Method for determining boron isotopic composition by PTIMS—static double collection

摘要

A method for determining boron isotopic composition by PTIMS (Positive Thermal Ionization Mass Spectrometry)-static double collection realizes simultaneous static collection of m/e309 peak and m/e308 peak by double Faraday cups through adjusting the two parameters Focus Quad and Dispersion Quad in Zoom Optics, and completes high-accuracy determination of boron isotopic composition. The method includes (1) determining Focus Quad and Dispersion Quad parameters in the Zoom Optics of the ion source; (2) determining the two parallel cups in the Faraday collector and their parameters; (3) determining the collection mass number of the center cup of the Faraday collector. The method of the present invention establishes a method for determining boron isotopic composition by static collection with double Faraday cups under the condition of not changing high voltage parameters and Faraday cup hardware setting, greatly shortens data acquisition time compared to the dynamic peak jumping method, and improves the sensitivity and internal and external accuracy of the determination of boron isotopic composition by PTIMS.