Dependence of the reliability of discharge radiation sources on the structural perfection of sapphire envelopes

The factors that determine the reliability of a discharge radiation source are considered. It is shown that the disorientation of blocks and the wall thickness influence the strength sapphire of envelopes. The temperature dependence of the limiting fracture stress of a sapphire tube is studied. The correlation between the curves of the ultimate values of the mechanical strength and the electric power per unit surface of a discharge bulb as a function of the number of blocks of a crystal is revealed. The general technical requirements for corundum tubes used as discharge-lamp envelopes are formulated.