Berkout Vadym D, Doroshenko Vladimir M
MassTech, Inc., Columbia, Maryland, USA.
J Am Soc Mass Spectrom. 2006 Mar;17(3):335-40. doi: 10.1016/j.jasms.2005.12.002. Epub 2006 Jan 30.
The effect of fringing fields on the divergence of the ion beam exiting an RF quadrupole ion guide was studied using a computer simulation. It was shown that reducing the strength of the RF field towards the ion guide exit reduces ion beam divergence. Further improvement was demonstrated when creating a DC gradient towards the exit. The results of the numerical simulation were verified experimentally using a time-of-flight (TOF) mass analyzer with orthogonal acceleration. Decreasing the ion beam divergence resulted in considerably improved mass resolution of the instrument.
利用计算机模拟研究了边缘场对从射频四极杆离子导向器射出的离子束发散度的影响。结果表明，朝着离子导向器出口降低射频场的强度可减小离子束发散度。当朝着出口创建直流梯度时，展示出了进一步的改进。使用具有正交加速功能的飞行时间（TOF）质量分析仪通过实验验证了数值模拟的结果。减小离子束发散度使得仪器的质量分辨率得到了显著提高。
