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Rapid Growth of Very Large KDP and KD*P Crystals in Support of the National Ignition Facility.

DE200515013188

Publication Date	2000
Personal Author	Hawley-Fedder, R.; Robey, H.; Biesiada, T.; DeHaven, M.; Floyd, R.; Burnham, A.
Page Count	18
Abstract	The National Ignition Facility will require hundreds of very large single crystals (boules) of KDP and KD*P for the amplifier and frequency conversion optics. Rapid growth now routinely produces 250-300 kg boules of KDP. Technical hurdles overcome during the past year include inclusion formation and spurious nucleation. Areas of continued interest are control of asymmetry and aspect ratio. Variations in KDP concentration on the pm scale at the growing crystal steps can cause inclusions of growth solution. Microscopic investigations, hydrodynamic modeling, and theoretical modeling have been combined to provide a good mechanistic understanding of the formation of inclusions. Modifications to rotation regimes to improve hydrodynamics can eliminate or minimize the effects of these instability mechanisms, and can increase the inclusion-free growth rate by 20-40% over previously observed growth rates. Aspect ratio and boule asymmetry remains of great interest. Small changes in asymmetry can result in significant increases in maximum yields for boules of the same mass. Reasons for the observed changes in aspect ratio during growth will be presented, along with methods to control or influence aspect ratio and boule asymmetry.
Keywords	Potassium phosphates Crystals Laser fusion reactors Crystal growth Us National Ignition Facility Potassium dihydrogen phosphates
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200526

Rapid Growth of Very Large KDP and KD*P Crystals in Support of the National Ignition Facility.

Rapid Growth of Very Large KDP and KD*P Crystals in Support of the National Ignition Facility.
DE200515013188

Publication Date	2000
Personal Author	Hawley-Fedder, R.; Robey, H.; Biesiada, T.; DeHaven, M.; Floyd, R.; Burnham, A.
Page Count	18
Abstract	The National Ignition Facility will require hundreds of very large single crystals (boules) of KDP and KD*P for the amplifier and frequency conversion optics. Rapid growth now routinely produces 250-300 kg boules of KDP. Technical hurdles overcome during the past year include inclusion formation and spurious nucleation. Areas of continued interest are control of asymmetry and aspect ratio. Variations in KDP concentration on the pm scale at the growing crystal steps can cause inclusions of growth solution. Microscopic investigations, hydrodynamic modeling, and theoretical modeling have been combined to provide a good mechanistic understanding of the formation of inclusions. Modifications to rotation regimes to improve hydrodynamics can eliminate or minimize the effects of these instability mechanisms, and can increase the inclusion-free growth rate by 20-40% over previously observed growth rates. Aspect ratio and boule asymmetry remains of great interest. Small changes in asymmetry can result in significant increases in maximum yields for boules of the same mass. Reasons for the observed changes in aspect ratio during growth will be presented, along with methods to control or influence aspect ratio and boule asymmetry.
Keywords	Potassium phosphates Crystals Laser fusion reactors Crystal growth Us National Ignition Facility Potassium dihydrogen phosphates
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200526