High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography (open access)

High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography

Shock waves passing through a metal sample can produce ejecta particulates at a metal-vacuum interface. Holography records particle size distributions by using a high-power, short-pulse laser to freeze particle motion. The sizes of the ejecta particles are recorded using an in-line Fraunhofer holography technique. Because the holographic plate would be destroyed in an energetic environment, a high-resolution lens has been designed to relay the interference fringes to a safe environment. Particle sizes within a 12-mm-diameter, 5-mm-thick volume are recorded onto holographic film. To achieve resolution down to 0.5 μm, ultraviolet laser (UV) light is needed. The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution and operates at f/0.89 will be described. To set up this lens system, a doublet lens is temporarily attached that enables operation with 532-nm laser light and 1100 lp/mm resolution. Thus, the setup and alignment are performed with green light, but the dynamic recording is done with UV light. During setup, the 532-nm beam provides enough focus shift to accommodate the placement of a resolution target outside the ejecta volume; this resolution target does not interfere with the calibrated wires and pegs surrounding the ejecta volume. A television microscope archives images of …
Date: August 29, 2008
Creator: Malone, Robert M.; Capelle, Gene A.; Frogget, Brent C.; Grover, Mike; Kaufman, Morris I.; Pazuchanics, Peter et al.
System: The UNT Digital Library
Advances in academic video game collections (open access)

Advances in academic video game collections

This article discusses how the UNT Media Library developed a video game collection to support student retention, student recreation, and classroom instruction. The article also will explain how the Library successfully met challenges involved in collection development, related technology, space needs, and the challenges it sees ahead.
Date: August 29, 2020
Creator: Robson, Diane; Sassen, Catherine & Rodriguez, Allyson
System: The UNT Digital Library
Technology Issues and Benefits of a Fast Ignition Power Plant with Cone Targets (open access)

Technology Issues and Benefits of a Fast Ignition Power Plant with Cone Targets

The use of cone focus, fast ignition targets, either for direct or indirect drive, promises to lower the required driver size and relax the symmetry requirements in IFE power plants. It may also allow use of chamber concepts previously thought infeasible with a laser driver. These benefits will lower the COE and make IFE plants more competitive at smaller size. Their use also raises unique issues that will impact the design and development of power plant subsystems. Cone targets have a significant mass of high Z material whether or not they have a hohlraum and they are not spherically symmetric. This has implications for target injection, tracking and chamber background gas allowable.
Date: August 29, 2003
Creator: Hogan, W. J. & Meier, W. R.
System: The UNT Digital Library