| 摘要 |
<p>PURPOSE: To provide an electron gun having a long service life as well as a microwave tube having a high performance by forming a cold cathode having a spherical electron emission surface, and further forming an electron beam of high current density and small ripple. CONSTITUTION: An electron emission zone formed out of a material having a low work function, or an electron emission zone having a micro cold cathode processed and formed via a focusing ion beam(FIB) passing the center of the radius of curvature of a spherical surface 2 or the neighborhood thereof, is formed on a spherical substrate 1, thereby forming a cold cathode 6. Then, an electron gun is formed out of the cathode 6 and a beam formation electrode 21 at cathode potential or a beam formation electrode at positive or negative potential on the basis of the cathode potential as reference, and an anode 22. Furthermore, a microwave tube is also formed by use of the electron gun.</p> |
