Cygnus is a high-energy radiographic x-ray source. Three large zoom lenses have been assembled to collect images from
large scintillators. A large elliptical pellicle (394 × 280 mm) deflects the scintillator light out of the x-ray path into an
eleven-element zoom lens coupled to a CCD camera. The zoom lens and CCD must be as close as possible to the
scintillator to maximize light collection. A telecentric lens design minimizes image blur from a volume source. To
maximize the resolution of objects of different sizes, the scintillator and zoom lens are translated along the x-ray axis,
and the zoom lens magnification changes. Zoom magnification is also changed when different-sized recording cameras
are used (50 or 62 mm square format). The LYSO scintillator measures 200 × 200 mm and is 5 mm thick. The
scintillator produces blue light peaking at 435 nm, so special lens materials are required. By swapping out one doublet
and allowing all other lenses to be repositioned, the zoom lens can also use a CsI(Tl) scintillator that produces green
light centered at 540 nm (for future operations). All lenses have an anti-reflective coating for both wavelength bands.
Two sets of doublets, the stop, the scintillator, and the CCD camera move during zoom operations. One doublet has x-y
compensation. Alignment of the optical elements was accomplished using counter propagating laser beams and
monitoring the retro-reflections and steering collections of laser spots. Each zoom lens uses 60 lb of glass inside the 425
lb mechanical structure, and can be used in either vertical or horizontal orientation.
The National Ignition Facility (NIF) has a need for measuring gamma radiation as part of a nuclear diagnostic program.
A new gamma-detection diagnostic uses 90° off-axis parabolic mirrors to relay Cherenkov light from a volume of
pressurized gas. This nonimaging optical system has the high-speed detector placed at a stop position with the
Cherenkov light delayed until after the prompt gammas have passed through the detector. Because of the wavelength
range (250 to 700 nm), the optical element surface finish was a key design constraint. A cluster of four channels (each
set to a different gas pressure) will collect the time histories for different energy ranges of gammas.
The National Ignition Facility will begin testing DT fuel capsules yielding greater than 1013 neutrons during 2010.
Neutron imaging is an important diagnostic for understanding capsule behavior. Neutrons are imaged at a scintillator
after passing through a pinhole. The pixelated, 160-mm square scintillator is made up of 1/4 mm diameter rods 50 mm
long. Shielding and distance (28 m) are used to preserve the recording diagnostic hardware. Neutron imaging is light
starved. We designed a large nine-element collecting lens to relay as much scintillator light as reasonable onto a 75 mm
gated microchannel plate (MCP) intensifier. The image from the intensifier's phosphor passes through a fiber taper onto
a CCD camera for digital storage. Alignment of the pinhole and tilting of the scintillator is performed before the relay
lens and MCP can be aligned. Careful tilting of the scintillator is done so that each neutron only passes through one rod
(no crosstalk allowed). The 3.2 ns decay time scintillator emits light in the deep blue, requiring special glass materials.
The glass within the lens housing weighs 26 lbs, with the largest element being 7.7 inches in diameter. The distance
between the scintillator and the MCP is only 27 inches. The scintillator emits light with 0.56 NA and the lens collects
light at 0.15 NA. Thus, the MCP collects only 7% of the available light. Baffling the stray light is a major concern in the
design of the optics. Glass cost considerations, tolerancing, and alignment of this lens system will be discussed.
The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution at a 355-nm wavelength
(ultraviolet) has been completed. By adding a doublet to this lens system, operation at a 532-nm wavelength (green) with
>1100 lp/mm resolution is achieved. This lens is used with high-power laser light to record holograms of fast-moving
ejecta particles from a shocked metal surface located inside a test package. Part of the lens and the entire test package are
under vacuum with a 1-cm air gap separation. Holograms have been recorded with both doubled and tripled Nd:YAG
laser light. The UV operation is very sensitive to the package window's tilt. If this window is tilted by more than 0.1
degrees, the green operation performs with better resolution than that of the UV operation. The setup and alignment are
performed with green light, but the dynamic recording can be done with either UV light or green light. A resolution plate
can be temporarily placed inside the test package so that a television microscope located beyond the hologram position
can archive 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 are presented. Resolution variation across
the 12-mm field of view and throughout the 5-mm depth of field is discussed for both wavelengths.
High-speed microchannel plate (MCP)-based imagers are critical detectors for x-ray diagnostics employed on
Z-experiments at Sandia National Laboratories (SNL) to measure time-resolved x-ray spectra and to image dynamic
hohlraums. A multiframe design using eight half strips in one imager permits recordings of radiation events in discrete
temporal snapshots to yield a time-evolved movie. We present data using various facilities to characterize the
performance of this design. These characterization studies include DC and pulsed-voltage biased measurements in both
saturated and linear operational regimes using an intense, short-pulsed UV laser. Electrical probe measurements taken to
characterize the shape of the HV pulse propagating across the strips help to corroborate the spatial gain dependence
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 scattered and unscattered
light to a safe environment where the interference fringes are recorded on film. These interference fringes allow particles
to be reconstructed within a 12-mm-diameter, 5-mm-thick volume. To achieve resolution down to 0.5 μm, both a high-resolution
optical relay lens and ultraviolet laser (UV) light were implemented. 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.