Abstract: To protect the quartz of a quartz glass bulb (2) from attack by alkaline earth oxides emitted from electrodes (6) of the lamp, and prevent deterioration of the quartz in use of the lamp with respect to transmission of ultraviolet (UV) radiation, particularly in the short wave length range of 200 nm to 250 nm, boron silicate glass or glass-like aluminum oxide, or a mixture of boron silicate glass and glass-like aluminum oxide is interposed between the quartz bulb (2) and the electrodes. Boron oxide can be applied to the interior of the quartz bulb, and fired thereon to form, for example, a boron silicate glass layer (4) or diffuse into the quartz glass to form a diffusion layer (4') by suitable selection of firing temperatures. Alternatively, an aperture support element (35, 45) can retain a disk of boron silicate glass or glass-like aluminum oxide positioned between the electrodes and the quartz glass bulb.