Isotope Ratiometer

The isotope ratiometer is a new technique developed at the Rutherford Appleton Laboratory used to measure the ratio of stable isotopes 13C:12C (δ13) for CO2. The novel configuration allows the instrument to compact robust and offer very high precision in real time.







Isotope Ratio Mass Spectrometry (IRMS) has long been the “gold standard” analysis tool for stable isotope studies, in spite of considerable practical limitations, because it delivers the requisite precision and because there was no viable competitive technology. Laser based techniques have been developed that overcome several limitations of IRMS. However laser techniques developed to-date rely on high reflectivity optics in order to achieve near equivalent precision as IRMS. This adds considerable expense and significantly impacts robustness to the system design. The standard approach used is to target spectrally neighbouring 12CO2 and 13CO2 transitions using a single tuneable laser, however this has several downfalls.



  • Immune to temperature variations. The two transitions were carefully selected as they are equal in absorption strength and have the same intensity temperature dependence.
  • High Precision (~0. 1 ‰ /1s). As the detection method overcomes temperature dependence and the concentration of both 12CO2 and 13CO2 are optimally measured, the isotope ratiometer offers highly competitive precision.
  • Small and Robust (~30cm x 30 cm x 30 cm). The technology is not constrained by high reflectivity optics, allowing the system to be highly compact and robust. Furthermore the immunity to temperature variations implies no need for complex sampling methods.



  • Breath diagnostics
  • Environmental sciences
  • Oil and gas exploration
  • Food processing and safety


Patent Information:
Country Serial No.
United States 11/606084
United States 12/197859
India 1870/MUMNP/2010
China 200880128650.7
Canada 2715157
France 08709427.2
Sweden 08709427.2
Italy 08709427.2
Spain 08709427.2
Germany 08709427.2
Switzerland 08709427.2
Netherlands 08709427.2
United Kingdom 08709427.2
For Information, Contact:
Elizabeth Bain
IP Manager
STFC Innovations
+44 (0) 1925 60 3680
01.h. Imaging & Detector Technology
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