Publications in Scientific Journals:

E. Gruber, N. Stolterfoht, P. Allinger, S. Wampl, Y. Wang, M. Simon, F. Aumayr:
"Temperature control of ion guiding through tapered capillaries";
Nuclear Instruments & Methods in Physics Research Section B, 340 (2014), 1 - 4.

English abstract:
We investigate the guiding of Ar7+ ions (kinetic energy of 4.5 keV) through a single macroscopic tapered
glass capillary of conical shape as a function of capillary tilt angle with respect to the incident ion beam
direction. At room temperature a minimum in the transmitted ion intensity appears around the forward
direction, which was previously observed and interpreted by a blocking of the transmission by repulsive
Coulomb forces due to a uniformly charged ring shaped region in the centre part of the capillary. By heating
the tapered capillary to temperatures around 100 C and thus drastically increasing the electrical conductivity
of the capillary material we no longer observe a minimum in the transmission curve but the
transmission curve now has its maximum in forward direction. Since the maximum transmission at high
temperature in forward direction is still smaller than the minimum in transmitted intensity at room temperature,
we conclude that even at room temperature and in forward direction the focusing effect due to
guiding is dominant and only partially weakened by blocking. Our experimental results are well reproduced
in simulations using a theoretical model originally developed for straight nano-capillaries.

Capillary guiding Charged particle transport Tapered capillaries Highly charged ions

Created from the Publication Database of the Vienna University of Technology.