A calculation method to eliminate gain effect on isotopic measurement using the virtual amplifier multi-collector mass spectrometer

The virtual amplifier design employed in the ThermoElectron multi-collector mass spectrometers is a novel innovation for high precision isotopic measurement. With the virtual amplifiers, uncertainties of gain factors of amplifiers can be effectively averaged out, so that accuracy and external reproducibility on isotopic measurement can be improved. This paper presents a new calculation method on isotopic measurement using the virtual amplifier mass spectrometers such as ThermoElectron Triton and Neptune. With the calculation method, gain factors of the amplifiers can be completely eliminated out for both raw measured isotopic ratios and normalized isotopic ratios when exponential or power law is used to correct isotope fractionation effect, and therefore, gain calibration is unnecessary even for the high precision measurement purpose.