Influence of diamond turning and surface cleaning processes on the degradation of KDP crystal surfaces
One factor influencing the efficiency of KDP (potassium dihydrogen phosphate) frequency conversion arrays on the Nova laser system at LLNL has been environmental degradation, or fogging'', of the crystal surfaces. Decreases in array transmission by as much as 20% have been attributed to crystal fogging. The surfaces of the 27-cm square Nova array crystals are prepared by a wet diamond-turning process. The rate of surface fogging has been associated with several parameters of the diamond turning and subsequent cleaning processes. High humidity during diamond turning, storage, and use on the laser tends to accelerate the fogging. We suspect that some of the additives present in the diamond turning oil increase the fogging rate and have found a machining oil which minimizes this surface degradation. Efficient removal of the machining oils from the crystal surface also minimizes the fogging problem. Care must be taken to use cleaning solvents which do not cause additional surface degradation. The fogging rate is sensitive to the crystallographic orientation of the material as well as to surface roughness related to the diamond turning process. Accelerated fogging at diamond turning artifacts may increase crystal surface roughness causing increased beam modulation and scattering losses. 5 refs. 5 figs.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5487203
- Report Number(s):
- UCRL-JC-105835; CONF-9107115-7; ON: DE91015300
- Resource Relation:
- Conference: Society of Photo-Optical Instrumentation Engineers (SPIE) meeting, San Diego, CA (United States), 21-26 Jul 1991
- Country of Publication:
- United States
- Language:
- English
Similar Records
Processes for the elimination of fogging on KDP crystals prior to and during use in laser systems
Processes for the elimination of fogging on KDP crystals prior to and during use in laser systems
Related Subjects
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CRYSTALS
SURFACE PROPERTIES
SURFACE TREATMENTS
CLEANING
HUMIDITY
HYDROGEN COMPOUNDS
ICF DEVICES
MACHINING
NOVA FACILITY
POTASSIUM PHOSPHATES
ALKALI METAL COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
POTASSIUM COMPOUNDS
THERMONUCLEAR DEVICES
360604* - Materials- Corrosion
Erosion
& Degradation
360601 - Other Materials- Preparation & Manufacture
700208 - Fusion Power Plant Technology- Inertial Confinement Technology