High-Energy Molecular Beam Source Using a Non-diaphragm Type Small Shock Tube

  • Y. Yoshimoto
  • R. Aoyagi
  • N. Miyoshi
  • I. Kinefuchi
  • S. Takagi
  • Y. Matsumoto
Conference paper

Introduction

The molecular beam technique [1] is one of the powerful tools to analyze gassurface interactions. Various methods have been developed to generate the molecular beams with the translational energy of 1-several eV, which corresponds to the typical activation energy of surface reactions. Although seeded beams combined with a heated nozzle are often used, the heatproof temperature of the nozzle limits the beam energy.Arc-heated beams [2] have the energy ofmore than 1 eV. The problem is, however, that the beams contain copper atoms due to electrode erosion and thus contaminate surfaces. Several researchers also investigated shock-heated beam sources [3]. The replacement of a diaphragm and the long evacuation time between each shot, however, make the conventional shock-heated beam sources impractical for the scattering experiments of gas molecules on surfaces, since the scattering experiments require signal accumulation for a large number of beam pulses. In order to overcome these shortcomings, we have been developing a beam source using a nondiaphragm type small shock tube [4]. Our objective is to develop a shock-heated beam source which can generate the beams with the translational energy of more than 1 eV with high operating frequency. It is noteworthy that the inner diameter of our shock tube is a few millimeters, far smaller than that of conventional shock tubes. The volume reduction leads to the shorter evacuation time, which enables generating molecular beams with high operating frequency. On the other hand, it should be noted that the boundary layer has significant effects on shock propagation in small diameter tubes [5]. In addition, we developed a high-speed valve employing a current-loop mechanism [4] as a substitute for a diaphragm to reduce shock formation distance, which determines the tube length.

Keywords

Mach Number Shock Tube Straight Tube Translational Energy Beam Source 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Scoles, G.: Atomic and Molecular Beam Methods, 1st edn. Oxford University Press (1988)Google Scholar
  2. 2.
    Bickes, R.W., et al.: Utilization of an arc-heated jet for production of supersonic seeded beams of atomic nitrogen. Journal of Chemical Physics 64(9), 3648–3657 (1976)CrossRefGoogle Scholar
  3. 3.
    Peng, T.C., Liquornik, D.L.: Shock-Tube Molecular Beam for O at 3 eV. Review of Scientific Instruments 38(7), 989–991 (1967)CrossRefGoogle Scholar
  4. 4.
    Miyoshi, N., et al.: Development of Ultra Small Shock Tube for High Energy Molecular Beam Source. In: Abe, T. (ed.) Proceedings of the 26th International Symposium on Rarefied Gas Dynamics, pp. 557–562. American Institute of Physics, New York (2009)Google Scholar
  5. 5.
    Brouillette, M.: Shock waves at microscales. Shock Waves 13(1), 3–12 (2003)CrossRefGoogle Scholar
  6. 6.
    White, D.R.: Influence of diaphragm opening time on shock tube flows. Journal of Fluid Mechanics 4(6), 585–599 (1958)MATHCrossRefGoogle Scholar
  7. 7.
    Chisnell, R.F.: The motion of a shock wave in a channel, with applications to cylindrical and spherical shock waves. Journal of Fluid Mechanics 2(3), 286–298 (1957)MathSciNetMATHCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Y. Yoshimoto
    • 1
  • R. Aoyagi
    • 1
  • N. Miyoshi
    • 1
  • I. Kinefuchi
    • 1
  • S. Takagi
    • 1
  • Y. Matsumoto
    • 1
  1. 1.Department of Mechanical EngineeringThe University of TokyoBunkyo-kuJapan

Personalised recommendations