A real time technique to measure phonon dynamics using the Raman induced phase conjugation technique in combination with streak-camera technology is described. The technique is used to carry out spectral measurements of the third order nonlinear susceptibility and to determine vibrational and optical phonon dephasing kinetics in liquids and solids

Time-resolved spectroscopy of condensed phase rearrangements is discussed and illustrative examples are presented. A femtosecond pulse initiates phase-coherent nuclear motion in nearly any medium through which it passes, through either optical absorption or impulsive stimulated light scattering. Acoustic phonons, optic phonons, molecular vibrations, or other types of motion may be driven. Once initiated, these motions can be monitored in real time with additional short pulses. In some cases the motion underway may lead to chemical or structural rearrangement of the sample. Examples of structural phase transitions, chemical reactions, and molecular dynamics in the liquid state are discussed.

The molecular dynamics of liquids in the frequency range 100 GHz to tens of THz are conveniently interrogated with broadband femtosecond laser pulses through the time resolved optical Kerr effect. .The molecular dynamics are extracted from the data by a combination of the traditional semi-log plot analysis for diffusive relaxations, and a novel Fourier transform analysis for the intra- and inter molecular vibrational dynamics. These techniques are applied to the optical Kerr dynamics of liquid iodobenzene at room temperature, providing evidence for the presence of both librational motion (at short times) and diffusive reorientation (at longer times) about two distinct molecular axes.

In this paper a non-synchronous scanning streak camera has been used for measuring time-resolved spectra of low-light-level fluorescence. Princeple and method of the measurement are described in detail. The measuring results for typical samples are given with time resolution of 10 ps. The time range of the measurement is from subnanosecond to 10 ns. The spectral band is in visible region. The effects of the streak camera and other parts of the system on the measuring results are analysed.

We have developed a new system for measuring picosecond electrical waveforms, where the advantages of electro-optic sampling are maintained, but the need for a complex short-pulse-laser is eliminated. The system utilizes two advanced technologies; an optical oscilloscope which is a conceptually new optical waveform analyzer with picosecond time resolution, and an electro-optic modulator for electric to optical signal convertor. Using this system, the waveform of the driving current and optical pulses from a laser diode have been simultaneously measured with the temporal resolution of < 25 ps.

The general characteristics of an electronic camera used in the analysis of high speed photonic phenomena and consequently those of an automatic image acquisition and processing system built around these cameras can be divided into two categories : - The first covers the characteristics specific to the image converter tube used, such as the size and spectral response of the photocathode, its spatial and temporal resolutions, dynamic geometric distorsion, cut-off ratio, etc. - The second are those related to the performance of the electronic control circuits : . sweep ramp linearity, . triggering delay and jitter, . sweep times, . transients that occur while the tube's internal voltages are established during aperture control, etc. The major criteria for evaluating a tube with respect to dynamic operation, which by itself is of interest to the user, will be presented during a brief review of theory. The effect on the quality of the image obtained in terms of the duration and number of Nyquist points in the time analysis window, the resulting Bandwith, spatial resolution and cross-talk will also be shown. These criteria can also be used to determine the improvements in the performance of the TSN 506 camera and the NORMA system obtained by using RTC P 510 and ITT F 4157 image converter tubes. We shall conclude with a brief review of tubes currently being developed, their proven and expected characteristics and their impact on the development of electronic cameras and automatic photon measuring systems.

The mechanism of the occurrence of the crosstalk in the streak camera has been experimentally investigated. The results have shown that the main causes are the light scattering from the accelerating electrode in the streak tube, the electron scattering between the MCP output face and the phosphor screen and the light scattering in the output glass window. Basing on the results, the improvement has been tried for above each item and good results are being obtained.

The space charge effects in the magnetic focusing femtosecond streak tube have been analyzed by some experiments and computer simulations. The computer simulations have been very precisely performed, especially with respect to obtaining the transient and three dimensional solution. The results have shown that the accumulation of space charge effects between the photocathode and the deflection electrode induces the broadening of the emitted photoelectron packet along the tube axis and it seriously degrades the temporal resolution at high intensity light level in femtosecond range. The detail mechanism of space charge temporal broadening has been clarified. The improvement method of the broadening is referred, too.

This paper describes a method used by EG&G Energy Measurements, Inc., to obtain high performance in a fast streak camera by using a magnification-equals-zero in the time direction. This method improves the dynamic range and temporal resolution and lowers chromatic aberrations. The results of the measurements on the streak tube and camera are provided herein.

A technique for calibrating the flat-field response and geometric distortion of optical streak cameras using high-power lasers and electro-optic pulse shaping hardware was reported previouslyl. The laser hardware provides a temporally-flat light pulse that can be used to calibrate streak cameras operating with sweep durations of 3-10 ns. Although this technique is successful, the hardware involved is expensive and the process is complex. Based on the analysis of calibrations made at these fast sweep rates, we developed a new technique to measure the flat-field response of an optical streak camera using an array of visible light emitting diodes (LED) and a slow (~10 μs) sweep generator. We will discuss the new slow technique, and will present a comparison between calibration measurements made using the two techniques.

We present here the P850X streak tube which is a high spatio-temporal resolution X-ray converter tube designed for laser interaction X-ray diagnostics. This tube experiments a new design of electron optics allowing separate focusing of the beam along the temporal and spatial axis. It includes a small dimension screen which must be coupled, for use in X-ray diagnostics, to an image intensifier. To take into account the high resolution of the P850X tube this image intensifier has been improved. Moreover reduced dimensions of the screen and of the associated image intensifier are well fitted with a direct electronic (CCD) readout recording. We also describe the new camera built around the tube, which presents a completely new structure, including a digital monitoring of all the high voltages applied to the tube.

We present here the P552 soft X-ray streak tube which is derived from the P500-P550 X-ray tube from RTC 1. To meet the requirements of X-ray diagnostics in high power laser interaction experiments performed at Centre d' Etudes de Limeil-Valenton some modifications were carried out to allow an easier control of the photocathode and the insertion of an optical fiducial of the laser pulse. We describe the main features of the whole device. This tube associated with a Thomson 2 TSN 505 camera has been used in laser plasma experiments and we present here some results obtained on the PHFBUS laser facility at CEL-V.

The influence of a streak tube system on the noise properties of the signal is analyzed. The streak system is modeled as a cascade of stochastic amplifiers and a system transfer function for the signal statistics developed in terms of the Z transform of each stage. The output signal variance is calculated from the model and compared with experimental data.

Several scientific programs at Lawrence Livermore National Laboratory (LLNL) require instrumentation that can capture optical signals with high fidelity. Typically, they require high temporal resolution, high spatial resolution, and high dynamic range. The instrument of choice for most of these multichannel, data-recording applications is the optical streak camera. We have evaluated three optical streak camera systems under similar conditions: (1) the EG&G model L-CA-15 streak camera, designed and built under U.S. Department of Energy (DOE) contract, with a streak tube designed for a time response of a few picoseconds; (2) an in-house (LLNL) design, with an ITT F4157 streak tube that operates in the extraction mode; and (3) a Thomson-CSF model TSN 506 streak camera, with an ITT F4157 streak tube that also operates in the extraction mode. All three systems were found to be capable of time response better than 40 ps FWHM, a dynamic range of greater than 100, and spatial resolution greater than 5 line pairs per millimeter (lp/mm). The experimental setup and plots of results are presented and discussed.

Electronic streak cameras are used to record subnanosecond data at the Nevada Test Site. It has been found that externally induced variations in the photocathode voltage of the streak tube can produce both temporal and spatial errors on the output image. An elec on beam tracing code was used to model the magnification as a function of photocathode voltage and signal input position for streak tubes manufactured by RCA, ITT, and Kentech. Las tests were also performed where pulsed and radio frequency signals were induced upon the photocathode and the errors on e resultant image were compared with e error sredict-s by the electron II - am code. Also, methods for processing the distortion in digitized images were investigated. This pas r will discuss the results of these investigations.

Steady advancement has been made in bringing photonic recorder technologies from a pure research and development stage to the practical laboratory and fielding environment. Streak camera-based systems have been incorporated into large data recording systems and have shown significant improvement in channel density and single-shot bandwidth. In particular, remote photonic sensing using fiber optic cables to transmit the information to the recorder has shown advantages over conventional coax cable methods. One streak camera-based recorder system has been designed into the underground test (UGT) data acquisition system. The design allowed for video rate readout, redundant digitized image storage, UGT system compatibility, and full real time system diagnostics. Another stand-alone streak camera-based recorder has been designed that incorporates an IEEE-488 interface and a unique software package. Operation of this photonic recorder system (PRS-1000), as either a streak imaging recorder or as a high-speed multi-channel data recorder (HSMCDR), has been greatly simplified through use of the icon-driven, window-based custom software. An overview of photonic recording methods will be presented along with the details of the PRS-1000 and the associated system software.

We studied the focusing properties of an ITT F4157 image tube that was biased at voltages far from the original design and is used for operation in an ultrafast (10 ps) streak camera. Its output resolution at streak camera operating potentials was measured as a function of input slit width, incident-light wavelength, and focus-grid voltage, with results similar to those reported for the RCA C73435 streak tube. The temporal resolution is insensitive to focus-grid voltage for a narrow (50 μm) input slit, but is very sensitive to focus-grid voltage for a wide (500 μm) input slit. Spatial resolution is nearly independent of focus-grid voltage for values that give good temporal resolution. Both temporal and spatial resolution depend on the incident-light wavelength. Streak camera operation is simulated with a computer program that calculates photoelectron trajectories. Electron ray tracing describes the observed effects of slit width, incident-light wavelength, and focus-grid voltage on the output resolution.

Building diagnostics for characterizing 1-ps duration ultra-high brightness laser sources and their interaction with solid targets is a very complex task for the streak camera community. Generally, single-shot, 1-ps time resolution, large-dynamic range instrumentation is beyond current capabilities. In this paper, we discuss some of the limitations of present day streak camera technologies. The difficulty of the task is illustrated with some preliminary x-ray streak data from the interaction of a pair of picosecond laser pulses with a Cu target at 2 x 10¹⁵ W/cm².

Users of the ITT F4113 proximity-focused image intensifier tube have generally been unable to obtain its specified resolution when using it to amplify streak tube images. As well as reduced high-frequency resolution, some output light can be detected at distances as great as a few millimeters from the input image. This long-range light spreading is called veiling glare. In this paper we present measurements and propose the cause of the F4113's veiling glare. The most probable cause is electron scattering at the front surface of the microchannel plate, with some contribution due to electron scattering at the phosphor. The cause of reduced resolution at higher spatial frequencies is also discussed. This is most likely due to the combined effects of phosphor thickness, photographic film thickness and the high numerical aperture of the fiber optics. Finally, some improvements have recently been made to the F4113. These are described and possible additional improvements are suggested.

The interaction of pulsed, high-intensity (I>10¹⁴ W/cm2) laser light with a solid target typically produces a dense plasma that radiates significantly in the soft x-ray region of 0.1-10 keV.1 Important information concerning the dynamics of the laser-produced plasmas can be obtained through time-resolved imaging and spectroscopy of the x-ray emission. In particular, high-resolution x-ray imaging provides a direct means of studying the evolution of temperature and density profiles of the plasma, as well as the hydrodynamics which govern its expansion. Since the expansion velocities can be in excess of 107 cm/s, the frame duration of the time-resolved image must be less than 100 ps to avoid significant blurring. In addition, the laser-produced plasmas are usually small and have large density gradients, particularly at early times. Consequently, it is desirable that the imaging system be able to resolve structure on a spatial scale of 1-10 μm. In this paper we describe the development of a high resolution x-ray framing cameral (XFC) to be used to image the soft x-ray emission from laser-produced plasmas on a picosecond timescale. The XFC generates a single frame with 50 ps temporal resolution 22 pm spatial resolution at the image plane and real time readout. The camera is optically triggered, resulting in jitter-free synchronization of the frame time with the laser experiment, making it possible to integrate multiple shots with no loss of temporal resolution. One of the first applications of the XFC will be to image the dynamic implosion of micro-balloon fuel pellets for laser fusion using the Nova 10-beam laser system.

Gated X-ray microchannel plate detectors and images have become very useful and reliable diagnostics on Nova. We have now better characterized these stripline instruments with respect to gain, temporal and spatial resolution. Pulse shapers (2 kV - 100 ps) and improvements in pulse propagation allow us to gate x-ray events at 100 ps. We describe new ideas in diagnostics and new methods of improving temporal resolution (<100 ps).

A four-frame, fast gated microchannel plate x-ray detector has been used on the OMEGA laser system to obtain two-dimensional, time-resolved pinhole camera images (in the 1-2.5 keV region) of imploding laser fusion targets. The camera, which has a frame time less than 150 ps has proven to be a valuable tool, both in recording implosion dynamics and in detecting and identifying implosion non-uniformities.

Using a fast-gated (120 psec-5 nsec) microchannel-plate optical camera (Gated Optical Imager), framing photographs have been taken of the rapidly streaming, laser plasma (~5 x 10⁷ cm/sec) passing through a vacuum or a background gas, with and without a magnetic field. Observations of Large-Larmor-Radius Interchange Instabilities are presented.

The requirement for a sensitive two-dimensional imaging diagnostic with picosecond time resolution, particularly in the study of laser-produced plasmas, has already been discussed [1]. A temporal sequence of framed images would provide useful supplementary information to that provided by time resolved streak images across a spectral region of interest from visible to x-ray. To fulfil this requirement the Picoframe camera system has been developed. Results pertaining to the operation of a camera having S20 photocathode sensitivity are reviewed and the characteristics of an UV/x-ray sensitive version of the Picoframe system are presented.

The construction and the applications of an oil-cooled flash x-ray tube to biomedical radiography are described. Generally, this tube was used for the repetitional flash x-ray generator for producing soft x-rays and consisted of the following major parts: a vacuum vessel made of stainless steel with a diameter of 80mm, a ring cathode made of molybdenum of 0.2mm thickness, a rod-shaped anode tip made of tungsten with a diameter of less than 3.0mm for obtaining the high intensity x-rays, an anode rod made of beryllium-copper alloy utilizing cooling fins, an internal x-ray output made of copper having a cooling mechanism, and an air-cooled heat exchanger. The anode tip was mounted on the anode rod and could easily be changed, and the cathode was attached to the internal output mouth of x-rays. The anode-cathode plane space was adjusted from the outside of the x-ray tube by rotating the x-ray diaphragm. The operating voltage was less than 150kV, and the maximum tube current was more than lOkA. The effective focal spot size primarily varied according to the diameter of anode tip and it ranged from 0.5 to 3.0mm in diameter. This tube was connected to two types of high-voltage pulsers: (a) a high voltage repetitional pulser achieved with a frequency control system of less than 20Hz, and (b) a Cockcroft circuit with a high-frequen-cy DC-AC inverter. Various radiographs were obtained by using this tube in conjunction with these pulsers.

Low cost frame reader made of IBM personal computer for high speed videography has been build up, the target position and time code of the frame could be recognized and the trajectory, vlocity and acceleration could be calculated automatically. The block truncation coding and vector quantization has been used for the purporse of data compression, so that image of each frame could be stored in the computer, or transmitted through the telephone line in real time economically.

A 150W compact xenon arc lamp is described, utilizing a mixed-oxide cathode to achieve 85% lumen maintenance at 2,000 hours and positional/brightness stability 7.6 times better than that of conventional lamps. Aspects of lamp stability are defined, and a method for measuring stability is described.

The application of carbon/carbon technology to high speed/high temperature gas turbine systems requires the acquisition of visual data to measure the materials performance. This visualization system provides real time performance of turbine blades rotating at RPM's higher than 50,000 at temperatures above 3000°F. Surface details 15-20 micrometers in size are readily observable. In addition, the viewing window serves as a sample plate for collecting materials that separate from the turbine blades.

The recent introduction of a two dimensional interactive software package provides a new technique for quantitative analysis. Integrated with its corresponding peripherals, the same software offers either film or video data reduction. Digitized data points measured from the images are stored in the computer. With is data, a variety of information can be displayed, printed or plotted in a graphical form. The resultant graphs could determine such factors as: displacement, force, velocity, momentum, angular acceleration, center of gravity, energy, leng, , angle and time to name a few. Simple, efficient and precise analysis can now be quantified and documented. This paper will describe the detailed capabilities of the software along with a variety of applications where it might be used.

High speed photography requires high levels of illumination for good color quality and good color retention. As the frames/second increase, so does the intensity of light required. The HMI is a medium arc, high-efficiency, cool, high-intensity discharge lamp capable of maintaining a 5600 K color temperature at high levels of illumination, with a dramatically reduced level of emitted infrared radiation. The LM-Ballast is designed to take full advantage of the HMI lamp and enhances its performance. The LM-Ballast is a power source installed between the utility power (AC) or battery pack (DC) and the HMI lamp, replacing the more commonly used magnetic ballast. The LM-Ballast provides modified square waves of regulated current. This eliminates flicker problems associated with HMI lamps when used in conjunction with magnetic ballasts. Further, the lamp is operating at cooler internal temperatures and maintains a uniform 5600 K color temperature. The useful life of the lamp is extended from 500 to approximately 2160 hours. The reduction of color temperature, due to ageing, is reduced from 1 K/hr to .3 K/hr. A combination of the HMI lamp and LM-Ballast provides an ideal lighting system for high speed photography. Shooting film at 10,000 fps was performed where no flicker nor shift of color was observed.

High-speed videography (HSV) at 60 frames-per-second (FPS) has since the earliest systems been an attractive goal. Vast numbers of information gathering and motion analysis problems lend themselves to solution at this rate. Seemingly suitable equipment to implement inexpensive systems has been available off-the-shelf. However, technical problems, complexity and economic factors have pushed development toward higher frame rate systems. The application of new technology recently has combined with a shift of the perceived needs of mass (security and consumer) markets to make available the components for truly inexpensive, high-performance 60 FPS HSV systems. Cameras employing solid-state sensors having electronic shuttering built into the chip architecture are widely available. They provide a simple solution to the temporal resolution problem which formerly required synched/phased mechanical shutters, or synchronized strobe illumination. More recently, the crucial need for standard-format (such as VHS) videocorders capable of field sequential playback in stopped- or in slow-motion has been satisfied. The low cost of effective 60 FPS systems will likely be an incentive for a dramatic increase in the general awareness of the power of HSV as a problem-solving tool. A "trickle-up" effect will be to substantially increase the demand for higher performance systems where their characteristics are appropriate.

The field of high-speed videography (HSV) has continued to mature in recent years, due to the introduction of a mixture of new technology and extensions of existing technology. Recent low frame-rate innovations have the potential to dramatically expand the areas of information gathering and motion analysis at all frame-rates. Progress at the 0 - rate is bringing the battle of film versus video to the field of still photography. The pressure to push intermediate frame rates higher continues, although the maximum achievable frame rate has remained stable for several years. Higher maximum recording rates appear technologically practical, but economic factors impose severe limitations to development. The application of diverse photographic techniques to video-based systems is under-exploited. The basics of HSV apply to other fields, such as machine vision and robotics. Present motion analysis systems continue to function mainly as an instant replay replacement for high-speed movie film cameras. The interrelationship among lighting, shuttering and spatial resolution is examined.

This paper outlines an electro-optics system for measuring impact position and velocity of projectile simultaneously. The system uses a series of 5mw He-Ne laser source and photo-diodes detectors to obtain impact position with an accuracy of +/- lmm standard deviation.

The Instrumentation Technology Branch of the Air Force Armament Laboratory is currently involved in the development of several high speed photographic, videographic, and photonic instrumentation systems to support the testing and analysis of developmental weapons and test items under dynamic conditions. These projects include development of a large format (14 inch by 17 inch) laser illuminated Cranz-Schardin shadowgraph system for materials research, development of a solid state imager based shadowgraph system for aeroballistic studies, experiments with gated imagers for a variety of test applications, and experiments with high speed video imagers and illuminators for airborne and range tracking instrumentation. An additional issue discussed is the development of a timing and annotation standard for video imaging instrumentation systems operating at higher than NTSC standard rates.

Video cameras are often used to record the motion of test objects. Manual quantitative measurement of the objects' location and orientation generally requires time consuming analysis of large numbers of images. This paper presents a video tracker using digital imaging techniques, that can automatically track operator-designated features in a sequence of video images. Either the centroid or the edge of a feature can be tracked. The direction of the edge is selected by the operator during track set up, and can be an any angle. Multiple objects in one image and/or multiple features on one object can be tracked. Tracking rates up to 15 images per second are possible. A human operator starts the tracking by designating the feature to be tracked, monitors the automatic tracking, and assists the tracker if necessary. An adaptive threshold maintains automated tracking through changing lighting and background conditions.

The recent development of photographic illuminators using high-power pulsed semiconductor lasers as light sources has demonstrated their attractiveness for this purpose. The small size of these lasers and their modest power requirements permits very compact multiple-source illuminators and cameras to be assembled. Single-image, multiple-exposure and 20-image Cranz-Schardin cameras using film as the recording medium will be described. An orthogonal stereo single-image camera is also described. Although the average power output power of a semiconductor laser is low, they can be employed in applications requiring high average powers for a short time. In back-lit camera systems, framing rates above 2 MHz can be supported. In such an application, experience has shown that duty factors more than 1000 times higher than the normal rating can be obtained without permanent damage to the laser. The effective emitting area of a semiconductor laser is typically a fraction of a millimeter on a side, but the real source actually consists of a set of chip faces arranged in parallel rows. The emitting area of each chip is much longer than it is wide; the typical width being less than ten microns. Care must be exercised in the design of an optical system to avoid having this structure appear on the image.

It is shown that holographic interferometry has an enormous versatility for gasdynamics applicationsl, 2 especially for the shock tube research. The present paper reports recent results of the holographic interferometric shock tube experiment which was conducted in the Institute of High Speed Mechanics, Tohoku University. The experiment was conducted in 60 mm X 150 mm and 30 mm X 40 mm shock tubes equipped with a pulsed laser holographic interferometry. Two topics were presented here, (1) existence of the dust free region and vortex generation over a circular cylinder in a dusty gas shock tube for shock Mach number of 1.3 and 2.2 in air, and (2) interaction of shock waves with vortices which were generated over a 20 mm circular cylinder and at the leading edge of a splitter plate. These models were placed in the 60 mm X 150 mm shock tube for shock Mach number of 1.5 and 2.5. In the dusty gas shock tube flow, the generation of the the dust free region over the cylinder was clarified. The experimental results of shock propagation over cylinders were also compared with the numerical simulation using the TVD finite difference scheme3 applied to the Navier-Stokes equations. Very good agreement was obtained between the interferogram and the numerical simulation. Unsteady shock boundary-layer interaction processes and the formation of the vortices were clearly observable. Consequently, it is emphasized that only hologarphic interferograms can give a direct validations for the recently developing numerical schemes by comparing them with the experimental isopycnics.

The complementary field method has been applied to interferometric tomographic reconstruction of high speed aerodynamic flows involving a shock. It is based on the reconstruction of the complementary field, which is the difference between the object field to be reconstructed and its estimate. The method is iterative and incorporates a priori information. This study demonstrates advantages of the method in alleviating the difficiencies associated with computational reconstructors and measured data. Substantial reconstruction improvement is obtained, especially near a shock when its position is utilized as a priori information. Under the test conditions, convergence is rapid.

By using the voice recognition techniques to recognize the voice signal of the rocket lunghing can help the high speed camera make decision to go on or trun off the film running automatically. The voice recognition techniques and results are discussed in this paper.

We describe an imaging system that we developed to obtain quantitative multispectral visible images of objects from an airborne platform. The system consists of a Multispectral Image Intensified Camera coupled to a real-time image processing system. The image processing system monitors the camera performance in flight. In this article, we describe the image processing system, the multispectral camera, the calibration procedure and present stellar intensity and spectral measurements.

Commercially available mechanical, video, and electronic high-speed imaging systems are compared as part of an attempt to answer the question, will electronic cameras replace film cameras for high-speed recording? Of special interest is the relationship between spatial resolution and frame rate. Equally important is the compatibility of the imaging systems for recording different types of experiments and tests. The resolution of a number of systems that represent various classes of framing cameras has been compared at their maximum framing rate. Included are several classes of mechanically advanced framing cameras, electronic streak cameras operated in a framing mode, and high-speed video systems. Likewise, the resolution of various classes of streak and image motion cameras has been compared at their maximum temporal resolution. The results: at frame rates up to 25 Mf/s, mechanical cameras can record from 10 to 100 times more data per frame and several times as many frames per run as existing electronic cameras, and from 100 to 1000 times more data per frame than existing video cameras. Video systems are limited in resolution and speed but provide instant access to data. Electronic cameras provide faster frame and streak rates than mechanical cameras (up to 600 Mf/s) but are limited in resolution. Neither of these "electronic" technologies is expected to replace mechanical technologies for frame rates up to a few million frames per second. Future development of new electronic technologies using CCD arrays, however, may result in devices that are more competitive with conventional film techniques.

Recent applications have shown the benefits that can be obtained by using cavity dumped lasers or pulsed laser diodes to provide 10 to 50 nanosecond exposures in rotating mirror cameras. The design of the optical system is complicated by the built-in optical restraints inherent in the design of rotating mirror cameras. These must be dealt with in order to provide satisfactory results. Techniques to provide successful designs for using both Streak and Framing Cameras are addressed in this paper.

The Copper Vapor Laser (CVL) has been with us only a few years, but has demonstrated its potential as a high repetition rate strobe for high speed imaging. It has extended the capabilities of high-speed recording equipment by providing intense light and ultrashort pulses to help image events that might have otherwise been lost.

A new technique of electro-optical framing high-speed holography is presented based on the discussion of current framing techniques. The feasibility of the technique is discussed, the influence of multi-exposures on recording sy-stem is analysed. The visibilities of one frame type, frame separate type and frame overlapping type are derived separately,

The paper describes a new and novel video system which combines real time operation at 378 TV line resolution with the ability to capture, on command, a single high resolution 850 TV line image. The camera system incorporates a high resolution image tube giving shuttering periods as short as 200ns. The resulting photographic quality images may be dumped from the digital frame store to a hard copier or transferred to a PC for image enhancement.

A long pulse radiography system is under construction at the Mission Research Corporation (MRC) facility and consists of an intense X-ray source and camera. The bremsstrahlung pulser is designed to operate at 500 kVp, 1000 A, for 25 psec. A dose rate of 1.84 x 10⁵ Rads/sec is expected at a location 1 meter from the vacuum diode. The generation of X-rays is accomplished through the deposition of <10 kJ of electron beam energy in a tungsten target anode. Ablation of the anode material will require periodic replacement of modular components. The X-ray camera uses a scintillator, a gating image intensifier (MCP), and a rotating mirror assembly to transfer the visible output light to the film plane.

Analysis of spray pattern images has been utilized to characterize fuel sprays in various environments. One of the technical challenges in the analysis is to acquire low noise and consistent quality images of particles for accurate measurement. Especially, difficult is the fuel droplet image formation and acquisition in an engine chamber because of the harsh environment and asynchronous nature between an engine and a recording device. This paper describes a system which forms snapshot images of a fuel spray, captures them using a TV camera and records them on a video disk recorder for automatic analysis. The hardware and control software aspects of the imaging system are discussed in this paper.