Time-of-flight mass spectrometers based on a wedge-shaped electrostatic mirror with a two-dimensional field.

Abstract

For most of the last two decades, a considerable effort has been made towards improving time-of-flight mass spectrometry (TOF MS), which has become an irreplaceable instrumental platform for the purposes of performing analytical measurements in life sciences, such as molecular biology, proteomics, medicine, etc. This can primarily be attributed to the ability of TOF MS to rapidly detect and identify nearly any targeted chemical trace with both high precision and accuracy. However, multi-span TOF MS experiments are limited due to aberrations arising from multiple reflection; our proposed scheme will minimize these aberrations. The inhomogeneous accelerating field is generated without using meshes by changing the potentials on the electrodes of the mirror. The ions are extracted from the ion source by short impulse activation of the accelerating electric field. Since the ions are extracted from various points of the source, even ions with identical masses acquire different velocities during acceleration. We have shown that the "rear" ions of the packet catch up with the "front" ions, and packets of ions with identical masses are compressed in the direction of their movement. It is concluded that, by placing the detector in a plane with the greatest compression of ion packets, an enhanced performance of a time-of-flight mass spectrometer is achieved. We have shown that effective spatial-temporal focusing allows a small mass spectrometer to achieve high resolution and sensitivity. We also propose and numerically evaluate a new platform for designing multi-stage and multi-reflective time-of-flight analyzers with wedge-shaped mirrors. We applied the simulation results to the modernization of old equipment and showed that by simply replacing the electrostatic mirror with an optimized one, a significant increase in the analyzing power can be achieved.