Characterization on deuterium retention in tungsten target using spatially resolved laser induced desorption-quadrupole mass spectroscopy. (12th October 2021)

• Record Type: Journal Article
• Authors: Lyu, Yan; Li, Cong; Wu, Ding; He, Zhonglin; Zhao, Dongye; Qiao, Li; Wang, Peng; Ding, Hongbin
• Is Part Of: Physica scripta. Volume 96:Number 12(2021)
• Publication Date: 2021-10-12
• Subjects: LID-QMS -- fuel retention -- spatial distribution -- quantitative analysis; Physics -- Periodicals; 530.05
• DOI: 10.1088/1402-4896/ac2c24
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: It is still challenging to achieve the quantitative analysis with a spatially resolved measurement for a non-uniform fuel retention in Plasma Facing Materials (PFMs). In this work, a long-pulse ( τ p ≈ 750 μ s) Laser Induced Desorption-Quadrupole Mass Spectroscopy (LID-QMS) has been developed as a diagnostic approach for characterizing inhomogeneous deuterium (D) retention in tungsten (W) target exposed to D plasma for ∼1 h with the total ion flux of 4.0 × 10 21 D/(m 2 s) at the substrate temperature of 400 K. The behavior of desorption of trapped D during LID was analyzed. 2D-distribution features of D retention in the exposed and shadowed areas of the W-target were investigated with a lateral resolution of about 650 μ m and depth resolution of approximately 175 μ m. The results show that the D retention is almost uniform along lateral dimension in the D plasma exposure area with an average fluence of (2.51 ± 0.40) × 10 20 D m −2, while the value in the shadow area is only (0.25 ± 0.04) × 10 20 D m −2 which is one order of magnitude smaller than that in the exposure region. In the depth dimension, about 86.5% of the retained D is desorbed by the first laser pulse, which indicates that the D-retention is mainly distributed in the region less than 6.6 μ m based on the diffusion length. The micro-structures of W target exposed to D plasma after the long-pulse laser irradiation present swelling, blistering as well as bubble-bursting, which might be attributed to the thermodynamic interaction due to the rapid release of D particles from bulk to surface of W target during LID.