Mark Tillack, John Pulsifer, Joel Hollingsworth, S. S.

Harilal

Final Optic Fabrication, Testing and System Integration

HAPL Project MeetingSan Diego, CA

8-9 August 2006

With contributions from: Bill Goodman (Schafer Corp.), Hesham Khater

(LLNL), Colin Ophus and Dave Mitlin (U. Alberta)

1. Improved our simulation capability

• A KrF oscillator-amplifier configuration was installed and tested

• Sample scanning and auto shutdown were added

2. Expanded the database on Al coatings (toward end-of-life)

• More data were obtained on electroplated and e-coated mirrors

3. Developed techniques to fabricate larger optics

• CMP was tested for post-processing large-area high-quality surfaces

4. Performed component and system integration

• A substrate assessment was performed (Schafer)

• Neutron irradiation experiments were planned

5. Explored alternative mirror concepts

• 4” AlMo mirrors were fabricated in collaboration w/ LBNL and U. Alberta

1. Improved our simulation capability

• A KrF oscillator-amplifier configuration was installed and tested

• Sample scanning and auto shutdown were added

2. Expanded the database on Al coatings (toward end-of-life)

• More data were obtained on electroplated and e-coated mirrors

3. Developed techniques to fabricate larger optics

• CMP was tested for post-processing large-area high-quality surfaces

4. Performed component and system integration

• A substrate assessment was performed (Schafer)

• Neutron irradiation experiments were planned

5. Explored alternative mirror concepts

• 4” AlMo mirrors were fabricated in collaboration w/ LBNL and U. Alberta

1. Improved our simulation capability

• A KrF oscillator-amplifier configuration was installed and tested

• Sample scanning and auto shutdown were added

2. Expanded the database on Al coatings (toward end-of-life)

• More data were obtained on electroplated and e-coated mirrors

3. Developed techniques to fabricate larger optics

• CMP was tested for post-processing large-area high-quality surfaces

4. Performed component and system integration

• A substrate assessment was performed (Schafer)

• Neutron irradiation experiments were planned

5. Explored alternative mirror concepts

• 4” AlMo mirrors were fabricated in collaboration w/ LBNL and U. Alberta

1. Improved our simulation capability

• A KrF oscillator-amplifier configuration was installed and tested

• Sample scanning and auto shutdown were added

2. Expanded the database on Al coatings (toward end-of-life)

• More data were obtained on electroplated and e-coated mirrors

3. Developed techniques to fabricate larger optics

• CMP was tested for post-processing large-area high-quality surfaces

4. Performed component and system integration

• A substrate assessment was performed (Schafer)

• Neutron irradiation experiments were planned

5. Explored alternative mirror concepts

• 4” AlMo mirrors were fabricated in collaboration w/ LBNL and U. Alberta

1. Improved our simulation capability

• A KrF oscillator-amplifier configuration was installed and tested

• Sample scanning and auto shutdown were added

2. Expanded the database on Al coatings (toward end-of-life)

• More data were obtained on electroplated and e-coated mirrors

3. Developed techniques to fabricate larger optics

• CMP was tested for post-processing large-area high-quality surfaces

4. Performed component and system integration

• A substrate assessment was performed (Schafer)

• Neutron irradiation experiments were planned

5. Explored alternative mirror concepts

• 4” AlMo mirrors were fabricated in collaboration w/ LBNL and U. Alberta

Progress was made in 5 areas

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Control over beam characteristics required us to add an amplifier

Death by 1000 cuts: loss of energy in the Pockels cell was the final straw

polarizepulse slice300 mJ150 mJKD*P50 mJ15 mJCompex laser“pseudo-ISI”10 mJ35 mJ150 mJ

“Performance improvements to the UCSD mirror test facility using an oscillator - amplifier configuration”S. S. Harilal, J. Pulsifer and M. S. Tillack

Gain curve with 5-ns pulse, 20.5 kV Compex, 17 kV LPX

Performance is strongly dependent on HV and timing of both lasers (and Pockels cell)

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Good news and bad news

The good news: the gain curve results in profile smoothing

High LPX voltage amplifies residual output from the Pockels cell

The bad news: non-linear gain and jitter can distort the temporal profile

Jitter allows leakage from latter part of seed

Seed pulse

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Facility improvements are making life easier, and higher shot-counts possible

Automated shutdown enables higher PRF

External control of target position allows more data (better statistics)

No damage

Damage leading to shutdown

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We have a lot more data now on diamond-turned Alumiplate

“Laser-induced damage testing of metal mirrors: fluence-life data and surface analysis”J. Pulsifer, M. S. Tillack, J. Hollingsworth, L. Carlson

PRF effect

• PRF data are looking promising

lifetime

• Higher shot count data look worse (this may be the limit for Alumiplate) reproducibilit

y

• Facility improvements have made data more reproducible

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Grain size effects on pure Al are obscured by variations in fabrication

techniques

BachAlumiplat

e

Schafer

• Evaporative coating was attempted because smaller grains should result in a stronger surface (y= o ky/d1/2)

• All surfaces were diamond-turned

• Not all evaporative coatings have smaller grains, and the trend with grain size is not obvious

• Better control of fabrication processes is essential for continuation of this work

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CMP provides us a pathway to high-quality, large-aperture metal mirrors

“Fabrication techniques for Al and Al alloy optical coatings for the GIMM”J. Hollingsworth, J. Pulsifer and M. S. Tillack

• Uses a corrosive slurry with carefully passivated surface

• Significant advantages over SPDT:

– Less “invasive” (thinner coatings)

– Time depends on depth, not area

– History of semiconductor-level QC

<1 nm RMS, 15 nm pitsCabot

Microelectronics is supporting this work with substantial IR&D support

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A new alloy, AlMo was explored as a high-strength alternative to pure

Al

• 2-gun magnetron sputtered

• Thick (>5 m) specular coating obtained with no postprocessing

• Improved mechanical properties

• Reflectivity & conductivity?

Acknowledgements:Thanks to Tim Renk, SNLAVelomir Radmilovic, LBNLDave Mitlin, U. AlbertaColin Ophus, U. Alberta

Hall-Petch and solid solution hardening regime

Amorphous/nano-crystalline regime

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Al-16%Mo and Al-24%Mo were fabricated and tested

• Beautiful, specular thick film

Si substrateAlMo (16%)gradient from AlMo to pure AlAl capping layertAlMotAltgrad10 nm

100 nm5 m

Possible solution:

• Low conductivity and increased absorption: poor performance

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Candidate substrates were evaluated in preparation for radiation testing

(1 cm) and prototype (4”) development

“Candidate Mirror Technologies for the Grazing Incidence Metal Mirror”Bill Goodman (Schafer Corp.)

Candidates: Metrics:• Neutronic feasibility

– Neutron damage resistance

– Purity

• Manufacturability– Surface figure– Roughness– Coating adhesion– Cooling capability

• Industrial capability– Available database– R&D needs (risk)– Cost

• Carbon Based – C-C composite – Carbon fiber reinforced

• Silicon Carbide -SiC (polycrystalline) – Reaction bonded SiC (2-phase,

polycrystalline) -SiC (CVD, polycrystalline) -SiC foam core (CVD/CVI, polycrystalline)

• Silicon– Silicon foam core (CVD/CVI, polycrystalline)– Czochralski (single crystal)

• Aluminum & Alloys– AlBeMet® 162– Al 6061 foam

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Neutron irradiations are being planned

• A key issue for substrates is neutron-induced swelling

• We plan to test candidate substrates: SiC, Si, AlBeMet, Al-6061

• Include Al coatings to measure neutron-induced roughness

• Measure surface shape and roughness after irradiationsThree 22-day cycles 5.4 FPY dose

8 mmTest optic50 mm

Handling of activated specimens is a major concern. We are performing activation and dose calculations prior to exposure, and will measure dose rates after exposure

background level

Al-6061 after full exposure

• HFIR flux: >0.1 MeV: 1015

n/cm2/s>1 MeV: 6x1014

n/cm2/s• Power plant:

>0.1 MeV: ~1013 n/cm2/s

>1 MeV: ~1013 n/cm2/s

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Next-step goals for GIMM R&D

• Coating-substrate development

– Fabricate and test Al on C/Si and Al/Be composites

– Continue efforts on coating improvements

– Obtain 4” specimens from vendors

– Plan test campaigns at Mercury and Electra

• End-of-life testing

– Complete the facility improvements

– Perform further studies of rep-rate effects

– Acquire data to 108 shots

• Radiation damage testing

– Finish planning

– Obtain specimens

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