IFE Final Optics Neutron Irradiation

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IFE Final Optics Neutron Irradiation

• Scott Willms
• With input from Jim Cobble (P-24), Terry
  Taddeucci, Steve Wender (LANSCE-3), D. Wayne
  Cooke, Kurt Sickafus, Mike Stevens, Robert
  Hanrahan, Kathleen Alexander (MST-8), and Stuart
  Maloy (AAA-TPO)
• Los Alamos National Laboratory
• Presented February 6, 2001
• At Naval Research Laboratory

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Task summary

• Purpose Determine the effect of fusion neutrons
  on the properties of IFE final optics
• FY01 deliverable Expose optics sample to
  neutrons and perform pre- and post-irradiation
  examination
• Funding requirement 300K

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Damage mechanisms

• E-prime
• Si.
• 250 nm
• Peroxy
• Si-O-O.
• 600 nm
• Non-bonding oxygen hole center
• Si-O.
• 630 nm

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Optical attenuation of fused silica fibers after
irradiations of 1.4 x 1021 and 1.1 x 1023 n/m2
lt1 ppm OH fiber
600-800 ppm OH fiber
--D.W. Cooke, B.L. Bennett, E.H. Farnum J. Nuc.
Materials 232, 214-218 (1996)
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Task steps

• Obtain samples
• Pre-irradiation characterization
• Irradiation
• Post-irradiation examination
• Effects mitigation, if needed, and re-examination
• Modeling

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Los Alamos Neutron Science Center
APT Materials Irradiation Isotope Production
Manuel Lujan Jr. Neutron Scattering Center
Proton Radiography
Proton Storage Ring
800-MeV Linear Accelerator
Weapons Neutron Research
Future IPF
Neutron Resonance Spectroscopy

LANSCE Visitors Center
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Irradiation

• WNR
• 1-600 MeV spectrum
• 2.5 x 1010 neutrons/m2/s
• 1 month -gt 6 x 1016 neutrons/m2
• DT Neutrons
• 14 MeV
• 8 x 1011 neutrons/m2/s at 10 cm
• 1 week -gt 5 x 1017 neutrons/m2
• Dose determination
• Room temperature

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Samples

• Materials
• Fused silica
• CaF2
• Reflective optics?
• Sizes
• Numbers
• Surface preparation
• Coatings

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Pre- and post-irradiation characterization

• Transmissive property measurements
• Ring-down reflectometer
• Optical spectroscopy (250-2000 nm)
• Single wavelength test?
• Other
• Other measurements
• Transmission electron spectroscopy (TEM)
• Electron spin resonance (ESR)
• Energy-filtered electron diffraction (EFED)
• Extended X-ray absorption fine structure (EXAFS)

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Further tasks

• Effects mitigation
• Annealing
• Optical bleaching
• Modeling
• Point defect models

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Task assignments
Task Lead
Task coordination Scott Willms (STB-FES)
Optics samples Steve Payne (LLNL) Mark Tillack (UCSD)
Neutron irradiation Terry Taddeucci (LANSCE-3)
Pre and Post irradiation examination Transmissive properties Other property measurements Modeling Wayne Cooke (MST-8) Ralph Berggren (P-24) Kurt Sickafus (MST-8)/ Stuart Maloy (AAA-TPO) Cooke/Sickafus/Maloy
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Task timeline