A new method for electrostatic ion deflection

Abstract

A new approach to electrostatic ion deflection is described where an electrostatic particle guide (EPG) operating with reversed polarity is used to deflect ions in a cylindrical geometry about the axis of a time-of-flight mass spectrometer. The method has advantages over the standard parallel-plate deflector geometry in that it is more effective in deflecting ion beams that have a significant radial velocity component. The device is being used in (252)cs Cf plasma desorption mass spectrometry ((252)cs Cf -PDMS) experiments in an on/off mode to record neutral particle spectra and in a synchronized pulsed mode to reduce the magnitude of the uncorrelated background in the time-of-flight spectrum. Radial distribution functions have been measured for various EPG voltages. Its use as a background suppression technique is demonstrated by using the (252)cs Cf-PDMS spectrum of insulin. (28-36).

Gridless Ion Acceleration Systems for Time-of-Flight Mass Spectrometry

“…The proton intensity should be a much more reliable indicator of an enhanced ion transmission. Surprisingly, the gridless system exhibits a 30% higher proton intensity that cannot be totally explained by the absence of the grid; but it is known that protons are desorbed with very high divergencies by fission fragments [9,10] and that a grid increases the beam diver- The first TOF MS experiments employing such an optimized lens yielded the expected performance: The ion yield increased owing to the absence of a grid and the reduced beam divergence, whereas the mass resolution decreased. The decrease in mass resolution is due to the weak ion extraction field.…”

“…demonstrate the influence of thickness d on the ion front curvature (U] is adjusted to yield a parallel beam). Obviously, the curva-to an eventually increased beam divergence are most likely indicated by a decreased yield of protons[9, 10].…”

A miniaturised electron ionisation time-of-flight mass spectrometer that uses a unique helium ion removal pulsing technique specifically for gas analysis

“…However, too many carrier gas ions would cause saturation of the MCP, particularly when its intake amount is large, and the lifetime and working performance of the MCP would be substantially degraded. Currently, the removal of major carrier gas ions is based on the front-end ion source 18,19 and ion transfer system technologies. 17 For this purpose, two primary measures are taken, namely, to prevent the formation of carrier gas ions and to deect and separate the carrier gas ion beam using a magnetic eld.…”

Stacked-ring electrostatic ion guide

“…Unfortunately, Laplace's equation disallows the generation of such a potential minimum in free space by applying static voltages to the electrodes of a finite-length ion guide. However, ions may be transported through a hollow cylinder with a more negatively biased wire running down its central axis (Figure 1, top) [17][18][19][20][21]. Although the wire ion guide has the advantage of simple construction, ions without sufficient initial transverse velocity may be neutralized -vo…”