An electron exit window foil for use with a high performance electron beam generator operating in a corrosive environment is provided. The electron exit window foil comprises a sandwich structure having a film of Ti, a first layer of a material having a higher thermal conductivity than Ti, and a flexible second layer of a material being able to protect said film from said corrosive environment, wherein the second layer is facing the corrosive environment.

Disclosed is an electron beam emission device comprising a housing which defines a space in which electron beams are accelerated, and has an opening at the other side thereof through which the electron beams are emitted; a cathode which is disposed at one side in the housing, and emits the electrons; an anode which is positioned in the housing so as to be spaced apart from the cathode toward the other side, and accelerates the electrons emitted from the cathode; and an insulation holder which insulates a portion between the cathode and the housing, and fixes the cathode, wherein the cathode has a surface which faces the anode and is formed concavely to have a gradient, and a rim of the surface of the cathode, which has the gradient, is formed to be rounded.

Disclosed is an electron beam emission device comprising a housing which defines a space in which electron beams are accelerated, and has an opening at the other side thereof through which the electron beams are emitted; a cathode which is disposed at one side in the housing, and emits the electrons; an anode which is positioned in the housing so as to be spaced apart from the cathode toward the other side, and accelerates the electrons emitted from the cathode; and an insulation holder which insulates a portion between the cathode and the housing, and fixes the cathode, wherein the cathode has a surface which faces the anode and is formed concavely to have a gradient, and a rim of the surface of the cathode, which has the gradient, is formed to be rounded.