| 摘要 |
<p>PURPOSE:To contract an electron beam in a thin form even when its tip shape is changed due to heating during the use of it by using the hexaboride single crystal having a calcium hexaboride type crystal construction of the <111> orientation of the axial orientation of the needle-shaped hot cathode. CONSTITUTION:Hexaboride single crystal of a calcium hexaboride type crystal construction of the <111> axial orientation of the needle-shaped hot cathode is used in this cathode. For instance, the rod-shaped crystal of LaB6 0.15mm.square X several mm. in length having <111> axial orientation brought up by a flux method is point-welded to the tip of a hair pin made of Ta in 0.2mm.phi while processing the LaB6 crystal into the needle-shaped tip having the tip curvature about 1,000Angstrom by electrolytic polishing.</p> |
