Update on Roughening Work

1
Update on Roughening Work

• Jake Blanchard
• HAPL MWG
• Fusion Technology Institute
• University of Wisconsin
• e-meeting July 2003

2
Agenda

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

3
Experiment Comparison Table
Experiment Type Energy (keV) Max Fluence per Pulse (J/cm2) 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 500 2 100
Infrared Infrared q10 MW/m2 0
UW IEC Ions 100 Flux5x1019 /m2-s 1
4
Experiment Comparison Table
Experiment Max Sample Size (cm) Flat Top Pulse Width (ns) Rise Time (ns) Max Rep Rate (Hz) Max Number Cycles Sample Actively Cooled?
RHEPP 100 NO
Z 6 NO
XAPPER 2.5 diameter 30-50 (FWHM) 10 1e6 NO
UCSD 1 cm x 1 cm 8 10 3e5 NO
Electra 30 cm x 100 cm 100 40 5 10k/d YES
Infrared gt10 ms YES
UW IEC NO
5
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

6
How to Measure Mass Loss

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

7
Latest Temperature Predictions
Tcoolant400 C, h10,000 W/m2K, steel thickness3
mm
Chamber radius (m) Xe Pressure (mTorr) 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
8
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
9
Thermal Response of Structure
Temperature Contours Near Surface at end of
Pulse 6.5 m chamber 154 MJ target No gas 50
microns W
10
Stresses Resulting from Thermal Cycle
Stresses at Maximum Temperature
Stresses After Cool Down
MPa
MPa
11
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)
12
Next Steps

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

13
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?))