Kinetic energy filtering

Kinetic energy filtering Measurement of higher energy atomic secondary ions for removing isobaric molecular signals... 

To be effective, it is necessary for the ions traversing the instniment to experience several RF cycles. Thus, unlike magnetic sector instmments, the ions fonned in the ion source of a quadnipole mass filter apparatus are accelerated to only a few eV kinetic energy (typically 5-10 eV). The timescale of the experiment is therefore... 

To estimate the amount of turbulent kinetic energy lost when filtering at a given grid size, it is useful to introduce a normalized model energy spectrum (Pope, 2000) as follows ... 

The capture efficiency of sticky surfaces for dry particles, and of dry surfaces for moist or sticky particles (ascospores or dye particles), agrees reasonably with theory, but dry surfaces are less efficient for dry particles. Theory and experiments on filter efficiency (Dahneke, 1971 Esmen et al., 1978 Ellenbecker et al., 1980) have shown that the critical parameter is the kinetic energy of the particle. Figure 6.4 shows Cp/C, as given by the ratio of catch on non-sticky compared with sticky pine needles (Chamberlain Little, 1980). Also shown are the results of experiments by Ellenbecker et al. (1980) (0.2-//m fly ash particles on 8-fim steel fibres) and Aylor Ferrandino (1985) (Lycopodium particles... 

An ion subjected to the electric field inside the semicircular shaped energy filter will be deflected towards the inner radius r. of the filter. This deflecting force along with the initial kinetic energy of the ion results in a circular trajectory. For the cylindrical layout, the applied voltage U defines the ion energy that can pass the filter as [24] ... 

---