Low-temperature growth of DKDP for improving laser-induced damage resistance at 350 nm

A set of twenty-three 20-L crystallizer runs exploring the importance of several engineering variables found that growth temperature is the most important variable controlling damage resistance of DKDP over the conditions investigated. Boules grown between 45 degreesC and room temperature have a 50% probability of 3 omega bulk damage that is 1.5 to 2 times higher than boules grown between 65 and 45 degreesC. This raises their damage resistance above the NIF tripler specification for 8 J/cm(2) operation by a comfortable margin. Solution impurity levels do not correlate with damage resistance for iron less than 200 ppb and aluminum less than 2000 ppb. The possibility that low growth temperatures could increase damage resistance in NIF-scale boules was tested by growing a large boule in a 1000-L crystallizer with a supplemental growth solution tank. four samples representing early and late pyramid and prism growth are very close to the specification as best it is understood at the present. Implications of low temperature growth for meeting absorbance, homogeneity, and other material specifications are discussed.