CONTAIMINATION PREVENTING DEVICE IN ELECTRON RAY DEVICE

摘要

PURPOSE:To prevent the contamination of an electron ray stop and a knife-edge for measuring the diameter of electron beams without any influence over electron beams, by heating the electron ray stop and the knife-edge. CONSTITUTION:A conductive heat insulator 5 for intercepting heat is interposed between an electron ray stop lens 3 and an electron ray stop 4. A semiconductive laser 6 is set on the inner wall of the end drum 9, and a portion of the electron ray stop 4 which is apt to be contaminated due to collision with electron beams is irradiated concentrically by laser beams 7 and heated. On the other hand, a conductive heat insulator 12 for intercepting heat is interposed between a Faraday cup 10 and a knife-edge 11, and a portion of the knife-edge 11 colliding with electron beams 1 is irradiated concentrically by laser beams from a semiconductor laser 13 and heated.