New method for calibration of a quadrupole mass spectrometer for hydrogen isotopes measurements

Quantitative analysis of hydrogen isotopes is an essential problem when it comes to accurately determine the performance of ITER hydrogen isotope separation system, or in case of the purity of tritium gas for injection into the Tokamak, to know the level of impurities, in terms of protium and deuterium (H, D). Mass spectrometry is a reliable method to accurately measure low or high concentrations of hydrogen isotopes (H and D) in various gas mixtures. Due to the interferences caused by the triatomic ions formed in the ion source as a result of the interactions between ions and neutral molecules, corrections must be applied in order to get accurate results. In this paper, a new method for calibration of a quadrupole mass spectrometer for hydrogen isotopes (protium and deuterium) is presented, taking into account the contributions and corrections due to the interferences caused by the triatomic ions at the interest m/z ratios. Also, the uncertainty of the measurement and the detection limit of the method are determined. In order to verify the validity of the method, an intercomparison between the results obtained using Fourier-Transform Infrared Spectroscopy method (a FTIR spectrometer) and the quadrupole mass spectrometer (QMS) was performed for the quantitative analysis of hydrogen isotopes.