A Fisheye Lens for Many-Point PDV

Author Institution: National Security Technologies, LLCSlides presented at the 6th Annual Photonic Doppler Velocimetry (PDV) Workshop held at Lawrence Livermore National Laboratory, Livermore, California, November 3-4, 2011

Historical Perspective on the Evolutionof MPDV Probe Designs

Author Institution: National Security Technologies, LLCSlides presented at the 2016 Photonic Doppler Velocimetry (PDV) unclassified program, Bankhead Theater, Livermore, California, June 7 - 9, 2016. Afternoon program, June 8, 2016

PDV Probe Design with Stereo Imaging

Author Institution: National Security Technologies, LLCSlides presented at the 7th Annual Photonic Doppler Velocimetry (PDV) Workshop held at Sandia National Laboratory, Albuquerque, New Mexico, October 22-23, 2012

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 resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens will be presented, and resolution variation through the 5-mm depth of field will be discussed

Design, construction, alignment, and calibration of a compact velocimetry experiment

A velocimetry experiment has been designed to measure shock properties for small, cylindrical, metal targets (8 mm diameter × 2 mm thick). A target is accelerated by high explosives, caught, then retrieved for later inspection. The target is expected to move at a velocity of 0.1 to 3 km/sec. The complete experiment canister is ~105 mm in diameter and 380 mm long. Optical velocimetry diagnostics include the Velocity Interferometer System for Any Reflector (VISAR) and photon Doppler velocimetry (PDV). The packaging of the velocity diagnostics is not allowed to interfere with the foam catchment or an X-ray imaging diagnostic. Using commercial lenses, a single optical relay collects Doppler-shifted light for both VISAR and PDV. The use of fiber optics allows measurement of point velocities on the target surface for accelerations lasting for 3 mm of travel. Operating at 532 nm, the VISAR has separate illumination fibers requiring alignment. The PDV diagnostic operates at 1550 nm but is aligned and calibrated at 670 nm. VISAR and PDV diagnostics are complimentary measurements that image spots in close proximity on the target surface. Because the optical relay uses commercial glass, optical fibers’ axial positions are offset to compensate for chromatic aberrations. The optomechanical design requires careful attention to fiber management, mechanical assembly and disassembly, foam catchment design, and X-ray diagnostic field of view.Calibration and alignment data are archived at each assembly sequence stage. The photon budgets for the VISAR and PDV diagnostics are separately estimated

Triature Doppler Velocimeter

Author Institution: Los Alamos National LaboratoryAuthor Institution: National Security Technologies, LLCSlides presented at the 3nd Annual Photonic Doppler Velocimetry (PDV) Conference and Workshop held at Sandia National Laboratories, Albuquerque, New Mexico, September 3-4, 2008