Ion guiding accompanied by formation of neutrals in polyethylene terephthalate polymer nanocapillaries: Further insight into a self-organizing process

Abstract

A relatively large yield of neutralized atoms was observed when 3 keV Ar 7+ ions were guided trough polyethylene terephthalate nanocapillaries. Time and deposited-charge dependence of the angular distribution of both the guided ions and the neutrals was measured simultaneously using a two-dimensional multichannel plate detector. The yield of neutrals increased significantly faster than that of guided ions and saturated typically at a few percent level. In accordance with earlier observations, both the yield and the mean emission angle of the guided ions exhibited strong oscillations. For the atoms, the equilibrium was achieved not only faster, but also without significant oscillations in yield and angular position. A phase analysis of these time dependencies provides insight into the dynamic features of the self-organizing mechanisms, which leads to ion guiding in insulating nanocapillaries.

Guiding of Ar7+ ions through a glass microcapillary array

“…The appearance, motion and disappearance of an individual spot may represent the development of charge pathes in a single capillary, transmitting the ions into different directions [5] (see Fig. 1).…”

“…During its time evolution several charge patches are formed in the opposite side of the capillaries leading to regular oscillations in the angular distribution (see Fig. 1) [3][4][5]. According to recent simulations [6,7], for nanocapillary arrays, the self-organizing transmission is determined by the depletion of charge patches via a strongly nonlinear surface conductivity, while macroscopic single glass capillaries guide ions in a different manner, the depletion is far inside the linear (ohmic) regime [8][9][10].…”

Transmission of 16keV Cu− ions through Al2O3 nano-capillaries

“…The guiding phenomenon involves the charging up of inner capillary walls, where incident ions are deflected by the charge patches sequentially formed in the entrance region [7]. Guiding effect has been found in capillaries with different sizes, aspect ratios, different materials and projectiles, in a wide energy range (e.g., 3-100 keV) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In these recent works, time or deposited-charge evolution related to the angular distribution of the guided ions was measured and analyzed in detail.…”

“…Interaction of charged ions with capillaries made from metals [2,3] and insulators [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] has been widely studied both experimentally and theoretically. For metals, it is aimed to the formation of hollow atoms via charge exchange processes under grazing incidence of HCIs at the capillary walls [2,3].…”

Comparison of ion guiding through nanocapillaries and macrocapillaries in insulating materials

“…Finally, at equilibrium, the charge deposition and the discharge via surface and bulk conduction is balanced. After the first investigations of the guiding phenomenon with capillaries in insulating polyethylene terephthalate (PET) ( [3,4] and references therein), several laboratories experimentally studied ion guiding with various insulating materials [5][6][7][8].…”