Patent ID: 8136372

Claim:
A method of making a fused silica article, the method comprising the steps of: a. providing a fused silica boule, wherein the fused silica boule has been consolidated, and wherein the fused silica boule has a concentration of hydroxyl groups of less than about 100 ppm by weight; b. diffusing the deuterium into the fused silica boule at a predetermined temperature by: i. exposing the fused silica boule to at least one pulse of a first deuterium pressure, wherein each pulse has a predetermined duration time and the first deuterium pressure is greater than ambient pressure; and ii. exposing the fused silica boule to a second deuterium pressure immediately after each pulse for a second duration time, wherein the second deuterium pressure is less than the first deuterium pressure, wherein steps (i) and (ii) are repeated for a predetermined time period, wherein the predetermined time period is sufficient to load a region of the fused silica boule with a combined concentration of protium and deuterium, and wherein the deuterium is present in an amount that is greater than its natural isotopic abundance; and c. annealing the fused silica boule after diffusing the deuterium into the fused silica boule at a predetermined annealing temperature to form the fused silica article, wherein the fused silica article has a combined concentration of protium and deuterium in a range from about 1×10 16 molecules/cm 3 up to about 6×10 19 molecules/cm 3 , and wherein deuterium is present in a concentration that is greater than its natural isotopic abundance.