1. Exposures of Candidate First Wall Materials
C.L. Olson, T.J. Tanaka, T.J. Renk, G.A. Rochau
Sandia National Laboratories, Albuquerque, NM
R.R. Peterson
Los Alamos National Laboratory, Los Alamos, NM &
University of Wisconsin, Madison, Wisconsin
HAPL Program Workshop
University of Wisconsin
Madison, Wisconsin
September 24-25, 2003
Supported by NRL by the HAPL program by DOE NNSA DP
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. Regimes of FW Materials Response Studies for x-rays and ions
Ablation
Depth
(mm)
Net Ablation
No net ablation, but
surface roughening
F(J/cm2)
Threshold for roughening
Threshold for
ablation
Goal is to find and understand roughening threshold

3. Strategy for use of RHEPP and Z to test FW materials
Ion fluence for HAPL dry wall is an issue - present emphasis is to use ion beams on RHEPP (many shots) for extensive testing, and modeling with Bucky:
test roughening phenomena in heated samples on RHEPP (many shots)
examine potential mechanisms for roughening:
surface stress/yield at below melt temperatures,
strain-rate and grain size effects, etc.
establish threshold for roughening
X-ray fluence for HAPL dry wall does not appear to be an issue - but needs to be verified on Z
use RHEPP/Bucky results to narrow list of candidate materials
test best candidate materials on Z to verify threshold for roughening
heater for 1000° C, new filtered Z spectra, schedule for HAPL shots
on Z is all ready (next vu-graphs)

4. Layout for HAPL experiments on Z
Peak Diode Emission Temps
Sample Field of View
17.8 cm
Pinch Aperture
3mm tall x 8mm wide
Shielding Box
Z-Pinch
Heater
~ 1000 C
51.2 cm
63.3 cm

5. Z-machine sample heater
Heater with sample holder clips and thermocouple
Temperatures up to 1200°C
1 cm test diameter
4 samples/shot
Fluence levels: 1 J/cm2 and up

6. Time-integrated spectrum on sample with
Calculated Z Spectrum for Nov. HAPL Experiments
Time-integrated spectrum on sample with
8 mm Be + 1 mm CH filter
<E> ~ 1100 eV
F ~ 1 J/cm2
X-ray fluence at sample location is very uniform and  1 keV

7. Z Shot Schedule
HAPL add-on shots
HAPL add-on shots

8. Next Talks RHEPP experiments of candidate materials - Tim Renk
extensive list of materials tested (heated, many shots)
(various forms of W; W25Re; Re; Cu; CFC Graphite;
foams; C-C-W velvet; etc.)
extensive list of results (effects of grain structure; ion species
dependent roughening; deep-lying cracking; some samples
unexpectedly survive amazingly well)
BUCKY simulations of tungsten RHEPP experiments - Bob Peterson
effects of initial sample temperature
effects of ion species
stress/yield effects for surface temperatures below melting