A procedure and the equipment necessary for single-point diamond flycutting (loosely referred to as diamond turning) potassium di-hydrogen phosphate (KDP) crystals are described. It is based on current KDP diamond turning activities at the Lawrence Livermore National Laboratory (LLNL), drawing upon knowledge from the Nova crystal finishing development during the 1980`s and incorporating refinements from our efforts during 1995. In addition to describing a step-by-step process for diamond turning KDP, specific discussions are included on the necessary diamond tool geometry and edge sharpness, cutting fluid, and crystal preparation, handling, cleaning, and inspection. The authors presuppose that the reader is already familiar with diamond turning practices.

Optical damage that results in large scale fracture has been observed in the large, high-fluence, fused-silica, spatial filter lenses on the Nova and Beamlet lasers. In nearly all cases damage occurs on the vacuum side of the lenses and because the vacuum side of the lens is under tensile stress this damage can lead to catastrophic crack growth if the flaw (damage) size exceeds the critical flaw size for SiO{sub 2}. The damaged 52 cm Nova lenses fracture into two and sometimes three large pieces. Although under full vacuum load at the time they fracture, the Nova lenses do not implode. Rather the authors have observed that the pieces lock together and air slowly leaks into the vacuum spatial filter housing through the lens cracks. The Beamlet lenses have a larger aspect ratio and peak tensile stress than Nova. The peak tensile stress at the center of the output surface of the Beamlet lens is 1,490 psi versus 810 psi for Nova. During a recent Beamlet high energy shot, a damage spot on the lens grew to the critical flaw size and the lens imploded. Post shot data indicate the lens probably fractured into 5 to 7 pieces, however, unlike …

Reflections from lens surfaces create parasitic beams that can damage optics in high-powered laser systems. These parasitic beams are low in energy initially, because of the low reflectivity of antireflection (AR) coated lens surfaces and because they are clipped by spatial filter pinholes, but subsequent amplification can raise them to damage fluence levels. Also, some of the pencil beams in multipass laser systems become pre-pulses at the output by by-pass one of more of the passes, arriving at the output ahead of the main pulse in time. They are insidious because pencil beams that are not initially a problem can become so due to a slow degradation of the AR coatings. Both the Nova and Beamlet laser systems at LLNL have had optics damaged by pencil beams. The best solution for pencil beams is to tip the lenses far enough to eliminate them altogether. This will be the approach taken for the National Ignition Facility (NIF).

The proposed National Ignition Facility is a 192 beam Nd:glass laser system capable of driving targets to fusion ignition by the year 2005. A key factor in the flexibility and performance of the laser is a front-end system which provides a precisely formatted beam to each beamline. Each of the injected beams has individually controlled energy, temporal pulseshape, and spatial shape to accommodate beamline-to-beamline variations in gain and saturation. This flexibility also gives target designers the options for precisely controlling the drive to different areas of the target. The design of the Front-End laser is described, and initial results are discussed.

The tolerance of the circuit topology proposed for the National Ignition Facility (NIF) power conditioning system to specific fault conditions is investigated. A new pulsed power circuit is proposed for the NIF which is simpler and less expensive than previous ICF systems. The inherent fault modes of the new circuit are different from the conventional approach, and must be understood to ensure adequate NIF system reliability. A test-bed which simulates the NIF capacitor module design was constructed to study the circuit design. Measurements from test-bed experiments with induced faults are compared with results from a detailed circuit model. The model is validated by the measurements and used to predict the behavior of the actual NIF module during faults. The model can be used to optimize fault tolerance of the NIF module through an appropriate distribution of circuit inductance and resistance. The experimental and modeling results are presented, and fault performance is compared with the ratings of pulsed power components. Areas are identified which require additional investigation.

LLNL plans to specify optical components for the National Ignition Facility according to ISO 10110, the new international standard for preparation of optics drawings. The standards have been approved by the international optics community and represent a fairly comprehensive language for describing optical components. We will describe our plan for implementation and experience to date in doing so.

In a plasma-electrode Pockels cell (PEPC), plasma discharges serve as transparent electrodes on each side of, an electrooptic crystal such as KDP. These plasmas facilitate rapid and uniform charging and discharging of the crystal. The authors describe PEPC technology deployed on Beamlet and envisioned for the National Ignition Facility. Performance on Beamlet is discussed in detail. They also discuss models which have shed light on PEPC operation. These models describe both the high-voltage sheath that forms near the crystal surface and the characteristics of the bulk plasma column.

It has been known that significant advances in electrochemistry really depend on improvements in the sensitivity, selectivity, convenience, and/or economy of working electrodes, especially through the development of new working electrode materials. The advancement of solid state chemistry and materials science makes it possible to provide the materials which may be required as satisfactory electrode materials. The combination of solid state techniques with electrochemistry expands the applications of solid state materials and leads to the improvement of electrocatalysis. The study of Ru-Ti{sub 4}O{sub 7} and Pt-Ti{sub 4}O{sub 7} microelectrode arrays as introduced in paper 1 and paper 4, respectively, focuses on their synthesis and characterization. The synthesis is described by high temperature techniques for Ru or Pt microelectrode arrays within a conductive Ti{sub 4}O{sub 7} ceramic matrix. The characterization is based on the data obtained by x-ray diffractometry, scanning electron microscopy, voltammetry and amperometry. These microelectrode arrays show significant enhancement in current densities in comparison to solid Ru and Pt electrodes. Electrocatalysis at pyrochlore oxide Bi{sub 2}Ru{sub 2}O{sub 7.3} and Bi{sub 2}Ir{sub 2}O{sub 7} electrodes are described in paper 2 and paper 3, respectively. Details are reported for the synthesis and characterization of composite Bi{sub 2}Ru{sub 2}O{sub 7.3} electrodes. Voltammetric …

The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage …

The Oklahoma Geological Survey (OGS), the Geological Information Systems department, and the School of Petroleum and Geological Engineering at the University of Oklahoma are engaging in a program to identify and address Oklahoma`s oil recovery opportunities in fluvial-dominated deltaic (FDD) reservoirs. This program includes the systematic and comprehensive collection and evaluation of information on all of Oklahoma`s FDD reservoirs and the recovery technologies that have been (or could be) applied to those reservoirs with commercial success. This data collection and evaluation effort will be the foundation for an aggressive, multifaceted technology transfer program that is designed to support all of Oklahoma`s oil industry, with particular emphasis on smaller companies and independent operators in their attempts to maximize the economic producibility of FDD reservoirs. Specifically, this project will identify all FDD oil reservoirs in the State; group those reservoirs into plays that have similar depositional and subsequent geologic histories; collect, organize and analyze all available data; conduct characterization and simulation studies on selected reservoirs in each play; and implement a technology transfer program targeted to the operators of FDD reservoirs to sustain the life expectancy of existing wells with the ultimate objective of increasing oil recovery. The elements of the technology …

Timely and repeatable alignment of the 192 beam National Ignition Facility (NIF) laser will require an automatic system. Demanding accuracy requirements must be met with high reliability at low cost while minimizing the turnaround time between shots. We describe an approach for internally self-consistent alignment of the mirrors in the laser chains using a network of local light sources that serve as near field and far field alignment references. It incorporates a minimum number of alignment lasers, handles many beams in parallel, and utilizes simple control algorithms.

Interest has developed in using algae to fix CO{sub 2} to produce oxygen and biomass for life-support in space, and for reducing CO{sub 2} emissions from power plants. A novel photobioreactor (PBR) system using light-emitting diodes (LEDs) as a sole light source was constructed and operated with continuous medium perfusion. Direct internal illumination by 680 nm LEDs could deliver as high as 50 mW/cm{sup 2} of light into the culture medium. Gas transfer by internal sparging had the capacity to transfer 250 mmol O{sub 2}/L culture/h. Nutritional limitations could be overcome by continuous perfusion, supplying the medium components to the culture without increasing osmolarity, while removing potentially inhibitory cellular wastes. When the PBR operated in a continuous perfusion mode with a perfusion rate of 6 reactor volumes a day (6 VVD), it could support ultra high-density algal cultures up to cell concentrations of 4 {times} 10{sup 9} cells/mL and total cell volume fractions of 9.4% v/v (about 25 g dry weight/L). The oxygen production rate at its peak was 13 to 15 mmol/L culture/h. This performance represents the highest reported cell densities attained in photoautotrophic cultures. Continuous perfusion allowed for long-term stable oxygen production, while oxygen production in batch mode …