Abstract: A hot-cathode X-ray tube having an end-mounted anode and a low energy consumption, including a filament, an anode in the form of a plate orientated perpendicularly to the electron beam which is emitted by the filament, an annular auxiliary electrode having a central opening and forming a diaphragm for the electron beam and a secondary anode for back scattered electrons. The anode and the diaphragm are made from the same metal selected from silver, rhodium, copper and molybdenum and at least the portions of the secondary anode facing the primary one are coated with the same metal.The tube may be used as a source of quasi-monochromatic radiation in apparatus for spectrometry by X-ray fluorescence, diffractometry and microradiography.