Scaling laws for guiding of highly charged ions through nanocapillaries in an insulating polymer

Abstract

Guided transmission of highly charged ions through nanocapillaries in insulating PET polymers was investigated. Samples with highly parallel capillaries were used to study the ion guiding with a variety of ionic species, such as Ne 7+ , Ne 9+ , Ar 9+ , Ar 13+ , and Xe 25+ . The incident energy was varied within the range of 3 − 40 keV. The fraction of transmitted ions was measured as a function of the capillary tilt angle. The results are used to evaluate the guiding angle, which is a measure of the guiding power specifying the ability of a material to guide ions. Moreover, the angular profile of the transmitted ions was studied as a function of their energy and charge state. The profile width and the guiding angle were found to follow the same scaling law indicating that they are both determined by the main charge patch in the entrance region of the capillary.

Density effects on the guided transmission of 3keV Ne7+ ions through PET nanocapillaries

“…The results are used to determine guiding angles. As expected, the results for the high capillary density of 1 Â 10 8 cm À2 agree with recent studies devoted to scaling rules for the ion guiding [22]. However, profile widths obtained for the low capillary density of 4 Â 10 6 are found to differ significantly from the previous results.…”

“…Recently, similar scaling rules were found for the guiding angle and the width of the emission profile [22], which are governed by the potentials in the entrance and exit regions, respectively. In particular, the width of the emission profile was found to be independent on the tilt angle.…”

“…However, to produce a reasonable field in the exit region, it has to be supported by patches in neighboring capillaries [5,21]. The previous results, on which the scaling laws are based [22], have uniquely been obtained with capillaries of high density of 1 Â 10 8 cm À2 . We expect, however, that the neighbor effect depends on the capillary density.…”

“…It has recently been shown [22] that the profile width angle a t and the guiding angle w c can be obtained from the simple expressions…”

Ion guiding in alumina capillaries: MCP images of the transmitted ions

“…Non-parallelism may strongly influence the guiding parameters, especially the width of the angular distribution [11,12]. In order to study the geometric properties of the samples, we measured the transmission of 90 keV Ne 6+ ions by a current-measurement technique.…”