AVS 53rd International Symposium
    Thin Film Wednesday Sessions
       Session TF-WeM

Paper TF-WeM10
B doped Be Coatings for NIF Target Development

Wednesday, November 15, 2006, 11:00 am, Room 2022

Session: Thin Films for Photovoltaics and Energy Applications
Presenter: H. Xu, General Atomics
Authors: H. Xu, General Atomics
K. Moreno, General Atomics
K. Youngblood, General Atomics
A. Nikroo, General Atomics
J. Cooley, Los Alamos National Laboratory
C. Alford, Lawrence Livermore National Laboratory
S. Letts, Lawrence Livermore National Laboratory
A.V. Hamza, Lawrence Livermore National Laboratory
T. van Buuren, Lawrence Livermore National Laboratory
Correspondent: Click to Email
Sputtered beryllium and copper-doped beryllium coatings as thick as 170 µm have been deposited on spherical substrates to produce hollow shells that are required as targets for inertial fusion experiments.@footnote 1@ Be coatings by magnetron sputtering have achieved ~93-95 percent bulk density consistently up to 170 µm in thickness. Coatings on the spherical substrates exhibit columnar structure through the entire thickness. Transmission Electron Microscopy (TEM) indicates the presence of sub-micron voids mainly aggregated along the columnar structure and grain boundaries as well as some intra-granular voids. Ultra Small Angle X-ray Scattering (USAXS) was used to determine the size and distribution of pores within the coatings, which correlated well with the TEM data. Holes drilled in beryllium shells produced in this manner allow filling with the fusion fuel. Gas retention of these shells has been examined using mass spectrometry. It appears that a fraction of the pores in the coatings are interconnected, which leads to leakage in the hollow shells. Boron-doped Be layers at concentrations of ~5-20 atomic percent near the eutectic phase have been added to the Be shells. The addition of these layers has led to a significant improvement in D@sub 2@ gas retention of shells. However there remains a considerable scatter in the measured leakage. @FootnoteText@ @footnote 1@S. Haan et al., Phys. Plasma 2 (1995) 2480.