News

Best Student Presentation Award at Division 2, the 2013 Fall meeting of the Physical Society of Japan (JPS)

• Date: Sep. 28, 2013
• Title:
  Investigation of Fuzz Formation on Tungsten Material under Noble-gas Irradiation by Binary-Collision-Approximation-based Simulation

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Context: A number of experiments show that helium plasma constructs filament (fuzz) structures whose diameter is in nanometer-scale on the tungsten material under helium plasma irradiation. However, The fuzz structure is not observed under other noble gas plasma irradiation except helium plasma [1]. In this paper, therefore, the penetration depth is investigated for helium (He), neon (Ne), and argon (Ar) gases by binary-collision-approximation-based (BCA) simulation [2] to reveal the possibility of fuzz formation under noble gas irradiation. BCA simulation is performed for two types of tungsten structure, i.e., amorphous and bcc crystalline structure. He, Ne, and Ar atoms are injected into these tungsten materials. Simulation result shows that He can penetrate to deeper position than Ne and Ar. It is also found that the sputtering threshold energy for He is higher than that of Ne and Ar. Therefore, it is concluded that the fuzz structure is more easily formed by He irradiation than that of Ne or Ar.

References: [1] M. Yajima, M. Yamagiwa, S. Kajita, N. Ohno, M. Tokitani, A. Takayama, S. Saito, A. M. Ito , H. Nakamura and N. Yoshida, “Comparison of Damages on Tungsten Surface Exposed to Noble Gas Plasmas”, J. Plasma Sci. Technol. 15(2013) 282 (5 pages). [2] S. Saito, A. M. Ito, A. Takayama and H. Nakamura, “Binary-Collision-Approximation-Based Simulation of Noble Gas Irradiation to Tungsten Materials”, J. Nucl. Mater. 438 (2013) S895-S898.