METHOD FOR DETERMINING BORON ISOTOPIC COMPOSITION WITH POSITIVE THERMAL IONIZATION MASS SPECTROMETER BY STATIC DOUBLE-COLLECTION

摘要

A method for determining boron isotopic composition with a positive thermal ionization mass spectrometer by static double-collection comprises the following steps: (1) selecting two paratactic Faraday cups with the biggest deflection angles in the Faraday collector to collect m/e 309 and m/e 308 boron isotopic ions respectively, and setting the distance between the two cups as the minimal value; (2) adjusting and determining the Focus Quad and the Dispersion Quad parameters in an ion source optical focusing system; (3) adjusting and determining a collecting mass number of a Faraday collector central cup; (4) scanning the ion peaks and checking a peak center, starting a data collecting and data processing program to conduct a sample determination.