Scanning-assisted focal plane-detection system for a sector-field mass spectrometer - Part-I: Simulation and data processing

Abstract

In this paper, a novel detection system, the Scanning-Assisted Focal Plane-Detection System (SAFPDS), is proposed as a focal plane detector for sector-field mass spectrometers. The principle of SAFPDS is to decouple the spatial resolution and local count rate of the microchannel plate (MCP) focal plane-detection system in order to enhance the local count rate and dynamic range limited by the MCP. This decoupling is achieved by deflecting ions along the vertical direction of the focal plane detector using an ion deflector during acquisition. Simulations of the SAFPDS are reported for optimal geometrical design, operation, and performance. Additionally, a dedicated novel data processing protocol for deriving a representative mass spectrum from the 3D-recorded data obtained with SAFPDS is developed in combination with the SAFPDS hardware. Our study shows that this protocol effectively enhances the spectrometer's Figure of Merit (FOM), defined as the integral of the mass resolution (m/Δm) over the relevant mass range, by a factor of 2.4. Furthermore, the evaluation of the spectrometer equipped with SAFPDS highlights its capability to enhance the local count rate and dynamic range of sector field mass spectrometers with an MCP-based detector by at least one order of magnitude. Importantly, this enhancement is achieved with a deterioration in mass resolving power that remains below 30%, which we consider acceptable given the significant improvements in local count rate and dynamic range.