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Title: Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized δ-Pu

Abstract

The effects on the local structure due to self-irradiation damage of Ga stabilized δ-Pu stored at cryogenic temperatures have been examined using extended x-ray absorption fine structure (EXAFS) experiments. Extensive damage, seen as a loss of local order, was evident after 72 days of storage below 15 K. The effect was observed from both the Pu and the Ga sites, although less pronounced around Ga. Isochronal annealing was performed on this sample to study the annealing processes that occur between cryogenic and room temperature storage conditions, where damage is mostly reversed. Damage fractions at various points along the annealing curve have been determined using an amplitude-ratio method, a standard EXAFS fitting, and a spherical crystallite model, and provide information complementary to the previous electrical resistivity- and susceptibility-based isochronal annealing studies. The use of a spherical crystallite model accounts for the changes in EXAFS spectra using just two parameters, namely, the crystalline fraction and the particle radius. Altogether, these results are discussed in terms of changes to the local structure around Ga and Pu throughout the annealing process and highlight the unusual role of Ga in the behavior of the lowest temperature anneals.

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [4]; ORCiD logo [4]; ORCiD logo [4];  [5];  [5];  [5]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1313548
Report Number(s):
LLNL-JRNL-682498; LA-UR-16-20844
Journal ID: ISSN 0021-8979
Grant/Contract Number:
AC52-07NA27344; AC02-05CH11231; AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 3; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; extended X-ray absorption fine structure spectroscopy; electrical resistivity; crystal structure; computer modeling; magnetic annealing

Citation Formats

Olive, D. T., Booth, C. H., Wang, D. L., Bauer, E. D., Pugmire, A. L., Freibert, F. J., McCall, S. K., Wall, M. A., and Allen, P. G. Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized δ-Pu. United States: N. p., 2016. Web. doi:10.1063/1.4958856.
Olive, D. T., Booth, C. H., Wang, D. L., Bauer, E. D., Pugmire, A. L., Freibert, F. J., McCall, S. K., Wall, M. A., & Allen, P. G. Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized δ-Pu. United States. doi:10.1063/1.4958856.
Olive, D. T., Booth, C. H., Wang, D. L., Bauer, E. D., Pugmire, A. L., Freibert, F. J., McCall, S. K., Wall, M. A., and Allen, P. G. 2016. "Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized δ-Pu". United States. doi:10.1063/1.4958856. https://www.osti.gov/servlets/purl/1313548.
@article{osti_1313548,
title = {Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized δ-Pu},
author = {Olive, D. T. and Booth, C. H. and Wang, D. L. and Bauer, E. D. and Pugmire, A. L. and Freibert, F. J. and McCall, S. K. and Wall, M. A. and Allen, P. G.},
abstractNote = {The effects on the local structure due to self-irradiation damage of Ga stabilized δ-Pu stored at cryogenic temperatures have been examined using extended x-ray absorption fine structure (EXAFS) experiments. Extensive damage, seen as a loss of local order, was evident after 72 days of storage below 15 K. The effect was observed from both the Pu and the Ga sites, although less pronounced around Ga. Isochronal annealing was performed on this sample to study the annealing processes that occur between cryogenic and room temperature storage conditions, where damage is mostly reversed. Damage fractions at various points along the annealing curve have been determined using an amplitude-ratio method, a standard EXAFS fitting, and a spherical crystallite model, and provide information complementary to the previous electrical resistivity- and susceptibility-based isochronal annealing studies. The use of a spherical crystallite model accounts for the changes in EXAFS spectra using just two parameters, namely, the crystalline fraction and the particle radius. Altogether, these results are discussed in terms of changes to the local structure around Ga and Pu throughout the annealing process and highlight the unusual role of Ga in the behavior of the lowest temperature anneals.},
doi = {10.1063/1.4958856},
journal = {Journal of Applied Physics},
number = 3,
volume = 120,
place = {United States},
year = 2016,
month = 7
}

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  • The effects on the local structure due to self-irradiation damage of Ga stabilized δ-Pu stored at cryogenic temperatures have been examined using extended x-ray absorption fine structure (EXAFS) experiments. Extensive damage, seen as a loss of local order, was evident after 72 days of storage below 15 K. The effect was observed from both the Pu and the Ga sites, although less pronounced around Ga. Isochronal annealing was performed on this sample to study the annealing processes that occur between cryogenic and room temperature storage conditions, where damage is mostly reversed. Damage fractions at various points along the annealing curve havemore » been determined using an amplitude-ratio method, a standard EXAFS fitting, and a spherical crystallite model, and provide information complementary to the previous electrical resistivity- and susceptibility-based isochronal annealing studies. The use of a spherical crystallite model accounts for the changes in EXAFS spectra using just two parameters, namely, the crystalline fraction and the particle radius. Together, these results are discussed in terms of changes to the local structure around Ga and Pu throughout the annealing process and highlight the unusual role of Ga in the behavior of the lowest temperature anneals.« less
  • © 2016 Author(s). The effects on the local structure due to self-irradiation damage of Ga stabilized δ-Pu stored at cryogenic temperatures have been examined using extended x-ray absorption fine structure (EXAFS) experiments. Extensive damage, seen as a loss of local order, was evident after 72 days of storage below 15 K. The effect was observed from both the Pu and the Ga sites, although less pronounced around Ga. Isochronal annealing was performed on this sample to study the annealing processes that occur between cryogenic and room temperature storage conditions, where damage is mostly reversed. Damage fractions at various points alongmore » the annealing curve have been determined using an amplitude-ratio method, a standard EXAFS fitting, and a spherical crystallite model, and provide information complementary to the previous electrical resistivity- and susceptibility-based isochronal annealing studies. The use of a spherical crystallite model accounts for the changes in EXAFS spectra using just two parameters, namely, the crystalline fraction and the particle radius. Together, these results are discussed in terms of changes to the local structure around Ga and Pu throughout the annealing process and highlight the unusual role of Ga in the behavior of the lowest temperature anneals.« less
  • Cited by 2
  • Radiation-induced trapped charge densities in 45-nm radiation-hardened oxides are estimated via capacitance-voltage (C-V) and thermally stimulated current (TSC) techniques as functions of irradiation and/or isochronal anneal temperature. Reductions in trapped-hole charge were greater for {minus}10 V and 0 V isochronal anneals than for 10 V anneals. This is attributed to enhanced electron-hole dipole pairing during positive-bias anneal. Between 22 C and 125 C, the trapped electron charge increases for 10 V isochronal anneals, and is approximately constant for 0 V and {minus}10 V anneals. Interface-trap charge decreases for 0 V isochronal annealing above 80 C, and {+-}10 V annealing abovemore » 100 C. Elevated temperature irradiation at 10 V shows similar trends to 10 V isochronal anneals. Trapped-hole energy scales derived from C-V measurements for positive or zero bias isochronal anneals are found to be inaccurate, due to the different temperature dependencies of trapped-hole annealing and trapped-electron buildup. Refined estimates of trapped-hole attempt-to-escape frequency are obtained via TSC. Isochronal annealing and elevated temperature irradiation techniques generally cannot be used for hardness assurance testing unless the results are calibrated to the low-rate irradiation or long-term annealing response for a given technology.« less