A shield structure is provided that is suitable for use in connection with an x-ray device that includes an anode and cathode disposed in a vacuum enclosure in a spaced apart arrangement so that a target surface of the anode is positioned to receive electrons emitted by the cathode. The mentioned cationic surfactants and esterquats improve the conditioning and softening efficiency of non-ionic surfactants on natural and synthetic fibres so that the softening compositions obtained exhibit a high degree of efficiency in the treatment of fibres, such as textiles, paper and hair, and also facilitate ironing in the case of textile fibres and combing in the case of natural fibres. The fuel vapor collection canister includes a supply port and a discharge port. After the formation of the copper film, a treatment with hydrogen may be performed.