Materials Studies on Z
T. J. Tanaka, T. J. Renk, G. A Rochau, and C. L. Olson Sandia National Laboratories*
Dec. 5 and 6, 2002Naval Research Laboratory, Washington DC
*Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
Outline
• Results from last 6 months– W, W/Re, W/La2O3 Ion Beam Secondary Electron
Microscopy• Future work
– Z machine, heated samples– Fast closure valve on Z– Saturn-spectrum and yield– Materials
Fluence and Samples on ZFiltering Fluence SampleNo Filter 19 J/cm2 W, W/Re,
2 m Kimfol +.1 m Al
2.3 J/cm2 W, W/Re, W/LaO
2 m Kimfol + .1 m Al + 2.5m
Be
1.3 J/cm2 W, W/Re, W/LaO
2 m Kimfol + .1 m Al + 4.0 m Be
.98/cm2 W, W/Re, W/LaO
No Filter
2 m Kimfol +.1 m Al
2 m Kimfol + .1 m Al + 4.0 m Be
2 m Kimfol + .1 m Al + 2.5m Be
Ion Images W
Unexposed
Exposed to 19 J/cm2Exposed to 2.3 J/cm2
Exposed to 1.3 J/cm2
Pancake grains
Columnar grains
Platinum coating
DebrisCrater
Bottom of melted region
Ion images from Michael Rye and Joe Michael
A close look at debris craterW at 19 J/cm2
The crater bottom had traces of Fe, Ni and Cr. Surface must have been somewhat crystallized before impact of debris
Ion Images W75%Re25%
Exposed to 2.3 J/cm2 Exposed to 19 J/cm2
Exposed to 1.3 J/cm2Unexposed sampleColumnar grains
Pancake grains
Ion Images, W99%/La2O31% by Weight
Exposed to 2.3 J/cm2
Unexposed sample
Exposed to 1.3 J/cm2
Exposed to 0.98 J/cm2
Platinum coating
Depth of Molten Layer from FIB
Fluence (J/cm2)
Pure W W/25%Re W/1%La2O3
19 1.3 ± 0.1 m 1.2 ± 0.2 m No sample
2.3 0.4 ± 0.1 m 0.7 ± 0.2 m 1 ± 0.3 m
1.3 0 0 0
Using optical surface profiling, changes in the surface of the samples that melted were observed. The top surface was roughened at 19 and 2.3 J/cm2, but no obvious vaporization
Conclusions
• From C. Olson’s presentation, fluence levels that caused roughening in samples appear melted in ion cross-section images.
• Differences between W and W/25%Re include change in melting point and original grain size. These differences may account for discrepancy in apparent melt depth.
• Standard cross sectioning may be needed to view any
Future Work
• Sample preheat to 500 to 700 ° C• Debris mitigation with Fast closure valve• Saturn as a possibility for x-ray exposures• Material selection through Lance Snead, ORNL
Debris Mitigation with a Fast Shutter
Electromagnet or coil
PositionerAluminum Tube (Shutter)
Line of Sight
Catcher
•Electromagnetic shutter developed for Backlighter experiments on Z
•Shutter is in regular operation
•Modification of front collimator and material holder needed to provide correct collimation and heating of samples
Information from Dean Rovang
Saturn Spectrum and Yield
0100200300400500600700800900
2.5 3 3.5 4 4.5
Photon energy (KeV)
Inte
nsity
35-30 kJ of K-shell yield250 kJ ± 15% total yield
Information from Christine Coverdale
Saturn has less energy, is not used as much as Z, and costs less. Z produces more debris.