Publications

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The fabrication of ultra-thin lanthanum-doped lead zirconium titanate (PLZT) multilayer ceramic capacitors (MLCCs) using a high-power pulsed ion beam was studied. The deposition experiments were conducted on the RHEPP-1 facility at Sandia National Laboratories. The goal of this work was to increase the energy density of ceramic capacitors through the formation of a multilayer device with excellent materials properties, dielectric constant, and standoff voltage. For successful device construction, there are a number of challenging requirements including achieving correct stoichiometric and crystallographic composition of the deposited PLZT, as well as the creation of a defect free homogenous film. This report details some success in satisfying these requirements, although 900 C temperatures were necessary for PLZT perovskite phase formation. These temperatures were applied to a previously deposited multi-layer film which was then post-annealed to this temperature. The film exhibited mechanical distress attributable to differences in the coefficient of thermal expansion (CTE) of the various layers. This caused significant defects in the deposited films that led to shorts across devices. A follow-on single layer deposition without post-anneal produced smooth layers with good interface behavior, but without the perovskite phase formation. These issues will need to be addressed in order for ion beam deposited MLCCs to become a viable technology. It is possible that future in-situ heating during deposition may address both the CTE issue, and result in lowered processing temperatures, which in turn could raise the probability of successful MLCC formation.

The work documented in this report was undertaken as part of an ongoing investigation of innovative and potentially attractive value propositions for electricity storage by the United States Department of Energy (DOE) and Sandia National Laboratories (SNL) Electricity Storage Systems (ESS) Program. This study characterizes one especially attractive value proposition for modular electricity storage (MES): electric utility transmission and distribution (T&D) upgrade deferral. The T&D deferral benefit is characterized in detail. Also presented is a generalized framework for estimating the benefit. Other important and complementary (to T&D deferral) elements of possible value propositions involving MES are also characterized.

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National policymakers are currently considering a dilemma of critical importance to the continued security of the United States: how can U.S. nuclear weapons policies be leveraged to benefit U.S. nuclear nonproliferation goals in the near-term, without sacrificing U.S. national security? In its role supporting U.S. nuclear weapons policy, Sandia National Laboratories has a responsibility to provide objective technical advice to support policy deliberations on this question. However, to best fulfill this duty Sandia must have a broader understanding of the context of the problem. To help develop this understanding, this paper analyzes the two predominant analytical perspectives of international relations theory to explore their prescriptions for how nuclear weapons and nonproliferation policies interact. As lenses with which to view and make sense of the world, theories of international relations must play a crucial role in framing the trade-offs at the intersection of the nuclear weapons and nonproliferation policy domains. An analysis of what these theories suggest as courses of action to leverage nuclear weapons policies to benefit nonproliferation goals is then offered, with particular emphasis on where the policy prescriptions resulting from the respective theories align to offer near-term policy changes with broad theoretical support. These policy prescriptions are then compared to the 2001 Nuclear Posture Review to understand what the theories indicate policymakers may have gotten right in their dealing with the nuclear dilemma, and where they may have gone wrong. Finally, a brief international relations research agenda is proposed to help address the dilemma between nuclear deterrence and nuclear nonproliferation policies, with particular emphasis on how such an agenda can best support the needs of the policy community and a potential 'all things nuclear' policy deliberation and decision-support framework.

Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.

This report describes the results of a three-phase project that evaluated lead-based energy storage technologies for utility-scale applications and developed carbon materials to improve the performance of lead-based energy storage technologies. In Phase I, lead/carbon asymmetric capacitors were compared to other technologies that used the same or similar materials. At the end of Phase I (in 2005) it was found that lead/carbon asymmetric capacitors were not yet fully developed and optimized (cost/performance) to be a viable option for utility-scale applications. It was, however, determined that adding carbon to the negative electrode of a standard lead-acid battery showed promise for performance improvements that could be beneficial for use in utility-scale applications. In Phase II various carbon types were developed and evaluated in lead-acid batteries. Overall it was found that mesoporous activated carbon at low loadings and graphite at high loadings gave the best cycle performance in shallow PSoC cycling. Phase III studied cost/performance benefits for a specific utility application (frequency regulation) and the full details of this analysis are included as an appendix to this report.

We present the theory of operation along with detailed device designs and initial experimental results of a new class of uncooled thermal detectors. The detectors, termed microphotonic thermal detectors, are based on the thermo-optic effect in high quality factor (Q) micrometer-scale optical resonators. Microphotonic thermal detectors do not suffer from Johnson noise, do not require metallic connections to the sensing element, do not suffer from charge trapping effects, and have responsivities orders of magnitude larger than microbolometer-based thermal detectors. For these reasons, microphotonic thermal detectors have the potential to reach thermal phonon noise limited performance. © 2009 SPIE.

A combined photodarkening and thermal bleaching measurement of a large-mode-area (LMA) ytterbium-doped fiber (YDF) is presented. Photodarkened YDF sample is recovered to pre-photodarkened state by thermal annealing. As a result, this approach enables repeated measurements with the same sample and therefore eliminates uncertainties related to changing of the sample (such as sample length and splice losses). Additionally, our approach potentially improves the accuracy and repeatability of the photodarkening rate measurement, and also allows automation of the measurement procedure. © 2009 SPIE.