High-accuracy measurements with a quadrupole mass spectrometer

The paper considers measured ratios between the 131 m/e and 132 m/e ion peaks with intensity (area) ratio of 1 : 0.03 in the perfluorotributylamine mass spectrum with σ varying within the range of 0.005÷0.008 % (the small peak with respect to the large peak). Conditions under which the said measurement accuracy of those peaks ratio have been analysed. The measurements has been performed by quadrupole mass spectrometer МС7303 with the modified computer system. The direct goal of this investigation was to acquire technical information necessary to construct, for Research-Engineering Center NTT "Tsentrotekh-EHZ", a quadrupole mass spectrometer suitable for high-accuracy (0.002 %) measurement of silicon isotopic composition in SiF4 in the scope of the International Project aimed at creation of a New Mass Standard. The Project participants are Germany, Great Britain, France, Japan, USA, Australia, and Russia; on the part of Russia, the investigation is performed by NTT "Tsentrotekh-EHZ", branch of FGUP "PO EHZ" (leading organization), A.F. Ioffe PTI RAS, IHVV RAS and Radium Institute.