Electron gun arrangements having closely spaced cathode and electrode and a vacuum seal

摘要

An electron gun arrangement includes a cathode having a front surface and control grid located in front of it. The control grid is mounted via a cylindrical support on a Kovar mount. The cathode is supported by a cylindrical support mounted on a Kovar support. Ceramic material being located between the two supports. The vacuum envelope within which the electron gun is contained includes the Kovar support and a flexible member with which it makes a vacuum seal, this member being of copper. The copper member is sealed to a ceramic cylinder via metal flanges. The assembly permits the spacing between the cathode and grid to be maintained while the copper member permits thermal expansion to occur to maintain vacuum integrity.