Experiments and simulations of 4.5-keVAr7+−ionguiding through a conical glass macrocapillary

Abstract

Experimental and theoretical studies are performed to investigate guiding of 4.5-keV Ar7+ ions through a conical macrocapillary. The tilt angle of the capillary axis relative to the incident beam is varied within 0 J-2°. The experiments are performed using a glass capillary whose bulk conductivity could be varied by changing its temperature from 24 C -l 10 C. At lower temperatures a minimum in the transmitted ion intensity is observed in the forward direction. After strongly increasing the electrical conductivity of the capillary by increasing its temperature to 110 C, the transmission profile becomes geometrical without a forward minimum. The experimental data are compared with theoretical results, which are based on simulations previously developed for nanocapillaries and a straight macrocapillary. Both the surface and bulk conductivities are implemented in the calculations, providing clear evidence that the bulk conductivity is dominant. The major experimental features are reproduced by the simulations, providing evidence for the mechanisms producing the forward minimum.

Stabilizing the ion-beam transmission through tapered glass capillaries

“…By varying the angle β between the capillary and the beam axis, a maximum of f c = 3 was found for β = 0.3 deg in Refs. [9,10] and a maximum of f c = 8 for β = 0.75 deg in Ref. [8].…”

“…Experimental evidence of transverse compression by tapered capillaries tilted with respect to the beam axis was given in Refs. [8][9][10]. By varying the angle β between the capillary and the beam axis, a maximum of f c = 3 was found for β = 0.3 deg in Refs.…”

Spatial and temporal distribution of a 1-MeV proton microbeam guided through a poly(tetrafluoroethylene) macrocapillary

“…Applying this crude model, N times the lower number of primary projectiles is needed in the simulation. The value of N is typically between several thousand [29] and several ten thousand [30] for slow, highly charged, and/or slow ions. For 1-MeV protons test simulations showed that even in the case of N = 10 6 the trajectory is only slightly modified, which can be explained by their large electrical rigidity.…”

Stabilizing the ion beam transmission through tapered glass capillaries

“…Beam compression by patches in capillaries was demonstrated using simulations in [6] and [2], with the latter including a detailed discussion of the involved mechanism. Experimental evidence of transverse compression by tapered capillaries tilted with respect to the beam axis was given in [7][8][9]. By varying the angle β between the capillary and the beam axis, a maximum of f c = 3 was found for β = 0.3 deg in [8,9] and a maximum of f c = 8 for β = 0.75 deg in [7].…”

“…Experimental evidence of transverse compression by tapered capillaries tilted with respect to the beam axis was given in [7][8][9]. By varying the angle β between the capillary and the beam axis, a maximum of f c = 3 was found for β = 0.3 deg in [8,9] and a maximum of f c = 8 for β = 0.75 deg in [7]. In both cases, no enhancement was found for zero tilt angle, excluding thus the possibility that the enhancement was due to axially symmetric self-organized potential.…”