ISSN 10637397, Russian Microelectronics, 2012, Vol. 41, No. 5, pp. 299–309. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © V.A. Zhukov, P.V. Shpartko, 2012, published in Mikroelektronika, 2012, Vol. 41, No. 5, pp. 340–350.
In the past decade, the transit effect of multicharge
ions through a thin dielectric channel without a loss of
energy and charge, or the socalled ion guiding effect,
was discovered [1–7]. Initially, the ionguiding effect
through the PET (polyethylene terephthalate) tube
was found. This effect was experimentally confirmed
by other authors for various dielectric materials of
tubes or plates, various ions, and at various accelerat
ing voltages. In this work, we will focus our attention
on the development of a model of the ion guiding
effect in conical capillary tubes (Fig. 1). We can distin
guish several important experimentally found proper
ties of ion passing through such tubes.
(i) The current measured at the tube output
increases monotonically, reaching saturation over time.
(ii) When passing through a conical capillary tube,
the ion beam is concentrated into the axially symmet
ric spot with an area considerably smaller than the area
of the input tube orifice.
(iii) After reaching the state of charge saturation in
the dielectric capillary tube, multicharge ions retain
their charge after transiting through the tube and, con
sequently, retain their potential ionization energy,
which is ~930 eV for the
ion according to our
(iv) After reaching the charge saturation state on
the walls in the dielectric capillary tube, multicharge
and singlecharge ions retain their kinetic energy after
transit through the tube.
Thus, after reaching the saturation state in the
dielectric capillary tube, multicharge ions elastically
(with no loss of the kinetic and internal potential
energy) interact with the inner tube surface. The total
internal reflection of ions from the walls, which is sim
ilar to the total internal reflection of the light from the
walls of the dielectric waveguide, takes place.
Authors of experiments [1–4] note that the ion
current in the output orifice of the hole, the area of
which is smaller than the area of the input orifice by 4–
5 orders of magnitude, can be obtained equal to the cur
rent at the tube input; i.e., the tube concentrates the ion
beam. This means that the ion guiding effect could find
its application in the electronoptical systems widely
demanded in physics, biology, and medicine.
Despite the large number of experimental confir
mations of the effect, a strict physicomathematical
model of the ion guiding effect has still not been devel
oped. A strictly substantiated model could eliminate
discrepancies in the experimental data and help reveal
the optimal parameters of the system. In this work, we
consider the transit of singlecharge and multicharge
ions through a short dielectric ring narrowing to one
end, or a part of a thin conical capillary tube. Since
such a ring focuses the ion beam passing through it, it
can be used as the ion lens in exact electronoptical
devices such as microscopes, spectrometers, and par
ticle accelerators. Such an ion lens solves problems
other than the capillary tube, which is primarily a
channel similar to a light guide in terms of its action.
The region of using the electron lenses is much wider
than that of light guides. Therefore, we considered the
dielectric ring as potentially more in demand in sci
ence and technology.
2. STATEMENT OF THE PROBLEM
We took the input data to construct the model from
one successful experiment , in which researchers
ElectronOptical Properties of Charged Conical Dielectric Rings
V. A. Zhukov
and P. V. Shpartko
St. Petersburg Institute of Information Science and Automation, Russian Academy of Sciences,
Chetyrnadtsataya liniya, St. Petersburg, 199179 Russia
St. Petersburg State Polytechnical University, ul. Politekhnicheskaya 29, St. Petersburg, 195251 Russia
email: email@example.com, firstname.lastname@example.org
Received February 10, 2011
—The numericalandanalytical model of charging the conical dielectric ring with a beam of inert
gases, which is parallel to its axis and has a constant bulk density, is developed. It is shown that such a ring can
be used as a lens in the charged steady state. It is shown that with an input diameter of 0.8 mm, an angle
between the cone generatrix and the axis of 10
rad, and a length of 1 mm, this lens has a focal distance of
3.4 mm, a spherical aberration coefficient of 760 m, and a coefficient of chromatic aberration of 14 mm. Such
a lens can be used as an objective in an ion microscope, which is comparable with the best modern ion micro
scopes by resolution. However, such a device will be considerably cheaper.