Patent ID: 8404605

Claim:
A method of loading at least one fused silica article with a concentration of hydrogen that is within a concentration range having a maximum concentration of less than 1×10 17 molecules/cm 3 and a minimum concentration of about 0.4×10 17 molecules/cm 3 , the method comprising the steps of a. providing the at least one fused silica article, the fused silica article having a surface region and a center portion; b. heating the at least one fused silica article at a temperature in a range from about 400° C. up to about 500° C.; c. loading the at least one fused silica article at the temperature with an amount of hydrogen, such that the center portion of the at least one fused silica article exceeds the minimum concentration upon completion of loading the at least one fused silica article; d. removing hydrogen from the surface region of the fused silica article at the temperature, such that the fused silica article has an average hydrogen concentration that is less than the maximum concentration; and e. reloading the surface region at the temperature with hydrogen, such that the hydrogen concentration throughout the fused silica article is within the concentration range.