Engineering the Petawatt Laser into Nova (open access)

Engineering the Petawatt Laser into Nova

The engineering process of integrating the Petawatt (10{sup 15} watts) laser system into the existing 30 kJ (UV) Nova laser at Lawrence Livermore National Laboratory (LLNL) is described in detail. The nanosecond-long, chirped Petawatt laser pulse is initially generated in a separate master oscillator room and then injected into one of Nova`s 10 beamlines. There, the pulse is further amplified and enlarged to {approximately}{phi}60 cm, temporally compressed under vacuum to <500 fs using large diameter diffraction gratings, and then finally focused onto targets using a parabolic mirror. The major Petawatt components are physically large which created many significant engineering challenges in design, installation and implementation. These include the diffraction gratings and mirrors, vacuum compressor chamber, target chamber, and parabolic focusing mirror. Other Petawatt system components were also technically challenging and include: an injection beamline, transport spatial filters, laser diagnostics, alignment components, motor controls, interlocks, timing and synchronization systems, support structures, and vacuum systems. The entire Petawatt laser system was designed, fabricated, installed, and activated while the Nova laser continued its normal two-shift operation. This process required careful engineering and detailed planning to prevent experimental downtime and to complete the project on schedule.
Date: December 23, 1997
Creator: Tietbohl, Gregory L.; Bell, Perry M.; Hamilton, Ronald M.; Horner, Jeffrey B.; Horton, Robert L.; Ludwigsen, Arthur P. et al.
System: The UNT Digital Library
Using the cosmic microwave background to discriminate among inflation models (open access)

Using the cosmic microwave background to discriminate among inflation models

The upcoming satellite missions MAP and Planck will measure the spectrum of fluctuations in the Cosmic Microwave Background with unprecedented accuracy. I discuss the prospect of using these observations to distinguish among proposed models of inflationary cosmology.
Date: December 23, 1997
Creator: Kinney, W. H.
System: The UNT Digital Library
Optical assembly and alignment for the National Ignition Facility project (open access)

Optical assembly and alignment for the National Ignition Facility project

The National Ignition Facility (NIF) will use about 8,000 large optics to carry a high-power laser through a stadium-size building, and will do so on a very tight schedule and budget. The collocated Optics Assembly Building (OAB) will assemble and align, in a clean-room environment, the NIF`s large optics, which are the biggest optics ever assembled in such an environment. In addition, the OAB must allow for just-in-time processing and clean transfer to the areas where the optics will be used. By using a mixture of off-the-shelf and newly designed equipment and by working with industry, we have developed innovative handling systems to perform the clean assembly and precise alignment required for the full variety of optics, as well as for postassembly inspection. We have also developed a set of loading mechanisms that safely get the clean optics to their places in the main NIF building.
Date: December 23, 1997
Creator: Hurst, P. A.; Grasz, E. L.; Wong, H.; Schmitt, E. H. & Simmons, M. R.
System: The UNT Digital Library
Recent advances and challenges for diode-pumped solid-state lasers as an inertial fusion energy driver candidate (open access)

Recent advances and challenges for diode-pumped solid-state lasers as an inertial fusion energy driver candidate

We discuss how solid-state laser technology can serve in the interests of fusion energy beyond the goals of the National Ignition Facility (NIF), which is now being constructed to ignite a deuterium-tritium target to fusion conditions in the laboratory for the first time. We think that advanced solid-state laser technology can offer the repetition-rate and efficiency needed to drive a fusion power plant, in contrast to the single-shot character of NIF. As discuss below, we propose that a gas-cooled, diode-pumped Yb:S-FAP laser can provide a new paradigm for fusion laser technology leading into the next century.
Date: December 23, 1997
Creator: Payne, S.A.; Beach, R.J. & Bibeau, C.
System: The UNT Digital Library
Study of the effects of polishing, etching, cleaving, and water leaching on the UV laser damage of fused silica (open access)

Study of the effects of polishing, etching, cleaving, and water leaching on the UV laser damage of fused silica

A damage morphology study was performed with a 355 nm Nd:YAG laser on synthetic UV-grade fused silica to determine the effects of post- polish chemical etching on laser-induced damage, compare damage morphologies of cleaved and polished surfaces, and understand the effects of the hydrolyzed surface layer and waste-crack interactions. The samples were polished , then chemically etched in buffered HF solution to remove 45,90,135, and 180 nm of surface material. Another set of samples was cleaved and soaked in boiling distilled water for 1 second and 1 hour. All the samples were irradiated at damaging fluencies and characterized by Normarski optical microscopy and scanning electron microscopy. Damage was initiated as micro-pits on both input and output surfaces of the polished fused silica sample. At higher fluencies, the micro-pits generated cracks on the surface. Laser damage of the polished surface showed significant trace contamination levels within a 50 nm surface layer. Micro-pit formation also appeared after irradiating cleaved fused silica surfaces at damaging fluences. Linear damage tracks corresponding cleaving tracks were often observed on cleaved surfaces. Soaking cleaved samples in water produced wide laser damage tracks.
Date: December 23, 1997
Creator: Yoshiyama, J.; Genin, F.Y.; Salleo, A.; Thomas, I.; Kozlowski, M.R.; Sheehan, L.M. et al.
System: The UNT Digital Library
Transport and handling of National Ignition Facility beamline optic modules (open access)

Transport and handling of National Ignition Facility beamline optic modules

Installing the thousands of optics that make up the laser for the National Ignition Facility (NIF) is a complex operation. This paper introduces the Optical Transport and Material Handling designs that will be used to deliver the optics. The transport and handling hardware is being designed to allow autonomous, semiautonomous, and manual operations.
Date: December 23, 1997
Creator: Yakuma, S. C.; Grasz, E. L.; Rowe, A. W.; Yourchenko, G.; Swan, D. A. & Robles, G. M.
System: The UNT Digital Library