The invention provides an end window
X ray tube, which comprises a casing, a
cathode filament used for transmitting
electron beams, a thin film
anode target and a berylium window. The
cathode filament is encapsulated in the casing, the berylium window is arranged on the end face of the casing and positioned in front of the
electron beam, the thin film
anode target is arranged between the
cathode filament and the berylium window, and the thin film
anode target are fixedly connected inside the casing. Simultaneously, the invention adopts the earthing of casing and the negative high-
voltage power supply mode of the cathode filament, and the casing which is electrically insulated and protected is avoided, thus being beneficial to the
radiation of the
X ray tube. The invention has the advantages that firstly, because
X ray is required to penetrate through a thin film anode, and the X
ray can emit from the end window, the low energy part of the X
ray is filtered and weakened, the
high energy part of the X
ray is influenced little, thereby an X ray spectrum with weaker background is obtained; secondly, a more complex
electric field is not required to control the deflection direction of an
electron, thus being beneficial to the product-forming and the
mass of the end window
X ray tube.