Mass-resolved ion microscope imaging over expanded mass ranges using double-field post-extraction differential acceleration

Abstract

Mass-resolved ion microscope imaging over expanded mass ranges using double-field post-extraction differential acceleration,

High-Resolution Ion Microscope Imaging over Wide Mass Ranges Using Electrodynamic Postextraction Differential Acceleration

“…These results are consistent with the simulation (red trace) and with the expected resolution of the ion microscope with and without a PEDA pulse applied. 21 , 28 , 33 …”

“… 25 It is also a simpler alternative to the many-field PEDA approach that can be applied without modifying or adding new electrodes to an ion optical system. 28 , 34 Only the applied pulse to the extraction electrode is changed. In these experiments, an approximately linear potential rise was used.…”

“… 33 The linear configuration was used here to better compare the data with previous experiments, which shared the same ion optical system but a shorter drift distance. 28 The ion optical dimensions are therefore the same as those used for Figures 1 b and 2 but with L D ≃ 240 cm. The instrument is also not perfectly linear; the ions were deflected by 3° toward the detector using two parallel plate electrodes held at ±157.2 V and placed 72.1 cm from the exit of the einzel lens.…”

“… 25 Using this method, we showed that the mass range over which the mass resolution of our ion microscope reached at least half that of the focused m / z (410 Da) was just ∼8% of the 300 Da range that could simultaneously be spatially resolved. 27 , 28 …”

“…For example, the mass-resolved range of the above experiment can be extended to cover ∼20% of the spatially resolved window using the double-field PEDA method, where the acceleration region is divided in two by an electrode that is raised to a higher potential at the same time as the extraction electrode. 28 The potentials of the two electrodes were set to create a cusp in the potential energy surface between the two acceleration regions, such that heavier ions in the “early” region achieved temporal overlap at the same drift distance as lighter ions in the “late” region. This approach could in principle be extended to a many-field method using additional electrodes to focus broader mass ranges.…”