Characteristics of electrical field and ion motion in surface‐electrode ion traps

Abstract

In this article, we calculated the potential function of the surface-electrode ion trap (SEIT) by using Green's function method, optimized trap size, obtained the coefficients of the multipoles and analyzed ion trajectories in the RF potential. The optimized SEIT not only increases its trapping well depth by a factor of about 15, but also has relatively good linearity of the field (or large quadrupole component). The current design of SEIT can work well either as the ion guide for ion transmission or as the ion trap for ion confinement. Our research can be used to calculate the potential function in the SEIT with different device parameters, understand ion motions in the traps and optimize instrument performance. The method for calculating potential function can be expanded to planar and halo ion traps.

Following the Ions through a Mass Spectrometer with Atmospheric Pressure Interface: Simulation of Complete Ion Trajectories from Ion Source to Mass Analyzer

“…These steps were repeated to produce an ion trajectory within a specified time period. Ion trajectories were calculated using the Runge–Kutta (R-K) method, − in which the time step was chosen as the smaller one between 1/20 of an RF cycle (5 × 10 –8 s for 1 MHz) and the actual collision-free time. This means that the time step in simulation was pressure-dependent.…”

Flowing gas in mass spectrometer: method for characterization and impact on ion processing

“…The ion was placed at the center of the pinhole, entering the Einzel lenses with an initial axial velocity v z = 400 m/s and an initial radial velocity v r =30 m/s. The total simulation time was 0.1 ms with a time step at 10 −8 s for the Runge-Kutta method, 46–48 which was much shorter than the mean free time (Figure 2S and 3S in Supporting Information). The combinations of the fields included (i) dynamic gas field only, (ii) E field only, (iii) E field with static gas field, or (iv) E field with hydrodynamic gas field.…”

“…The ion was placed at the center of the pinhole, entering the Einzel lenses with an initial axial velocity of v z ¼ 400 m s À1 and an initial radial velocity of v r ¼ 30 m s À1 . The total simulation time was 0.1 ms with a time step of 10 À8 s for the Runge-Kutta method, [46][47][48] which was much shorter than the mean free time (Fig. 2S and 3S in the ESI †).…”

“…Within a distance of L , the ion can be assumed to have a collision-free motion guided only by the electric field. 12, 46, 47 Subsequently, an ion-neutral collision occurs, and the actual velocity of the gas molecule at the collision is sampled using the Eq. 1.…”

“…Within a distance of L, the ion can be assumed to have a collision-free motion guided only by the electric eld. 12,46,47 Subsequently, an ion-neutral collision occurs, and the actual velocity of the gas molecule at the collision is sampled using eqn (1). The velocity vector of the ion modied by the collision can then be used for the collision-free motion under an electric eld in the next step of the simulation.…”