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Title: Progress in Developing Novel Double-Shell Metal Targets Via Magnetron Sputtering

Abstract

Double shell inertial confinement fusion targets represent a unique platform for achieving ignition. They consist of a low-Z outer ablator, a high-Z inner pusher layer, and low density foam layer sandwiched in-between. There is the possibility that double shell targets may achieve ignition at lower ion temperatures due to the containment of radiation and conduction losses as well as requiring smaller convergence ratios. We have explored using magnetron sputtering to make the inner high-Z pusher layers and have demonstrated a W-Cr bilayer inner shell design. An Al-Be mixture was explored as one of the outer ablator materials. This material takes advantage of Al x-ray M-band absorption to reduce pre-heating and still retain Be high ablation speeds. Typical commercial Al-Be materials suffer from phase separation. However, by using magnetron sputtering we have been able to demonstrate homogeneous Al-Be ablator coatings. The sputtered material forms with nano-sized grains and has demonstrated excellent machinability. As a second type of shell explored, pushered single shells can exploit large density gradients to stabilize Rayleigh-Taylor instabilities during compression. Sharp gradients will have higher ignition yields and larger grading lengths will be more stable. We were able to demonstrate pushered single shells made from W-Be gradient layersmore » with various grading slopes and provide simulated results showing that the grading profiles can be influenced by the coating rates of two components.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [2];  [3];  [3]
  1. General Atomics, San Diego, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1481095
Report Number(s):
LLNL-JRNL-756109
Journal ID: ISSN 1536-1055; 939262
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 73; Journal Issue: 3; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Xu, H., Huang, H., Walker, J., Kong, C., Rice, N. G., Mauldin, M. P., Vocke, J. D., Bae, J. H., Sweet, W., Elsner, F. H., Farrell, M. P., Wang, Y. M., Alford, C., Cardenas, T., and Loomis, E. Progress in Developing Novel Double-Shell Metal Targets Via Magnetron Sputtering. United States: N. p., 2017. Web. doi:10.1080/15361055.2017.1387459.
Xu, H., Huang, H., Walker, J., Kong, C., Rice, N. G., Mauldin, M. P., Vocke, J. D., Bae, J. H., Sweet, W., Elsner, F. H., Farrell, M. P., Wang, Y. M., Alford, C., Cardenas, T., & Loomis, E. Progress in Developing Novel Double-Shell Metal Targets Via Magnetron Sputtering. United States. doi:10.1080/15361055.2017.1387459.
Xu, H., Huang, H., Walker, J., Kong, C., Rice, N. G., Mauldin, M. P., Vocke, J. D., Bae, J. H., Sweet, W., Elsner, F. H., Farrell, M. P., Wang, Y. M., Alford, C., Cardenas, T., and Loomis, E. Wed . "Progress in Developing Novel Double-Shell Metal Targets Via Magnetron Sputtering". United States. doi:10.1080/15361055.2017.1387459. https://www.osti.gov/servlets/purl/1481095.
@article{osti_1481095,
title = {Progress in Developing Novel Double-Shell Metal Targets Via Magnetron Sputtering},
author = {Xu, H. and Huang, H. and Walker, J. and Kong, C. and Rice, N. G. and Mauldin, M. P. and Vocke, J. D. and Bae, J. H. and Sweet, W. and Elsner, F. H. and Farrell, M. P. and Wang, Y. M. and Alford, C. and Cardenas, T. and Loomis, E.},
abstractNote = {Double shell inertial confinement fusion targets represent a unique platform for achieving ignition. They consist of a low-Z outer ablator, a high-Z inner pusher layer, and low density foam layer sandwiched in-between. There is the possibility that double shell targets may achieve ignition at lower ion temperatures due to the containment of radiation and conduction losses as well as requiring smaller convergence ratios. We have explored using magnetron sputtering to make the inner high-Z pusher layers and have demonstrated a W-Cr bilayer inner shell design. An Al-Be mixture was explored as one of the outer ablator materials. This material takes advantage of Al x-ray M-band absorption to reduce pre-heating and still retain Be high ablation speeds. Typical commercial Al-Be materials suffer from phase separation. However, by using magnetron sputtering we have been able to demonstrate homogeneous Al-Be ablator coatings. The sputtered material forms with nano-sized grains and has demonstrated excellent machinability. As a second type of shell explored, pushered single shells can exploit large density gradients to stabilize Rayleigh-Taylor instabilities during compression. Sharp gradients will have higher ignition yields and larger grading lengths will be more stable. We were able to demonstrate pushered single shells made from W-Be gradient layers with various grading slopes and provide simulated results showing that the grading profiles can be influenced by the coating rates of two components.},
doi = {10.1080/15361055.2017.1387459},
journal = {Fusion Science and Technology},
number = 3,
volume = 73,
place = {United States},
year = {2017},
month = {12}
}

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