ²⁰Ne quantitatively, and these measurements have provided real-time air invasion detection into the sample and/or measurement system while helium measurements were being made.  While no concentration measurements of radioactive species have been attempted to date with this system, it is expected to easily resolve DT from D₂H (a 0.0059 Da mass difference) and HT from all other mass-4 species.  The linearity and stability of this system has been demonstrated through repeated periodic calibrations against a known dilute helium-in-balance-hydrogen external standard.  The lowest level of quantification (LLOQ) values for 4He is plotted below.  The average helium LLOQ value is 0.601 ±0.268 picomole.