Interaction of Li-D Films with Water Vapor

AbstractIn this work we investigated co-deposition of lithium-deuterium (Li-D) films in magnetron discharge and interaction of deposited films with water vapor. It was demonstrated that even at room temperature interaction with water vapor led to release of a large portion of deuterium from the deposited layers. After 30minutes exposure at the pressure about 10−1 Pa the main part of deuterium released from the sample and a characteristic peak for deuterium desorption from lithium films completely disappeared

Assessment of laser induced breakdown spectroscopy accuracy for determination of hydrogen accumulation in tungsten

Laser-induced breakdown spectroscopy (LIBS) is an in situ method of determining hydrogen (H) content in plasma-facing materials in tokamak fusion reactors. Observing radiation from the plasma plume produced by a powerful laser pulse during the target exposition characterizes the sample composition. This is typically accomplished using the Saha-Boltzmann (SB) plot technique under local thermodynamic equilibrium (LTE) conditions. Despite many experimental studies dedicated to applying LIBS to determine H isotope retention in fusion reactor materials, the current understanding of this method’s intrinsic accuracy remains inadequate. In this report, we use numerical calculations to estimate the relative error of determining H content in a sample using LIBS. As an example. we consider LIBS to study a W sample loaded with H in a vacuum. Under typical LIBS pulse parameters (109 W/cm2 and 12 ns duration), the error can be quite large, approximately 70%. We demonstrate that the error tends to decrease as the laser pulse intensity increases. Various factors contributing to the relative error are examined and their dependence on the LIBS plasma parameters is discussed. The SB plot remains a straight line even when LTE conditions are violated, making it difficult to anticipate the experimental results’ error