Dynamic properties of ion guiding through nanocapillaries in an insulating polymer

Abstract

We studied the dynamic properties of ion guiding through nanocapillaries in insulating polyethylene terephthalate. The angular distribution of the transmitted ions was measured as a function of the charge deposited on the sample surface, which is a measure of time. The time evolution of the angular transmission profiles was acquired for the capillary diameters of 200 and 400 nm. The tilt angle was varied from 0°to 6.5°. The transmission profiles appear as a superposition of essentially three localized peaks which exhibit significant changes in intensity as time varies. This observation provides evidence for the formation of temporary charge patches produced in the interior of the capillary besides the primary charge patch created in the entrance region.

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

“…So it is important to reduce both the ion beam size and its divergence, as well as to improve the target quality in next step. For HCIs guiding, it was generally accepted [4,15,16] that the positive charge can be deposited at the inner walls of capillaries in a self-organizing process and then can inhibit further contact of the incident ion with the capillary walls. In this way, HCIs have an ability to preserve their initial charge states through nano-capillaries.…”

“…In these recent works, time or deposited-charge evolution related to the angular distribution of the guided ions was measured and analyzed in detail. The evidence for the formation of temporary charge patches on the inner wall of the capillary, coexisting with the primary charge patch created in the entrance region, was sufficiently provided [16]. Therefore, the capillary guiding is regarded as the result of electrostatic field induced by deposited charge patches on the inner wall of the capillary in a self-organizing process [4,15].…”

“…This is the so-called guiding effect. 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].…”

“…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].…”

Guiding of Ar7+ ions through a glass microcapillary array

“…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].…”