Exposures of FW candidate materials on Z (x-rays - single shot) and on RHEPP (ions - 100s of shots)

Introduction

Craig Olson, Tina Tanaka, Tim Renk, Greg Rochau, Robert Peterson

HAPL Meeting at UCLA

June 2-3, 2004

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy’s National Nuclear Security Administration

under contract DE-AC04-94AL85000.

Philosophy of using x-rays on Z to test laser IFE dry-wall materials

Then: Use as single-shot test bed for initial screening of candidate wall materials, and compare with Bucky code calculations

Advantages: wide fluence range ( 1 J/cm2 to 1000 J/cm2)

very uniform fluence (large distance from “point source”)

~1 keV x-rays for tungsten wire array

tailored line radiation to 4 keV, and higher, if wanted

Disadvantages: debris, exact spectra, add-on shots hard to acquire

Now: Finalize understanding of roughening

Normalize results on Z with results on XAPPER

Test materials with many keV spectra (closest to threat spectra) if desired

Test “final” candidate material

Tungsten exposure to x-rays on Z shows that x-ray damage should not be a problem (single shot)

0

0.5

1

1.5

2

2.5

0.1 1 10 100

Fluence (J/cm2)

Mel

tin

g D

epth

threat threat(154 MJ) (400 MJ)

Philosophy of using ions on RHEPP to test laser IFE dry-wall materials

Then: Use as single-shot test bed for initial screening of candidate wall materials, and compare with Bucky code calculations

Advantages: power plant relevant ion fluences (up to ~10 J/cm2)

uniform fluence, choice of ions

effect of Bragg peak

easy access, fast turn around

Disadvantages: ~ 100 ns (whereas threat is ~ s)

Now: Principle facility for ion testing of candidate wall materials for HAPL

Extensive studies of ablation, roughening, cracking, valleys, exfoliation, etc.

Extensive studies of aging (above ~ 100 shots)

100s to 1000 or more shots

Extensive range of candidate materials are being tested

FW material exposure to ions on RHEPP shows that ion damage is still an issue

AblationDepth (m)

F(J/cm2)

Net AblationNo net ablation, but surface roughening

Threshold for ablation

Threshold for roughening

1.25 J/cm2

2 J/cm2

(current tests)

For W: 6 J/cm2

Threats: 154 MJ 400 MJ 8.5 J/cm2 21.1 J/cm2

(1.82 J/cm2) (4.54 J/cm2)