Fabrication of Graded Germanium-Doped CH Shells

Chen, K. C.; Cook, Robert; Huang, H.; Letts, Stephan A.; Nikroo, A.

doi:10.13182/fst06-a1196

Cited by 23 publications

(10 citation statements)

References 9 publications

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“…Current effort focuses on optimizing all of the steps and improving techniques for the precise assembly of both the fill tube to the capsule and the fill tube/capsule assembly into the hohlraum. In closing this section it should be noted that graded, Ge-doped CH designs exist and that capsules meeting these specifications have also been successfully fabricated (Chen et al, 2006(Chen et al, , 2007Theobald et al, 2007). We also note that good progress is being made on a high density carbon capsule via diamond chemical vapor deposition techniques (Biener et al, 2006).…”

Section: Figurementioning

confidence: 92%

“…The use of opaque Be shells became particularly attractive with the development of x-ray phase contrast characterization (Montgomery et al, 2004;Kozioziemski et al, 2007). Previous to this optical shadowography (Koch et al, 2000) was used, and this restricted layering research to transparent shells, typically CH shells (Chen et al, 2006), or polyimide shells . In addition to being able to characterize the fuel layer through optically opaque shells, the x-ray images are generally more representative of the surface roughness.…”

Section: D-t Fuel Layersmentioning

confidence: 99%

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National Ignition Facility target design and fabrication

et al. 2008

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The current capsule target design for the first ignition experiments at the NIF Facility beginning in 2009 will be a copper-doped beryllium capsule, roughly 2 mm in diameter with 160-µm walls. The capsule will have a 75-µm layer of solid DT on the inside surface, and the capsule will driven with x-rays generated from a gold/uranium cocktail hohlraum. The design specifications are extremely rigorous, particularly with respect to interfaces, which must be very smooth to inhibit Rayleigh-Taylor instability growth. This paper outlines the current design, and focuses on the challenges and advances in capsule fabrication and characterization; hohlraum fabrication, and D-T layering and characterization.2

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Section: Figurementioning

confidence: 92%

Section: D-t Fuel Layersmentioning

confidence: 99%

National Ignition Facility target design and fabrication

et al. 2008

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“…The current design 7 for the cryogenic capsule at hohlraum center is a graded Ge-doped 8,9 CH ablator of 918 lm inside radius and 190 lm shell thickness enclosing a 68 lm-thick layer of solid DT fuel initially held near the triple point. 10 A variety of hohlraum and capsule options [11][12][13] have been designed, spanning peak radiation temperatures between 270 and 310 eV, and using either Cu-doped Be, 14 Ge-doped CH, 15 or undoped or Mo-doped high density carbon 16 (HDC) capsules. A subset of these designs have a detailed set of target and laser parameter tolerances based on 1D, 2D, and 3D 17 sensitivity simulations.…”

Section: A Indirect-drive Designmentioning

confidence: 99%

Capsule implosion optimization during the indirect-drive National Ignition Campaign

et al. 2011

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Capsule performance optimization campaigns will be conducted at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition. The campaigns will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models using a variety of ignition capsule surrogates before proceeding to cryogenic-layered implosions and ignition experiments. The quantitative goals and technique options and down selections for the tuning campaigns are first explained. The computationally derived sensitivities to key laser and target parameters are compared to simple analytic models to gain further insight into the physics of the tuning techniques. The results of the validation of the tuning techniques at the OMEGA facility [J. M. Soures et al., Phys. Plasmas 3, 2108 (1996)] under scaled hohlraum and capsule conditions relevant to the ignition design are shown to meet the required sensitivity and accuracy. A roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget. Finally, we show how the tuning precision will be improved after a number of shots and iterations to meet an acceptable level of residual uncertainty.

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“…Graded doped CH-Ge capsules are being fabricated by plasma polymerization of trans-2-butene onto PAMS man-drels~Nikroo et al, 2006;Chen et al, 2006!. Ge dopant is placed into capsules by addition of Ge~CH 3 !…”

Section: Graded Doped Ch-gementioning

confidence: 99%

Status of the development of ignition capsules in the U.S. effort to achieve thermonuclear ignition on the national ignition facility

et al. 2006

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An important component of the U.S. effort to achieve thermonuclear ignition in 2010 on the National Ignition Facility is the development of high quality 2 mm diameter spherical capsules to function as the ablator and contain the cryogenic DT fuel. Three ignition capsule designs have been developed, and detailed fabrication specifications for each design have been established and placed under change control. A research program with activities coordinated mainly between Lawrence Livermore, General Atomics and Los Alamos is underway to demonstrate fabrication of capsules meeting specifications. The point design for ignition campaigns beginning in 2010 is a Cu-doped Be capsule that has a radial gradient in Cu dopant level in the capsule wall. This capsule is being produced by sputter deposition of Be and Cu onto either a hollow glow discharge polymer~GDP! spherical mandrel or a solid spherical mandrel, followed by removal of the mandrel and polishing of the capsule. A key goal in the U.S. is to demonstrate fabrication of this capsule by the end of 2006. Two other ignition capsule designs are also being developed as contingencies to the point design. One contingency design is a GDP capsule that has a radial Ge dopant level in its wall. This capsule is produced by co-deposition of Ge and GDP onto a PAMS mandrel followed by thermal removal of the mandrel. The second contingency design is a uniform Cu-doped Be capsule that is fabricated from high purity fine grain Be0.3at.%Cu alloy using a precision machining route followed by polishing. Ignition targets to be fielded in 2010 will be filled with DT fuel through a small fill hole. Laser drilling capability has been developed and used to drill approximately 5 mm diameter holes through capsule walls for DT filling. Characterization methods necessary for characterizing capsules are being developed.

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Fabrication of Graded Germanium-Doped CH Shells

Abstract: One of the current capsule designs for achieving ignition on the National Ignition Facility (NIF) is a 2 mm diameter graded Ge-doped

Cited by 23 publications

References 9 publications

National Ignition Facility target design and fabrication

National Ignition Facility target design and fabrication

Capsule implosion optimization during the indirect-drive National Ignition Campaign

Status of the development of ignition capsules in the U.S. effort to achieve thermonuclear ignition on the national ignition facility

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