The study of the outgassing and retention features of helium in Al co-deposited layers by long-pulse laser combined with quadrupole mass spectroscopy.

In this work, the outgassing and deposition features of helium (He) in Al–He co-deposition layers have been studied using a long-pulse (τ ≈ 750 μs) laser combined with quadrupole mass spectroscopy (QMS) diagnostic approach. The He/Al co-deposited layers were prepared by pulse laser deposition. The spatially laterally-resolved measurements indicated that the co-deposited He is relatively homogeneous and can satisfy the need for laser parametric scanning. Laser-induced He outgassing behavior was studied under a series of heat flux factors (HFFs) spanning laser heating, melting and ablation and are used as a parameter to evaluate the transient heat load on the co-deposition layer. The outgassing behavior of He in co-deposited layer is strongly dependent on the temperature distribution. It was found that the slopes of the long pulse laser-induced He-outgassing curves in the melting and ablation stages are significantly less than that in the heating stage. Notably, the laser-induced He-outgassing features is also influenced by the He retention mechanism, which has been elaborated by comparing the experimental results with the thermal desorption spectroscopy (TDS). Laser induced complete melting or even ablation could completely release the He in the co-deposited layer and, noticeably, shows a weak correlation with its retention behavior, which is important for the accurate quantitative analysis and removal of D/He deposited under complicated conditions. • Long pulse laser combined with quadrupole mass spectroscopy was employed to investigate He retention in co-deposited layer. • Laser-induced He outgassing behavior was studied under a series of heat flux factors (HFFs) which span three stages of laser heating, melting and ablation. • The slopes of the long pulse laser-induced He-outgassing curves in the melting and ablation stages are significantly less than that in the heating stage. • The laser-induced He-outgassing features is also influenced by the He retention mechanism. • Laser induced complete melting or even ablation could completely release the He in the co-deposited layer and show a weak correlation with its retention behavior. [ABSTRACT FROM AUTHOR]