1. X-ray Effects on Tungsten, Rhenium, and Tungsten Alloy Surfaces Results from Z machine T. J. Tanaka, T. J. Renk, G. A Rochau, and C. L. Olson Sandia National Laboratories* Presented April 4 & 5, 2002, San Diego CA *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 • Experimental configuration • Samples – W, W/Re, Re, W/La • SiC-Si, SiC, and PbLi results also reported as they were exposed since November • Results—Optical, Surface and Backscatter electron images • Conclusions • Future work Tanaka, IFE Meeting April 4,5 2002

3. Acknowlegements • Gordon Chandler and Bill Stygar who kindly allowed us to piggy-back on their Z shots • Steve Lazier and Z machine staff for MPRS box handling and alignment • Alice Kilgo–sample preparation • Liz Sorroche for use of Wyko surface analysis instrument Tanaka, IFE Meeting April 4,5 2002

4. Configuration in Z • Piggy back on tungsten-wire array Z shots • MPRS box in use • High collimation • Front aperture 50 cm from target • 4 samples per shot • Filters to approximate NRL target Tanaka, IFE Meeting April 4,5 2002

5. Fluence with various filters 2 mm Kimfol + .1 mm Al + 2.5 mm Be No Filter 2 mm Kimfol +.1 mm Al 2 mm Kimfol + .1 mm Al + 4.0 mm Be Tanaka, IFE Meeting April 4,5 2002

6. Samples Exposed Since November 2001 Tanaka, IFE Meeting April 4,5 2002

7. Results W 29 J/cm2 leads to slight weight loss, lower flux-no change Optical image Surface profile image Backscatter electron image Tanaka, IFE Meeting April 4,5 2002

8. Results Re The surface on Re changed for all levels of flux Optical image Backscatter electron image Surface image at 3.5 J/cm2 0.2 mm valleys Tanaka, IFE Meeting April 4,5 2002

9. Results W75%Re25% Surface at 29 J/cm2 shows grain structure, less flux shows little effect Optical Image Backscatter electron image Tanaka, IFE Meeting April 4,5 2002

10. Results W99%La1% Surface effect at 3.5 J/cm2, but lower flux, no effect* Optical Image *W99%/La1% was not exposed to 29 J/cm2. Samples from M. Tillack Tanaka, IFE Meeting April 4,5 2002

11. Results Si/C-Si RS420 and SiC* Step in SiC-Si, but none in SiC Optical image of SiC-Si Surface image of SiC-Si at 8 J/cm2 These samples were provided by Koichi Kasuya, Tokyo Institute of Technology. There is a question on the identification of these samples. Optical image of SiC Tanaka, IFE Meeting April 4,5 2002

12. Results PbLi Mass loss – 34 mg/cm2 Optical Image Surface image at 29 J/cm2 –2-5 mm loss Tanaka, IFE Meeting April 4,5 2002

13. Conclusions • Tungsten, Rhenium and Tungsten alloys were exposed to X-ray pulses from Z machine from 29 to 1.5 J/cm2 • Ablation does not occur uniformly, but has localized structure • Surface imaging (Wyko) and SEM are both needed to adequately determine effects of xrays on materials Tanaka, IFE Meeting April 4,5 2002

14. Future Work • W, Re, and W alloy samples • More SEM on top surfaces at higher magnification to match surface images • Cross section of samples will be imaged with SEM to obtain information on the melt layer • C and C composites • Graphite, MFC-1, and 2-d composites • Expose 4 samples per Z shot • Similar analysis as for W and Re above Tanaka, IFE Meeting April 4,5 2002