Considerations on hydrogen isotopes release from thin films by laser induced ablation and laser induced desorption techniques

In this paper, we studied the release of deuterium atoms from 1 & mu;m aluminum layers by Laser Induced Ablation and Laser Induced Desorption methods, using a 1053 nm laser source operating with 10 ns pulse duration and 1 kHz pulse repetition rate. The software control of the laser pulse energy successfully accomplished the transition from layer ablation to layer desorption. The layers have been produced by High Power Impulse Magnetron Sputtering technique on substrates with different surface properties.The amount of deuterium released from aluminum layers was evaluated by Quadrupole Mass Spectrometry after ablation respectively desorption of a small area of the sample exposed to the focused laser beam. The results were compared with the one obtained by Thermal Desorption Spectroscopy, which indicated a total amount of deuterium in the analyzed sample of about 2.6 x 1021 D at/m2. The mass spectra data revealed that 85% (2.2 x 1021 D at/m2) and 9% (0.2 x 1021 D at/m2) of total deuterium atoms released from the aluminum layer by Laser Induced Ablation and Laser Induced Desorption, respectively, were detected. The mathematical fitting of the experimental data indicated different laser fluences that boundary the desorption from ablation processes. Through analyses of the morphology of aluminum layer surfaces in connection with the substrate surface quality, the release of deuterium atoms by Laser Induced Ablation or Laser Induced Desorption processes can be identified.