Testing of the Ti foil with TiN coating as an exit window of a pulsed electron accelerator

Abstract

Increasing the efficiency of electron beam extraction from a vacuum diode is an urgent problem for the practical use of accelerators. In the general case, the given problem is reduced to decreasing the mass thickness (g/cm2) of the exit window membrane while ensuring sufficient mechanical properties. The paper presents the results of testing an exit window 85 mm in diameter with a 25 μm Ti membrane and a 0.8 μm TiN coating. When tested, the coated membrane exhibited mechanical characteristics comparable to those of a 60 μm Ti membrane, which deteriorated upon repeated pumpings of the accelerator chamber volume due to the appearance of cracks in the coating. The energy loss of the electron beam in the exit window of the accelerator was decreased by 18%, as compared to the Ti 60 μm membrane. The use of a 25 μm Ti membrane with a 0.8 μm TiN coating provided 16 J per pulse energy output of more than 104 pulses of the electron beam (50–275 keV) with a repetition rate of 1–10 pulses per second. The obtained results will be used to further improve the electron beam extraction systems in the field of high-pressure applications.