Properties of fast carbon cluster microbeams produced with a tapered capillary

Abstract

a b s t r a c tWe study the transmission properties of fast cluster ions (C n + (n = 2-4) with velocities ranging from 0.89 to 1.79 a.u.) through a single tapered capillary with an outlet diameter of 13.7 lm. We investigate the projectile-velocity dependence of the transmission fraction from the measurements of transmitted particle energy spectra. It is found that the non-fragmentation fraction of C 2 + projectiles increases with decreasing velocity, indicating that fragmentation occurs mainly via close collisions with the surfaces of the capillary wall. For C n + (n = 2-4) ions with the same incident velocity, the cluster-size dependence of the non-fragmentation fraction shows even-odd alternation, implying that the fraction includes contributions from stable clusters surviving the grazing scattering process at the capillary surface. We also find that the angular distribution of transmitted particles is narrower for cluster projectiles compared with atomic projectiles.

Transport of accelerated electrons through dielectric nanochannels in PET films

“…To describe the observed effect, the authors of work [5] introduced the term "guiding" and explained the guiding effect is due to the deposited charge from the ion impact on the insulating surfaces which prohibit the following ions from close collisions with the capillary walls. The guiding effect was also observed for other types of ions with different energies [6]- [8]. So far, the guiding scenario for the positive ions are widely accepted and clear.…”

Charge-state distributions of fast diatomic carbon ions and dissociated fragments passing through microcapillaries

“…The apparatus and experimental procedure are essentially the same as our previous study [8] and only a brief outline is given. Figure 1 shows the experimental setup.…”

“…We employed borosilicate glass capillaries with two different outlet diameters of 7.7 and 13.7 μm. The latter capillary was entirely the same as that used in our previous study (details of the capillary characteristics were described in [8]). The taper angle in the exit region was 0.1 • or less.…”

“…The molecular transmission studies have been reported for the first time by Stolterfoht et al for slow H 2 + and H 3 + ions through PET nanocapillaries with 100 nm diameter [7], who observed the transmission phenomenon without fragmentation. Recently, we have studied the molecular fragmentation during the transmission through a single-tapered microcapillary for fast polyatomic C n + (n = 2-4) ions with velocities ranging from 0.89 to 1.79 au [8]. The study showed that the fragmentation proceeds with increasing velocity.…”

Ion guiding in macro-size insulating capillaries: straight, tapered, and curved shapes

“…Although a realistic value of the enhancement factor may be considered to be less than 2, the work of Nebiki et al demonstrated that a tapered glass capillary can be used as a simple microbeam generator to achieve some beam density enhancement. The capillary microbeam method has since been applied to particle induced x-ray emission (PIXE), RBS (Rutherford backscattering spectrometry), and nuclear reaction analysis with various MeV-energy ions [87][88][89][90][91][92][93][94][95][96][97][98]. The RIKEN group has also started to apply capillary microbeam methods to the irradiation of intracellular organelles [99][100][101].…”