Improving the resolution and sensitivity of an orthogonal time-of-flight mass spectrometer with orthogonal ion injection

Abstract

The theoretical possibilities of increasing the resolution and sensitivity of a time-of-flight mass spectrometer with orthogonal ion injection are considered. The effects are achieved by using inhomogeneous electrostatic fields of special configurations both in the accelerating and focusing parts of the device – a cylindrical immersion objective and a transaxial mirror, respectively. It is shown that the use of an inhomogeneous cylindrical field of a special configuration as an ion accelerator opens up the possibility of a multiple reduction in the energy spread of ions in injected ion packets, associated with the so-called "turnaround time" and, therefore, a significant (two or more times) increase in the limiting resolution of the mass spectrometer. The use of a transaxial electrostatic mirror as a time-of-flight mass analyzer makes it possible to significantly increase the sensitivity of the mass-spectrometer due to the implementation of triple space-time-of-flight focusing of ion packets. Key features include reduced ion energy spread, increased maximum resolution, and improved sensitivity due to triple focusing in space and time of flight. This research lays the foundation for expanding the capabilities of time-of-flight mass spectrometry, providing a more efficient and powerful tool for a wide range of scientific and industrial applications. The effects are achieved by using inhomogeneous electrostatic fields of a special configuration in both the accelerating and focusing parts of the device – a cylindrical immersion lens and a transaxial mirror, respectively. Numerical calculations of the system – a four-electrode cylindrical immersion lens in combination with a three-electrode transaxial mirror – are presented, which confirm the conclusions of the theory