1. Schematic of the experimental apparatus
Incident energy and charge deposition dependences of electron transmission
through a microsized tapered glass capillary
S. J. Wickramarachchi1, T. Ikeda2, B. S. Dassanayake3, D. Keerthisinghe1, J. A. Tanis1
1 Department of Physics, Western Michigan University, Kalamazoo, MI 49008, USA
2 Atomic Physics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama , Japan
3 Department of Physics, Faculty of Science, University of Peradeniya, Sri Lanka
Introduction
The guiding of highly charged ions (HCIs) and electrons through insulating nanocapillary foils [1,2] and microsized glass capillaries has been investigated in recent years [3,4]
Microsized tapered glass capillaries have attracted attention because of their high focusing ability [5] and ability to produce high density charged ion beams [6]
Applications of tapered glass capillaries
High resolution x-ray imaging [7]
In-air PIXE analysis [8]
Nuclear Reaction Analysis [9]
Biological cell surgery [10]
Incident electron energies of 500 and 1000 eV on a tapered Borosilicate glass capillary were studied
The capillary had an inlet inner diameter of 800 µm and outlet diameter of 100 µm
The sample was prepared by the RIKEN laboratory in Japan and the measurements were conducted at Western Michigan University
Angular and charge deposition dependences of the transmitted intensities at 500 eV and 1000 eV were examined
e gun
= Tilt angle
 = Azimuthal Angle
θ = Observation angle
Spectrometer
For 500 eV, transmitted energy spectra have the energy width and centroid energy equal to those of incident beam, the transmission is elastic
For 1000 eV, inelastic nature of the energy spectra is clearly seen with the green and blue peaks giving evidence by broader energy width compare to the elastic red peak
Charge deposition dependence
500 eV (beam flux into capillary ~60 pA)
Transmission gradually increased (charge up constants ~65 nC)
Reaches relatively stable transmission with some oscillations
Elastic behavior dominant
1000 eV (beam flux into capillary ~25 pA)
Quicker charge up was observed (charge up constants ~ 3.5 nC)
Periodic oscillations were observed
For larger tilt angles stable transmission was observed
Both elastic and inelastic transmission contribute
References
[1] N. Stolterfoht et al., Phys. Rev. A 88, (2002)
[2] S. Das et al., Phys. Rev. A 76, (2007)
[3] T. Ikeda et al., J. Phys. Conf. Ser. 399, (2012)
[4] B. S. Dassanayake et al., Phys. Rev. A 81, (R) (2010)
[5] T. Nebiki et al., J. Vac. Sci. Technol. A 21, 1671 (2003)
[6] D. Sekiba et al., Nucl. Instr. and Meth. B 266, 2125 (2008)
[7] J. Hasegawa et al., Nucl. Instr. and Meth. B 266, 2125 (2008)
[8] T. Nebiki et al., Nucl. Instrum. Meth. Phys. Res. B 249, 226 (2006)
[9] D. Sekiba et al., Nucl. Instr. and Meth. B 266, 4027 (2008)
[10] Iwai et al., App. Phys. Lett. 92, (2008)
Three peak structure attributed to direct transmission and reflection from each wall
Energy dependence shows elastic transmission (Coulomb deflection) for 500 eV and inelastic transmission for 1000 eV
Charge dependence for 500 eV slowly increases for all angles investigated; for 1000 eV transmission almost immediately and oscillates for small angles and is nearly stable equilibrium for the larger angle.
Conclusion
Present Work
Schematic of the experimental apparatus
Electrons emitted from the e-gun were directed through the tapered glass capillary sample and analyzed by the spectrometer.  and θ are the tilt angle of the sample and observation angle, respectively
Angular dependence
500 eV
1000 eV
Energy dependence
Angular distributions for 500 eV and 1000 eV incident electrons for tilt angle ψ and spectrometer angle θ as indicated
Energy spectra for the maximum transmitted intensity positions indicated on angular spectra.
Beam flux into capillary  5 –15 pA
Electrons transmitted up to -6.5o for 500 eV and for 1000 eV
Beam intensity profiles had up to 3 peaks for both energies