Robin Miles

Rigorous surface enhanced Raman spectral characterization of large-area high-uniformity silver-coated tapered silica nanopillar arrays

Surface enhanced Raman spectroscopy (SERS) has been increasingly utilized as an analytical technique with significant chemical and biological applications (Qian et al 2008 Nat. Biotechnol. 26 83; Fujita et al 2009 J. Biomed. Opt. 14 024038; Chou et al 2008 Nano Lett.8 1729; Culha et al 2003 Anal. Chem. 75 6196; Willets K A 2009 Anal. Bioanal. Chem. 394 85; Han et al 2009 Anal. Bioanal. Chem. 394 1719; Sha et al 2008 J. Am. Chem. Soc. 130 17214). However, production of a robust, homogeneous and large-area SERS substrate with the same ultrahigh sensitivity and reproducibility still remains an important issue. Here, we describe a large-area ultrahigh-uniformity tapered silver nanopillar array made by laser interference lithography on the entire surface of a 6 inch wafer. Also presented is the rigorous optical characterization method of the tapered nanopillar substrate to accurately quantify the Raman enhancement factor, uniformity and repeatability. An average homogeneous enhancement factor of close to 10(8) was obtained for benzenethiol adsorbed on a silver-coated nanopillar substrate.

Timely Delivery of Laser Inertial Fusion Energy (LIFE)

Abstract The National Ignition Facility (NIF), the world’s largest and most energetic laser system, is now operational at Lawrence Livermore National Laboratory. A key goal of the NIF is to demonstrate fusion ignition for the first time in the laboratory. Its flexibility allows multiple target designs (both indirect and direct drive) to be fielded, offering substantial scope for optimization of a robust target design. In this paper we discuss an approach to generating gigawatt levels of electrical power from a laser-driven source of fusion neutrons based on these demonstration experiments. This “LIFE” concept enables rapid time-to-market for a commercial power plant, assuming success with ignition and a technology demonstration program that links directly to a facility design and construction project. The LIFE design makes use of recent advances in diode-pumped, solid-state laser technology. It adopts the paradigm of Line Replaceable Units utilized on the NIF to provide high levels of availability and maintainability and mitigate the need for advanced materials development. A demonstration LIFE plant based on these design principles is described, along with the areas of technology development required prior to plant construction.

Decontamination after a release of B. anthracis spores.

Decontaminating civilian facilities or large urban areas following an attack with Bacillus anthracis poses daunting challenges because of the lack of resources and proven technologies. Nevertheless, lessons learned from the 2001 cleanups together with advances derived from recent research have improved our understanding of what is required for effective decontamination. This article reviews current decontamination technologies appropriate for use in outdoor environments, on material surfaces, within large enclosed spaces, in water, and on waste contaminated with aerosolized B. anthracis spores.

Challenges Surrounding the Injection and Arrival of Targets at LIFE Fusion Chamber Center

Abstract IFE target designers must consider several engineering requirements in addition to the physics requirements for successful target implosion. These considerations include low target cost, high manufacturing throughput, the ability of the target to survive the injection into the fusion chamber and arrive in a condition and physical position consistent with proper laser-target interaction and ease of post-implosion debris removal. This article briefly describes these considerations for the Laser Inertial Fusion-based Energy (LIFE) targets currently being designed.

Nanolaminate Deformable Mirrors

The paper describes two similar deformable mirrors that will demonstrate the feasibility of nanolaminate-based deformable mirrors over a wide range of size scales. Two complementary technologies: high-spatial-density electrostatic actuators and thin, flexible, lightweight nanolaminate foils are combined. Electrostatic actuation of MEMS-like structures provides densely-spaced, repeatable deflections on the order of 10 mum. Nanolaminate foils provide a mirror surface that is simultaneously flexible enough to deform under electrostatic forces and tough enough to survive handling and bonding

Integration test of a miniature ExB mass spectrometer with a gas chromatograph for development of a low-cost, portable, chemical-detection system

Abstract We present preliminary test results for the integration of a miniature crossed electric and magnetic field mass spectrometer (MS) and a small commercial gas chromatograph (GC). We targeted the experiments to identify design variables for the next generation of field-portable low-cost micro-GC–MS instruments to be developed at Lawrence Livermore National Laboratory for identification of chemical warfare agents (CWAs) and, specifically, to evaluate the potential usage of the commercial version of the compact double-focusing MS (CDFMS) as the detector component.

Field-capable biodetection devices for homeland security missions

Biodetection instrumentation that is capable of functioning effectively outside the controlled laboratory environment is critical for the detection of health threats, and is a crucial technology for Health Security. Experience in bringing technologies from the basic research laboratory to integrated fieldable instruments suggests lessons for the engineering of these systems. This overview will cover several classes of such devices, with examples from systems developed for homeland security missions by Lawrence Livermore National Laboratory (LLNL). Recent trends suggest that front-end sample processing is becoming a critical performance-determining factor for many classes of fieldable biodetection devices. This paper introduces some results of a recent study that was undertaken to assess the requirements and potential technologies for next-generation integrated sample processing.

Autonomous system for pathogen detection and identification

The purpose of this project is to build a prototype instrument that will, running unattended, detect, identify, and quantify BW agents. In order to accomplish this, we have chosen to start with the worlds leading, proven assays for pathogens: surface-molecular recognition assays, such as antibody-based assays, implemented on a high-performance, identification (ID)-capable flow cytometer, and the polymerase chain reaction for nucleic-acid based assays. With these assays, we must integrate the capability to: (1) collect samples form aerosols, water, or surface; (2) perform sample preparation prior to the assays; (3) incubate the prepared samples, if necessary, for a period of time; (4) transport the prepared, incubated samples to the assays; (5) perform the assays; (6) interpret and report the result of the assays. Issues such as reliability, sensitivity and accuracy, quantify of consumables, maintenance schedule, etc. must be addressed satisfactorily to the end user. The highest possible sensitivity and specificity of the assay must be combined with no false alarms. Today, we have assays that can, in under 30 minutes, detect and identify simulants for BW agents at concentrations of a few hundred colony- forming units per ml of solution. If the bio-aerosol sampler of this system collects 1000 1/min and concentrates the respirable particles into 1 ml of solution with 70 percent processing efficiency over a period of 5 minutes, then this translates to a detection/ID capability of under 0.1 agent- containing particle/liter of air.

LIFE Tritium Processing: A Sustainable Solution For Closing The Fusion Fuel Cycle

Abstract The Laser Inertial Fusion Energy (LIFE) power plant is being designed to deliver a transformative source of safe, secure, sustainable electricity, in a time scale that is consistent with the global energy market needs. The LIFE market entry plant will demonstrate the feasibility of a closed fusion fuel cycle, including tritium breeding, extraction, processing, re-fueling, accountability and safety, in a steady-state power-producing device. While many fusion plant designs require large quantities of tritium for startup and operations, a range of design choices made for the LIFE fuel cycle act to reduce the inprocess tritium inventory. The high fractional burn-up (~30%) in an Inertial Fusion Energy (IFE) capsule relaxes the tritium breeding requirements, while the use of only milligram quantities of fuel per shot and choice of a pure lithium heat transfer fluid substantially reduce the amount of material entrained in the facility. Additionally, the high solubility of tritium in the lithium breeder is expected to mitigate the need for development of permeation barriers in the engine systems, normally required to control routine releases within the allowable regulatory limits. The present paper offers an overview of the design of the LIFE fuel cycle, including a summary of the technology development plan consistent with the delivery schedule of the LIFE market entry plant.

Large scale nanolaminate deformable mirror

This work concerns the development of a technology that uses Nanolaminate foils to form light-weight, deformable mirrors that are scalable over a wide range of mirror sizes. While MEMS-based deformable mirrors and spatial light modulators have considerably reduced the cost and increased the capabilities of adaptive optic systems, there has not been a way to utilize the advantages of lithography and batch-fabrication to produce large-scale deformable mirrors. This technology is made scalable by using fabrication techniques and lithography that are not limited to the sizes of conventional MEMS devices. Like many MEMS devices, these mirrors use parallel plate electrostatic actuators. This technology replicates that functionality by suspending a horizontal piece of nanolaminate foil over an electrode by electroplated nickel posts. This actuator is attached, with another post, to another nanolaminate foil that acts as the mirror surface. Most MEMS devices are produced with integrated circuit lithography techniques that are capable of very small line widths, but are not scalable to large sizes. This technology is very tolerant of lithography errors and can use coarser, printed circuit board lithography techniques that can be scaled to very large sizes. These mirrors use small, lithographically defined actuators and thin nanolaminate foils allowing them to produce deformations over a large area while minimizing weight. This paper will describe a staged program to develop this technology. First-principles models were developed to determine design parameters. Three stages of fabrication will be described starting with a 3x3 device using conventional metal foils and epoxy to a 10-across all-metal device with nanolaminate mirror surfaces.