Dynamic deuterium retention properties of tungsten measured using laser-induced breakdown spectroscopy

Abstract

Dynamic deuterium (D) retention properties of tungsten (W) are investigated under steady-state D plasma exposure in the PISCES-A linear plasma device. In contrast to static retention, dynamic retention is quickly released from the material at the termination of the incident plasma flux, and thus in-operando laser-induced breakdown spectroscopy (LIBS) measurements have been conducted during steady-state D plasma exposure. A procedure is, first, established to extract the dynamic retention component from the in-operando LIBS D I 656.1 nm line intensity, which can contain contributions from dynamic and static retention as well as background D/D2 gas, excited by both steady-state and laser-induced plasmas. Using the developed procedure, the dynamic D retention in W is systematically examined while scanning the following plasma exposure parameters: incident ion energy, E i, sample temperature, T s, incident ion flux, Γi. No clear E i dependence is seen in the range of E i ∼ 45–175 eV, as expected from a small variation in the average implantation depth (∼3–6 nm) of D in W. The dynamic retention is found to monotonously decrease with increasing T s from 348 to 573 K, while the total static retention is reported to peak at T s ∼ 500–600 K. It is revealed that the dynamic retention linearly increases with increasing Γi, and then saturates at Γi ⩾ 0.75 × 1021 m−2 s−1. Possible physical mechanisms for the observed dependence of the dynamic retention on T s and Γi are discussed. Furthermore, sequential pure He, followed by pure D, plasma exposures show that the dynamic D retention is not strongly affected by He bubbles in the near-surface region.

Deuterium supersaturated surface layer in tungsten: ion energy dependence

“…with (D I/W I) Dy /(D I/W I) St ∼ 0.76 at E i ∼ 75 eV. Thus, D/W Dy ∼ 0.13, which is higher than D/W St ∼ 0.089 unlike the previous analysis in [4]. We should note that the dynamic retention component is considered to include weakly trapped D with a de-trapping energy less than 1 eV [5,6], in addition to solute D, as discussed in [4].…”

“…Such a thin surface layer saturated with D is often called a D supersaturated surface layer (DSSL). Because of its unique state, both experimental [2][3][4] and theoretical [5][6][7][8][9] work have been conducted in recent years to clarify its basic properties such as the DSSL thickness, ∆t DSSL , and the D retention in DSSLs, as well as its formation mechanism and condition.…”

“…In our previous work [4], in-operando/in-situ laser-induced breakdown spectroscopy (LIBS) measurements were performed during D plasma exposure of W in the PISCES-A linear plasma device to explore dynamic, as well as static, D retention in the near-surface region within the laser ablation depth of ∼350 nm. It was found that both dynamic and static D retention showed no E i dependence in a range of E i ∼ 45-175 eV.…”

Effect of Plane Mirrors Combined with Au-Nanoparticle Confinement on the Spectral Properties of Fe Plasma Induced by Laser-Induced Breakdown

“…The technology is simple in sample preparation, easy in operation, and comprehensive in elements detected. Laser-induced breakdown spectroscopy (LIBS) technology is widely used in material detection, 1 − 3 environmental monitoring, 4 − 7 gas composition analysis, 8 − 10 and other fields. 11 − 14 Traditional LIBS has the disadvantages of low detection sensitivity and high spectral line background noise.…”

“…The technology is simple in sample preparation, easy in operation, and comprehensive in elements detected. Laser-induced breakdown spectroscopy (LIBS) technology is widely used in material detection, − environmental monitoring, − gas composition analysis, − and other fields. − Traditional LIBS has the disadvantages of low detection sensitivity and high spectral line background noise. Therefore, many methods have been proposed to enhance spectral intensity and improve the sensitivity of LIBS systems, such as nanoparticle enhancement, increasing sample temperature, multipulse, and other methods.…”