The density of hydrogen atoms supplied from hot tungsten (W) wires with a mesh structure to a tungsten phosphate glass plate substrate surface was evaluated. Variations in the hydrogen atom density were measured as a function of the mesh temperature (1000 to 1800 degrees C) and the exposure time (3 to 60 min). It became apparent that the quantity of H atoms supplied from hot W mesh was one order of magnitude larger than that supplied from hot W wires without a mesh structure, for the same temperature and surface area of the wire. (C) 2007 Elsevier B.V. All rights reserved.