Design and Analytical Performance Evaluation of a Cooling Cell for a Quadrupole Mass Spectrometer with Enhanced Resolution and Sensitivity

摘要

Results obtained with two computational approaches for ion motion simulation at a mTorr helium cell are compared with experimentally measured ion images. The first approach utilized COMSOL Multiphysics modeling software, which employs finite element based analysis. The second approach utilized ThermoSIM, an in-house charged particle tracing package, to process potential arrays generated by SIMION software, which employs a finite difference relaxation technique for solving differential equations.[1] The experimental results were acquired on a specially modified triple quadrupole mass spectrometer with an additional cooling cell prior to the Q3 analyzer. Ions of m/z 508 were kinetically cooled in the cooling cell via collisions with helium atoms. In the COMSOL simulation, background gas properties were computed from a non-stationary flow condition. The results from the gas dynamics simulation wrere integrated into the charge particle tracing for the cooling effect evaluation. In the ThermoSIM simulation, optimal condition searching in a large scale provides performance information of the device.