Preparation of Target for Pulsed Neutron Generator by Impregnation of Deuterium in Evaporated Zirconium Film

Abstract

Thin D-Zr target for pulsed neutron generator of D-D reaction has been prepared by impregnation of deuterium gas in vacuum-deposited Zr film on Cu base. Cu bases used are made of OFHC, electrolytic Cu and electrolytic Cu pre-coated with thin Pt film by vacuum deposition. As similar sorption abilities for deuterium gas to Zr films deposited on these three kinds of bases, above materials seem to be suitable for the target base. The atomic ratio of deuterium to zirconium in the target has been determined as 11.5 (D/Zr).
Temperature of Cu base placed on the holder is kept under 100°C by water cooling for elimination of reactions between residual gases in the evaporator and Zr atoms deposited on the base during the deposition process.
Precautions should be payed for purity of deuterium gas introduced in the apparatus for impregnation. If active gases (H₂O, O₂ and N₂ etc.) are included in deuterium gas, Zr film reacts with these gases and amount of absorption of deuterium gas is markedly reduced.
Apparatus and methods used for preparation of target are illustrated. Discussions are also carried out on total amount and components of gases impregnated in target.