Crowd control of ions in the Astral analyzer.

Space charge effects are the Achilles' heel of all high-resolution ion optical devices. In time-of-flight mass analyzers, these may manifest as reduction of resolving power, mass measurement shift, peak coalescence, and/or transmission losses, while highly sensitive modern ion sources and injection devices ensure that such limits are easily exceeded. Space charge effects have been investigated, by experiment and simulation study, for the astral multi-reflection analyzer, incorporating ion focusing via a pair of converging ion mirrors, and fed by a pulsed extraction ion trap.

Numerical simulation of ion transport in an atmosphere-to-vacuum interface taking into account gas dynamics and space charge.

A two-step approach was developed for the study of ion transport in an atmospheric pressure interface. In the first step, the flow in the interface was numerically simulated using the standard gas dynamic package ANSYS CFX 15.0.

Gas Flow in the Capillary of the Atmosphere-to-Vacuum Interface of Mass Spectrometers.

Numerical simulations of a gas flow through a capillary being a part of mass spectrometer atmospheric interface were performed using a detailed laminar flow model. The simulated interface consisted of atmospheric and forevacuum volumes connected via a thin capillary. The pressure in the forevacuum volume where the gas was expanding after passing through the capillary was varied in the wide range from 10 to 900 mbar in order to study the volume flow rate as well as the other flow parameters as functions of the pressure drop between the atmospheric and forevacuum volumes.

Some aspects of space-charge effect calculation in high-resolution mass spectrometry.

A variational 3D approach to the problem of simulating stationary distributions of ions in the radiofrequency low-vacuum ion traps with regard to Coulomb interaction and collisions of ions with buffer gas molecules is proposed. The software developed in the course of this work is employed to study the structure of stationary ion ensembles in the radiofrequency ion traps of various types. The effect of high-frequency and constant voltages, space-charge density, and buffer gas temperature on the formation of stationary distributions in the radiofrequency ion traps and their limiting capacitance is investigated.

Space-charge effects in an electrostatic multireflection ion trap.

The multireflection ion traps with isochronous properties offer a Lot of opportunities for time-of-flight mass spectrometry by elongation of the ion path, thus preserving the compact dimensions of an instrument. We have built and tested a two-mirror linear trap that provides at least 80,000 mass-resolving power. Although the mass resolution appears promising, there are substantial limitations that arise from Coulomb interactions of the trapped ions.