| 摘要 |
<p>A protection device comprising, coaxial to electron beam gun (2) in vacuum chamber (1), a diffuser (3) with its inlet opening facing the flow of the evaporated material, and a beam guide (7) whose outlet end is located inside the diffuser (3). On the outlet end-face of the diffuser (3) is mounted a cover (6) the side face of which features at least two openings (11, 12) of different size, the size of the larger opening being at least equal to that of the inlet opening of the diffuser (3). The surface area of the annular gap between the diffuser (3) and the beam guide (7) on plane (01) of its outlet end-face is not less than that of the inlet opening of the diffuser (3) and not greater than that of the larger opening (11) for forming the evaporated material flow above the welding bath.</p> |
