1. Materials Studies on Z T. J. Tanaka, T. J. Renk, G. A Rochau, and C. L. Olson Sandia National Laboratories* Dec. 5 and 6, 2002 Naval 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.

2. Outline Results from last 6 months –W, W/Re, W/La 2 O 3 Ion Beam Secondary Electron Microscopy Future work –Z machine, heated samples –Fast closure valve on Z –Saturn-spectrum and yield –Materials

3. Fluence and Samples on Z FilteringFluenceSample No Filter19 J/cm 2 W, W/Re, 2  m Kimfol +.1  m Al 2.3 J/cm 2 W, W/Re, W/LaO 2  m Kimfol +.1  m Al + 2.5  m Be 1.3 J/cm 2 W, W/Re, W/LaO 2  m Kimfol +.1  m Al + 4.0  m Be.98/cm 2 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 + 2.5  m Be

4. Ion Images W Unexposed Exposed to 19 J/cm 2 Exposed to 2.3 J/cm 2 Exposed to 1.3 J/cm 2 Pancake grains Columnar grains Platinum coating Debris Crater Bottom of melted region Ion images from Michael Rye and Joe Michael

5. A close look at debris crater W at 19 J/cm2 The crater bottom had traces of Fe, Ni and Cr. Surface must have been somewhat crystallized before impact of debris

6. Ion Images W75%Re25% Exposed to 2.3 J/cm 2 Exposed to 19 J/cm 2 Exposed to 1.3 J/cm 2 Unexposed sample Columnar grains Pancake grains

7. Ion Images, W99%/La 2 O 3 1% by Weight Exposed to 2.3 J/cm 2 Unexposed sample Exposed to 1.3 J/cm 2 Exposed to 0.98 J/cm 2 Platinum coating

8. Depth of Molten Layer from FIB Fluence (J/cm 2 ) Pure WW/25%ReW/1%La 2 O 3 19 1.3 ± 0.1  m1.2 ± 0.2  m No sample 2.3 0.4 ± 0.1  m0.7 ± 0.2  m1 ± 0.3  m 1.3000 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/cm 2, but no obvious vaporization

9. 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

10. 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

11. Debris Mitigation with a Fast Shutter Electromagnet or coil Positioner Aluminum 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

12. Saturn Spectrum and Yield 35-30 kJ of K-shell yield 250 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.