Update on Roughening Work Jake Blanchard HAPL MWG

Update on Roughening Work Jake Blanchard HAPL MWG Fusion Technology Institute University of Wisconsin e-meeting – July 2003

Agenda • • • Update on Experiment Comparison Thoughts on Measuring Mass Loss Latest Temperature Predictions Initial Fracture Results Progress on Paper

Experiment Comparison Table Experiment Type Energy (ke. V) Max Fluence per Pulse (J/cm 2) Approx Depth of Energy (microns) Max Starting Temperature (C) RHEPP Ions 750 7 1 -10 600+ Z X-Rays 0. 8 -1. 2 3000 1 -2 1000 XAPPER X-Rays 0. 1 -0. 4 7 1 -2 RT+ UCSD Laser 0. 7 0 1000 Electra electrons 2 100 Infrared UW IEC Ions 500 100 q=10 MW/m 2 0 Flux=5 x 10^ 19 /m 2 -s 1

Experiment Comparison Table Experiment Max Sample Size (cm) Flat Top Rise Pulse Width Time (ns) Max Rep Rate (Hz) Max Sample Number Actively Cycles Cooled? RHEPP 100 NO Z 6 NO XAPPER 2. 5 diameter UCSD 1 cm x 1 cm 8 Electra 30 cm x 100 cm 100 Infrared UW IEC 30 -50 (FWHM) >10 ms 40 10 1 e 6 NO 10 3 e 5 NO 5 10 k/d YES NO

Data to Be Collected in Surface Exposure Experiments • BASICS – Name of Facility – Name of Experimentalist • DEPOSITION – – – Energy Deposition type Energy Spectrum Deposition Profile Fluence per Cycle Number of Cycles Pulse Width and Rise Time • TARGET – – – Initial Target Temperature Target Dimensions Is the target cooled? How? Target Material(s) Material Identifier (Code) Surface Cleaning Process • RESULTS – Surface Evaluation Before and After – Mass Loss – Temperature History

How to Measure Mass Loss • Weigh Samples before and After • Measure Remaining Thickness of Armor (Profilometry, Auger, RBS) • Measure What Comes Off (Spectrometry/RGA)

Latest Temperature Predictions Tcoolant=400 C, h=10, 000 W/m 2 K, steel thickness=3 mm Chamber radius (m) Xe Pressure (m. Torr) Target Yield (MJ) W Thickness (microns) Peak W temperature in 10 cycles (C) Peak Steel Temperature in 10 cycles (C) Steel Temperature Swing (C) 8. 5 10 400 50 3280 820 350 8. 5 0 154 50 1820 600 170 8. 5 10 154 50 1440 570 140 8. 5 0 154 100 1820 520 90 8. 5 10 154 100 1440 500 70 7. 5 0 154 50 2320 660 230 7. 5 10 154 50 1870 620 180 7. 5 20 154 50 1530 590 160 7. 5 0 154 100 2320 550 120 7. 5 10 154 100 1860 530 100 6. 5 0 154 50 3100 730 290 6. 5 10 154 50 2540 690 240 6. 5 20 154 50 2070 660 210 6. 5 0 154 100 3100 600 160 6. 5 10 154 100 2530 580 140 5. 5 10 154 50 3660 800 330

Fracture Mechanics Analysis of Tungsten Coating Crack tip stress intensities during thermal cycling calculated using ANSYS J-integral fracture mechanics algorithm Contact surface Crack depth Tungsten Crack tip Steel

Thermal Response of Structure Temperature Contours Near Surface at end of Pulse 6. 5 m chamber 154 MJ target No gas 50 microns W

Stresses Resulting from Thermal Cycle Stresses at Maximum Temperature Stresses After Cool Down MPa

Fracture Mechanics Analysis Results • Maximum stress intensities occur at end of cycle (when structure is cool). • Stress intensity decreases with increasing crack depth Stress Intensity vs. Crack Depth After One Thermal Cycle Transient Stress Intensity (30 mm Crack Depth)

Next Steps • What is effect of crack spacing? • What if crack reaches steel?

Paper Outline – My Chapter • 3 Armor (Blanchard) – 3. 1 Prompt threats: Expt and modeling of the response of armor candidates • 3. 1. 1 ablation; (Expts: Olson, Rank, Tanaka, Latkowski, Najmabadi. • Modeling: Wisc) • 3. 1. 2 roughening (Expts: Olson, Rank, Tanaka, Latkowski, Najmabadi. • Modeling: Ghoneim, Blanchard) • 3. 1. 3 sputtering (Expts ? Modeling: Lucas? ) • 3. 1. 4 Do we gain anything with EW? (Ghoneim, Raffray) – 3. 2 Long term threats: Expt and modeling of the response of armor candidates • 3. 2. 1 He retention ( EW: Ghoneim, Solid wall: Snead, Expts: Kulcinski) • 3. 2. 2 Modeling: thermo-mechanical fatigue long term effects (Blanchard, . ) 3. 2. 3 Expts: thermo-mechanical fatigue long term effects (Latkowski, Najmabadi, Raffray, Ghoneim, (SNL? ))