A compact time‐of‐flight mass spectrometer for high‐flux cosmic dust analysis

Abstract

[1] Time-of-flight mass spectrometers on spacecraft are the most direct method for determining chemical composition of cosmic dust grains. Miniaturization of these instruments presents many challenges. Larger space-charge effects, greater deviations from the paraxial approximation, and various ion-optical aberrations negatively affect mass resolution in small time-of-flight instruments. We report on the building and testing of an instrument design that may reduce these effects. In addition to a linear reflectron, ions pass through a ring aperture that transmits only those ions with transverse velocity components that fall within a specific range. This novel design focuses ions onto a detector with greatly reduced spherical aberration. Space-charge effects and the effects of impact plate cratering and grid scatter are also reduced using this design. Controlled impacts of iron microparticles at several km/s demonstrate instrument performance. This instrument is suited for characterization of cosmic dust in regions of very high dust flux, such as a comet flyby, and it may also have practical laboratory or field applications.

Simulations of ion trapping in a micrometer-sized cylindrical ion trap

“…Mass spectrometers are attractive targets for miniaturization because they generally exhibit high sensitivity and chemical specificity. Many groups have focused on miniaturizing mass spectrometers, and small mass analyzers based on time-of-flight [1][2][3][4][5][6], magnetic sector [7], linear quadrupole [8], and hyperbolic and cylindrical ion traps [9 -17] have recently been described. The dimensions of some of these mass analyzers are about a millimeter or smaller.…”