The photochron family of streak-cameras has been demonstrated to have subpicosecond resolution (1). While pulses from a mode-locked flashlamp-pumped R6G dye laser were adequate for testing the first generation of these cameras, more indirect methods of generating subpicosecond pulses by Raman scattering processes were involved in the evaluation of the performance of the Photochron II system (2). More recently a passively mode-locked CW R6G dye laser has been developed to produce pulses having durations as short as 0.3 psec (3). These pulses have been used to directly measure the camera instrumental function. The streak camera had an S20 photocathode and was tested with ultrashort pulses at 610 nm. For this system the overall camera resolution would be expected to be iA)0.9 psec. We wish to present results which demonstrate directly that this camera has subpicosecond resolution at %600 nm. The performance of an optical multi-channel analyser to record picosecond streak images from this type of camera will also be discussed.

A 5 ps resolution streak camera associated with an analogic video storage system has been developed: the display of the trace on the TV monitor allows the experimenter to evaluate immediately after each laser shot the temporal characteristics of a single mode-locked pulse delivered by a Nd:YAG laser or by a Nd: glass bandwidth limited tunable laser. The memorization of the video signal by means of a storage tube permits an accurate analysis of the light pulse width ; the display includes temporal and intensity calibration signals. In order to reduce the temporal fluctuations of the triggering system of the streak camera, it has been developed (1) an avalanche transistor sweep generator, the sweep voltage presents a linearity better than 10 To over 4 cm of the phosphor screen and a rate of 180 ps/cm ; (ii) a high sensitive tunnel diode trigger, the measurements show that a variation of the laser envelope amplitude of a factor 5 leads to a time jitter of less than 30 ps. Furthermore, using the aforementioned circuit in conjunction with a Pockets cell (CID'A crystal), it is shown that for the previous envelope fluctuations the single output pulse has an amplitude variation of less than 20 %.

We have compared the operating characteristics of five types of image-converter used in picosecond-resolution streak cameras. Operational characteristics of the RCA** C73435 tube, used successfully in the Lawrence Livermore Laboratory (LLL)-designed streak camera and by others, are reviewed, and new dynamic range data are presented. A version of the Instrument Technology, Ltd, (ITL), standard STM100 tube, reduced in size to fit the LLL camera configuration, was operated in our camera and its characteristics were studied. A developmental, magnetically-focused tube, designed in collaboration with International Telephone and Telegraph Corp. (ITT), has also been operated in our streak camera and these data are included. IJeasurements are included on the Hamamatsu 1495X operated in a camera made b the tube manufacturer. Finally, an English Electric Valve, P855, was tested as mounted in a commercial streak camera. Deflection factors, dynamic range, operating voltage requirements and other technical operation characteristics are compared.

The main approacues in designing of PIE-= type multistage image-converter tubes (TOT) aimed to considerably improve their temporal and spatial resolution in the linear streak mode, are outlined on the basis of carried out experiments and theoretical estimations. Shown are the basic models of the high-speed image tubes developed for application in laser and laser plasma researches. Further progress is made in the mode-beats technique utilization for the ICT dynamic parameters definition. The specific features of the double -frequency neodymium-glass lasers are discussed. Some results are presented of the ICT "temporal" modulation transfer function measurements. Uew trends in high-speed ICT development are also suggested.

The variation of dynamic range of a picosecond image converter camera is analysed in terms of its time resolution. It is observed that the dynamic range is proportional to the square of the resolved time. This phenomenon is explained in terms of a photo-electron emission "life-time" which is proportional to the intensity of the photon beam absorbed by the photocathode of the time resolving image converter tube. The implications of this mechanism on the interpretation of picosecond camera results are discussed.

High speed photography of moire fringes was used to analyze the motion of surfaces subjected to dynamic loadings. The moire fringe device used a high power light source, a pair of Ronchi rulings, and commonly available lenses. One Ronchi ruling was projected at an angle onto the surface to be studied. The projected ruling was then imaged onto the second Ronchi ruling where a fringe pattern was produced which was characteristic of the stationary wall before impact. Any outward displacement of the surface caused a corresponding change in the original fringe pattern. Calculations of wall motion from fringe patterns were greatly simplified by the observation that each fringe can be represented as an ellipse which intersects the target (usually in two places) and both the projection and taking lenses.

The purpose of the investigation is measurement of a diffusing surface, normal to a certain reference plane, changing rapidly with time. In this paper are, in the first place, described basic study, based on geometrical optics, of Moire topography using an incoherent or a coherent light source in two procesess. The contents are below; (1) generating the best quality of equispacing fringes on the surface, (2) formation of Moire contour lines and height difference between the most adjacent lines. Next is shown a time resolved Moire topography consisting of casting fringe system using Xe-flash as a light source and a high speed framing camera et al, with a ten microseconds of time resolution and about 150 microns of contour sensitivity. As a typical application when a thin plate was received an impact force, the deformations of the surface are shown in a series of contour lines pictures.

A method of interference measurements using the interferogram in monochromatic light only, while the rest of information is obtained not from the interferogram in white light but by special calculation is proposed. The method has been widely tested in practice and its effectiveness has been verified. It has been successfully used in investigations of supersonic gas flows (axisymmetrical and three-dimensional cases) carried out with the Mach-Zehnder interferometer, with the wavefront shearing interferometer and with holographic methods.

The authors have employed an electro-optical technique to introduce color into achromatic images resulting from any of the refractive recording methods. An achromatic television camera is used as the image detector. Its output is monitored by multiple signal level detectors which switch in preselected color inputs. The addition of achromatic camera signal, switched color signal, and color synchronization information provides a color kinescope image whose spatial characteristics have been determined by the camera input. This paper describes the operation of this system, our qualitative evaluations, and areas for further investigation.

Two "marking apertures" of a schlieren system providing range measurements up to ten millimeters are described. To visualizate strong inhomogeneities in large areas the contrasting screen is proposed which allows color images be obtained as well.

There are several reasons for considering a photoelectronic streak-camera tube utilizing a magnetic electron lens. The high limiting spatial resolution of the magnetic lens offers the potential of achieving high technical time resolution. Also, the magnetic lens allows the use of large active diameter planar and mutually parallel photocathode, acceleration mesh and electron target components. The principal design characteristics of a one-loop-focus magnetic streak-tube having electric field deflection plates are described. Operation in uniform and non-uniform magnetic focus fields is discussed. It is shown that maximum deflection sensitivity is achieved for deflection plates situated at the electron beam focus antinode, and that the output trace is then normal to the deflection electric field.

The paper proposes to estimate temporal resolution of electron-optical jphotochronographic devices by the contrast-temporal method. The Qontrast-temporal characteristics of an image-converter tube were calculated theoretically. It takes into account the influence of cathode-emission time, time difference of , cathode-anode electron transit and relation of beam size on a screen to scanning velocity.

A high speed optical deflection system has been designed for picosecond laser pulse diagnostics. Evaluation of a prototype system indicates that an ultracompact streak camera with picosecond resolution can be constructed from readily available components with a relatively low cost. A commercially available electro-optic beam deflector with a 2-mm aperture ADP crystal is used in the prototype. This unit is capable of deflecting wavelengths from the visible to 1.06 pm. When high power single picosecond pulses are used, previous limitations of electro-optic deflectors due to signal beam absorption, internal heating, and mechanical shock waves are overcome. At 532 nm, a resolution of 18 spot diameters is obtained, while the dynamic range in excess of 200 is limited by the readout system. Use of a crystal material with a much higher electro-optic coefficient produces a theoretical resolution c,omparable to that of electro-optic cameras. The high current required to drive the crystal presents some difficult electronics problems and available solutions are discussed. Readout is accomplished with film, a TV camera, or a linear diode array. Computer manipulation of the output data can be used to improve resolution and dynamic range.

The relative importance of space charge inside an electrostatically focussed tube (i) near the photo-surface and (ii) at the electron trajectory cross-over point is evaluated by comparing the performance of four electrostatically focussed single stage image con-verter tubes. A 3 nanosecond long Nitrogen laser pulse was used for these experiments. The electron optics of these tubes were sufficiently varied, so that a proper evaluation of photo-cathode surface resistance could also be carried out. The results suggest that the most important area of space charge contribution for electron image degradation is the region near the photo-cathode. It was also observed that the degradation of spatial resolution, for an image tube with high photo-cathode conductivity and more than 2 KV/cm2 electric field near the Rhoto-cathode, was not significant until the photo-current density reached above 40 ma/cm'. This current density is much greater than that normally available from picosecond streak tubes, if good time resolution is expected from these tubes. In the light of these experiments, the importance of vacuum space charge in an image tube for picosecond time resolution is discussed.

Here we relate to the method of recording high-speed phenomena to analyze their interference fringes with the combination of real-time holographic interferometry and,high-speed photography. We show first the generation of interference fringes in real-time holographic interferometry. Then we show recorded consequences of high-speed phenomena with the combination of real-time holographic interferometry and rotating prism high-speed camera, streak camera or image converter camera.

In recording high-speed processes by means of holographic method time resolution is usually determined by the laser pulse duration. Effective resolution can be an order improved if one knows the shape of the laser pulse as is shown in this paper. The contrast of the image reconstructed is determined by the moment it appears in the phenomenon under study (if the latter is within the boundaries of the registering pulse). The threshold contrast of discovery of an object is due to the part of the total laser pulse energy absorbed by the object. To measure the threshold contrast the stationary optical wedge is recorded on the hologram. The threshold contrast and laser pulse shape being defined it is possible to caculate the threshold time interval.

Two methods of high speed holocinematography are described using spatial or patial frequency multiplexing for image separation. The experimental devices operate in the range of10 000 to 20 000 holograms per second with a total number of holographic frames of four to eight. Spatial multiplexing is achieved by a rotating disk with apertures placed directly in front of the holographic plate. Spatial frequency multiplexing is obtained with the aid of a special.acousto-optic beam splitter and deflector unit. Objects investigated by both meth-ods are bubbles moving in acoustically generated cavitation bubble fields as well as bubbles formed after laser-induced breakdown in water.

The object of this paper is to present a new holographic method that permits three-dimensional imaging of hypervelocity particle fields with pulse lasers generating pulses having relatively long pulse durations. Dense and/or deep scenes can be imaged, since the temporal filtering properties of holograms permit discrimination between the region of the scene which is of interest and the unwanted region. The holographic configuration embodies a pulse laser source, a three-mirror reflector, a rotating mirror and a holocamera**. The rotating mirror compensates for the scene motion during exposure and the holocamera generates a local reference beam by either amplitude/ wavefront division or spatial frequency component separation method . The role of the three-mirror reflector is to provide an illuminating beam having a time invariant direction in the image space of the rotating mirror. It is shown that this method permits recovery of the three-dimensional velocity vector of each particle, even though the magnitude of the average velocity vector of the particles is much larger than that of the individual relative velocity vector of each particle with respect to another one. Substantial gain in accuracy is gained by using holocameras recording dark-field images. A theoretical study of the method and some results obtained by laboratory simulation are presented.

A holocamera was designed to resolve minute, high-velocity particles. The holocamera was used in conjunction with a light gas gun to investigate the phenomena resulting from the impact of a hypersonic ballistic model with a stationary water droplet. The holocamera used a Q-switched ruby laser light source having an output of 0.25 Joules at 694.3 nm wavelength. The pulse was chopped by means of a pockels cell and a glans polarizer to provide a pulse of 3-5 ns (FWHM). This pulse was split to yield two colinear twin pulses sepa-rated by a time delay. The twin pulses were used to double expose a film plate thereby holographically recording the high-speed phenomena of graphite ejecta issuing from the site of the droplet impact on the ballistic model nosetip. Two holographic techniques were employed. The first displayed the graphite ejecta as dark images silhouetted against a light background. The second technique utilized light forward-scattered around the ejecta to display them as light images against a dark background. For selected impact events both techniques were simultaneously employed. Graphite ejecta were resolved with diameters of 10 pm traveling at velocities of approximately 6.10 km/sec relative to the holocamera.

Classification of methods of recording a set of holograms has been proposed. Classification is based on the principle of coding of three main holographic scheme parameters: reference and object beams and registrator. A new method of high-speed cineholography allowing as well to obtain cross interferograms of the comparison of any two recorded process phases has been proposed. The experimental results are given.

A wide variety of sources yield short pulses of x-rays. Some of these, especially electron-impact devices, have long been used as FXR sources but advances in their performance have been made recently. Other classes of sources, notably high temperature plasmas and synchrotron radiation devices, have become available only in the last few years. The operational and physical characteristics of FXR devices are compared. Flash x-ray machines have powers which range from around 108 W to over 1013 W. The characteristics of x-ray emission generated by such devices are also reviewed. X-ray pulse lengths as short as 10 psec and x-ray powers in excess of 1010 W have been realized. X-ray lasers could yield pulses shorter than 100 fsec with powers greater than 1012 watts. Applications of present flash x-ray sources include stop-motion photography of fast events and rapid production of radiation effects in materials.

A requirement for high-speed cine-radiographic examination of the flight of metallic foreign objects in gas turbines has led to the development of a cine-radiographic systerri suitable for use with constant-potential x-ray sources. The new system has four elements:- ( 1 ) A continuous x-ray source. ( 2 ) A high-gainx-ray image intensifier tube. ( 3 ) A rotating-prism high-speed camera. ( 4 ) A pulse generator. Synchronising impulses are generated within the high-speed camera and these are used to control the pulse generator, which in turn provides gating pulses to the intensifier tube, so that it is switched in step with the. framing action of the camera. The system has so far been used at speeds up to 10,000 frames. s-1 with exposure times down to 10 us. Records have been obtained showing the progress of objects moving at 120 metres. s-1, and the process of pouring castings has also been studied with the equipment.

A sandwich arrangement of indium and calcium tungstate on both sides of an X-ray film, all inside a standard medical aluminium film cassette, was used in making ,shadowgraphs with fast neutrons. When exposed to a neutron flux, the indium plates will store a latent shadowgraph of an object, placed between the neutron source and the sandwich, through an (n,y)--reaction in the indium. The information conveyed by a fast neutron shadowgraph is partially complementary to that of an X-ray picture because fast neutrons are absorbed about equally by both light and heavy elements whereas X-rays are absorbed preferably by the heavy elements. With a sufficiently strong neutron flash source this technique should be applicable in recording fast events. Owing to the relatively long half-life of the activated indium, any other radiation accompanying the neutrons can be eliminated simply by inserting the X-ray film into the cassette only after the exposure of the indium sandwich. The optical density curve of this arrangement was recorded with a continuous source of 2.5-MeV neutrons. It shows that about 1012 neutrons/m2 should produce a useable image. However, this is a quite severe requirement for a flash source of fast neutrons.

The perforation mechanism of metal rods through different thick steel plates has been investigated with multi-channel flash radiography at velocities of up to 3.5 km/s. All rods were circular in cross-section with a length to diameter ratio of 10; the masses varied between 1 and 10 grams; the rod-material was steel. The perforation tests were carried out by means of a two-stage light-gas gun. Three stereo X-ray stations with orthogonal aligned tubes have been used. The first X-ray station gives the orientation of the rod-projectile before perforation. The other two stations observe the orientation and the length- and velocity-reduction after the impact. These X-ray pictures give also information about the deformation of the rod, and the shape of the spray-bubble around the rod. The experiments discussed in this paper were designed to check the validity of the hydrodynamic theory of rod penetration. The velocity-loss of the rods is very low for length-reduction up to 80 %, for higher reductions the residual velocity decreases very rapidly. The results verify the existence of a stationary phase and instationary phases at the beginning and the end of the penetration.

During the collapse of cavitation bubbles in fluids very short and intense shock waves are radiated. Their study is of interest since they contain information about the final collapse phase which is very difficult to record directly. Furthermore, the shock pulses may contribute to the material damage associated with cavitation. Special optical methods taking advantage of the coherence and intensity of laser light have been developed to gain essential data about the shock waves like pulse width and maximum pressure. In one method, classical techniques of observing phase objects like Schlieren or dark-ground are modified in such a way that the accordingly filtered image of the travelling shock wave is scanned by a small pinhole of 5 pm diameter in front of a photomultiplier. In a second method the far-field diffraction pattern produced by the shock wave is recorded photographically. Since this pattern, which is the spatial power spectrum of the shock wave, is independent of the position of the wave, exposure times may be much longer than those required in direct observation of the wave due to its fast propagation. Results of both methods agree rather well and yield pulse widths of the order of lo nsec and pressure amplitudes of some 5o atm referred to 1 mm distance from the center of collapse.

Cavitation problems on marine propellers were studied utilizing several high-speed photographic tools. Cavitation is discussed briefly to permit a better understanding of the photographic subject. Hycam movies at 7500 frames per second were taken to establish the general features of the cavitation process. The bubble collapse phase was then studied using a variable delay trigger and a submicrosecond duration flash. Schlieren methods were used to investigate shock wave generation by bubble collapse.

Gram-size, spherical high-explosive charges were used to produce craters in a variety of cratering media under carefully controlled laboratory conditions. Rotating prism cameras with framing rates up to 7500 pps were used to observe the formation of the crater. and the debris plumes produced by detonation of these charges. Analysis of the high-speed films obtained with these cameras resulted in the measurement of particle displacement, of dynamic strain, and of changes in density of the cratered medium. Quantitative measurements of the velocity and trajectory of particles in the debris plume were obtained with use of a special lighting technique, a still camera, and a rotary shutter.

A pulsed-laser stereophotography system is used to evaluate the physical changes taking place in close (1 pm) proximity to the actinic plasma of miniature exploding foils. The system records stereopairs of photographs at 3 nsec exposures and 20X magnification. The image size is 50 mm square with resolution 40 lines/mm. The purpose of the laser is to supply a short (3 nsec) pulse of monochromatic light. This laser light reflected off the test specimen is then collected by the stereocamera. The 3-nsec pulse minimizes motion blur and the monochromaticity permits filtering out all wavelengths except that of the laser (694.3 nm) wavelength. This permits the self-light of the exploding foils to be, for all practical purposes, eliminated from the stereophotographs. The metal foils provide satisfactory reflection and the plasma acts as an optical absorber and provides for the necessary contrast. The camera includes 1.0-nm narrow band pass filters to prevent recording the exploding foil self-light. The stereopairs are read on a stereo-comparagraph normally used for aerial photographs that has been calibrated for reading these stereophotographs. Since these exploding foils have typical function times of 500 nsec, the stereophotographs are synchronized in time with the event under test. Stereophotographs can be recorded at any preselected time to within ± 20 nsec. This technique provides a means to closely evaluate events near optically intense plasma.

The numerical evaluation of distortions in image converter tubes (ICT) connected with the influence of a high surface resistance of the photocathode was made analytically. The main distortions are additional magnification and barrel distortion. Biplanar ICTs was made for high speed framing cameras which were successfully used in the investigation of exploding wires.

In laser-fusion interactions the effectiveness of coupling laser energy into target compression can be followed by obtaining spatial and temporal information on x-radiation emitted by the target. Microballoon targets now used require temporal resolution of better than a few picoseconds to track accurately target collapse and disassembly. Instabilities of two picoseconds or less are predicted for the process. Most streak cameras are based upon a sector-focused streak tube, which in the design limit is capable of only about 10 ps x-ray resolution. Therefore, a new tube, based upon the proximity-focused or wafer intensifier was developed as a laser-fusion diagnostic capable in the design limit of delivering truly sub-picosecond x-ray resolution. A new power supply was also developed to drive the streak tube. Together, a camera has resulted with true picosecond capability, small size, high sensitivity, broad dynamic range, high spatial resolution, and very low jitter. The system has proved 98% reliable in over 300 laser shots providing data on the collapse of microballoons when irradiated by a dual beam Nd:YAG laser. Theoretical predictions of 2.5 to 3 ps resolution are consistent with experimental data. A visible variant of the design now under construction is expected to give sub-picosecond resolution with advantages similar to the x-ray system.

Improvements in the time resolution of an ultrafast streak-camera for vacuum UV to x-radiation are described. Pin hole optics were used to image the x-rays from a 100 4m laser-produced plasma onto the gold photocathode of the camera. The plasmas were produced by focusing single, amplified (80 mJ) pulses from a mode-locked Nd: glass oscillator on to a copper target. A temporal resolution of <22 psec has been demonstrated in both the oblique and normal incidence modes of operation of the tube. Limits on the ultimate resolution are discussed and a new design for the electron optics of the image tube, which may overcome these limitations, is proposed.

Measurements of the properties of subnanosecond, quenched NE111 plastic scintillators with various concentrations of acetophenone and benzophenone are presented. These quenching agents have been found to very significantly decrease the NE111 decay time. Measurements are made using UV and laser produced x-ray radiations. The scintillations are detected using a visible streak camera with 10 ps resolution. The paper will include measurements of: (1) 10-90% rise time, (2) FWHM, (3) decay time, (4) relative scintillator efficiencies, (5) amplitudes vs. time measurements of the long decay component. All temporal measurements are obtained from a gold cathode ultrafast x-ray streak camera, and the detailed x-ray energy spectrum above 1 keV is also measured using an array of x-ray PIN diodes equipped with the appropriate K-edge filters. Details of the experimental measurements will be discussed and anticipated applications will be included.

A subnanosecond x-ray framing camera technique employing a fiber optics image dissector coupled to a 10 ps optical streak camera will be described. The output data from the streak camera can be reduced from photographic film or directly couple into a SEC Vidicon camera for immediate computer decoding of each scan line into a two dimensional picture. The use of the new subnanosecond plastic scintillator in front of the fiber optics dissector will also be discussed. The paper will include (1) the description of the basic principle, (2) fiber optics's image dissector construction, (3) time resolution considerations, and (4) experimental data on a prototype 7 by 7 array.

In the film The Microchannel Plate the following items are dealt with: the principle of electron multiplication by secondary emission; channel plate manufacture; microchannel plates applications. The applications shown in the film are: Image intensifiers; high-speed photo graphy, X-ray imaging; high-speed oscilloscopy; particle counting and detection of short light events; improvement of sensitivity of a field ion microscope. In this paper these subjects are discussed in the same order as in the film. It provides information additional to the film, with reference to the relevant literature. All illustrations are taken from the actual film copy.

The SYNCHROSPEED camera is specifically designed for synchroballistic use and employs a rotating mirror and fixed film system. The unique feature is that the mirror is triggered into rotation, using a "sky-screen" or other detector, positioned about 50 cms. up-range from the camera position. The mirror reaches its full rotational speed within 450 us. of receiving the trigger pulse, and within this period an electro-mechanical capping shutter is actuated, thus ensuring that the camera is "blind" prior to operation and immediately after the record has been written. The optical system is such that the record is produced on a flat plane, thus permitting the use of Polaroid as well as normal films. The camera writing speed is adjustable between 0.04 and 0. 36mm. /us. , and curves are reproduced which show the characteristics of the mirror and shutter. Pictures are shown of projectiles in flight.

A wide selection of instrumentation is used to provide photographic coverage of hypervelocity test models during flight in the aeroballistic range and track facilities of the von Karin.n Gas Dynamics Facility (VKF). Ultra high-speed framing camera techniques and front-light laser photographic systems are used to study interactions of in-flight test models and their flow fields with various erosive (dust, rain, snow, etc. ) environments. Front-light and back-light photographic systems employing xenon flash lamps as light sources are used for detailed characterization of the erosive fields. Photographic pyrometry systems featuring high-speed image intensifier devices provide measurements of surface temperatures of in-flight test models. Visible-light and x-ray shadowgraphs provide information describing the structural integrity of in-flight models and together with digital timing data comprise very accurate systems for measuring model velocity and aerodynamic coefficients. Finally, highly versatile schlieren systems provide photographic recording of detailed flow field information in black and white or in color. These high-speed photographic techniques are described briefly and several photographic examples are presented.

The pulse ruby laser OGM-20 was used to obtain hypersonic flow patterns. An automatic electronic equipment was developed in order to switch-on the pumping lamps and to open the Pockels shutter at the time moments determined by the actual model velocity. The Interferometer and the Thepler device were employed coupled with the laser light source in hypersonic ballistic experiments. Interferograms and schlieren photos of hypersonic cones are presented. Major advantages or laser lignt sources and limits of its applicability for quantitative optical measurements in hypersonic ballistics are considered.

A technique was developed to measure velocities of thin plastic plates as a continuum with a streak camera at 20 mm/psec and 8.4X magnification. The plastic plates are bonded to an exploding foil with a transparent cylindrical barrel located over the exploding foil/plastic plate laminate on the side of the plastic plate. When the foil is exploded, a plastic plate is torn from the laminate and accelerated through the barrel. The velocity, acceleration, and displacement of 76-μm thick plastic plates moving through a 1 mm diameter barrel 1.5 mm long is recorded on the streak camera. Velocities to 4 mm/psec have been recorded. The actual streak record of the flying plates is recorded when the slit of the streak camera is parallel to the axis of the barrel cylinder. The barrel is backlight-ed with an exploding wire synchronized to function with the event under test. This method provides a shadowgraph record of the flying plate. The streak camera records the advancement of the plate through the barrel which is analogous to the plate velocity. The instantaneous velocity at that particular point is determined by: V = Ws/ (m tan 0) where V = velocity in mm/psec, Ws = writing speed in mm/psec, m = optical magnification, and 0 = angle between the camera slit and the tangent line at the point of interest on the streak record. The most reliable data will be recorded when 0 is near 45°. It is, therefore, desirable to choose Ws and m for a predicted velocity to generate a 0 near 45° and still meet any other requirements of the experiment.

We describe a new method for measuring the shape and position of high-velocity surfaces and shock fronts. Our method involves the use of an optical pin quite similar in appearance to the coaxial, self-shorting, electrical pin commonly used. The ionization of xenon gas in the pin tip produces a light signal that is transmitted by a fiberoptic bundle and recorded using a streak camera. We discuss preliminary data from impact tests indicating a pin signal response of 1 to 2 ns.

The development of fast infrared switches based on reflection from optically induced carries in a semiconductor has proved a new type of shutter for ultrafast photography at mid0infrared waelengths. Preliminary experiments, in which a geranium reflection switch was used in conjunction with pyroelectric vidicon, have permitted nanosecond recording of images formed by 10 μ radiation.

A new type of framing camera tube for either x-ray or optical events is being developed at LLL that should have capabilities of sub-100 psec framing times. The concept of such a camera is based on dissection of an electron-image through a multiple aperture plate in an image converter tube. Each aperture in the plate produces an image frame. By use of synchronized deflection in both the dissector and restorer sections of the tube, the sequentially time-developed images from an aperture are restored to an electron-image frame at the phosphor screen.

A film transport mechanism has been designed so that the image appearing at the fibre optic output window of a microchannel plate intensifier tube is transmitted to film b direct contact, thus ensuring maximum efficiency. Electronic circuits have been developed so that the tube ma) be pulsed for durations from 100 n.s. to 20 n.s with, in addition, a high cut-off ratio where necessary. The camera has been used under various conditions, for surveillance purposes, for photography of moving vehicles in poor light, and for projectile photography, and results are shown. An extension of the technique in the projectile field permits two successive exposures of a single projectile to be obtained.

In "Simple Sequence Photography, D C Emmony combined a 35 mm SLR Camera with a beam-splitting prism to produce this technique. We have since looked at other methods of beam-splitting and possible uses of this system.

A high-speed waiting photochronograph 3CΦK-I with mirror optical system operating in 0.2 μm to 10 μm range is designed. The optical system has two parallel channels forming an image quite similarly. The rotating mirror is polyhedron consisiting of a pair of tetrahedrons fixed on the same axis facing each other at an agle of 45. Such arrangement provides a continuous recording on the light sensitive layer.

In studying gas flow, the physical motion of the medium, is normally made visible by blowing in smoke or lightweight particles. These methods are limited to the observation of more complicated phenomena like turbulence, boundary layer flow or three-dimensional flow. In spark tracing, the luminous ionized plasma channel of an electric spark discharge is the indicator. This offers the particular advantage that it is comparatively mass-free, because the luminous ions of a gas discharge consist of the material of the flowing medium. This method has special advantages with three-dimensional or nonstationary flows, as well as processes of air mixtures in classifiers. The first discharge generates a spark path between two points of wires. If high voltage pulses are now fed to the same electrodes at such high repetition rates that during the interval between two pulses the plasma of the spark has not yet completely deionized, then every subsequent voltage pulse will trace the path of the first spark, which in the meantime has been moved away by the air current.

In this technique UV light is first used to mark an enduring pattern (line, grid, etc.) on a prepared fluid, and the subsequent movement of the pattern and thus the fluid is followed with visible light and high speed photography. The UV light may be pulsed (lasers, flash, mechanically chopped) or continuous, and the visible viewing light may also be pulsed or continuous (lasers, flash, sodium street lamps) depending on the requirements. Time resolution in forming the trace or in observing the trace can be of the order of 10 8 sec. and spacial resolution is in principle optical limits for light of .5μ. The experimental conditions and equipment that have been used will be discussed and compared.

The paper reports on the use of high speed cine photography, at framing rates up to 5000 pps, as a general observational and measurement tool in a large mechanical engineering Group of Companies. In addition, the development of a high speed cinephotographic service will be described and the practical problems associated with the introduction of such a facility into a production situation will be discussed, together with comments on the selection of appropriate equipment. The paper will conclude with a selection of film extracts to illustrate many of the points made in the earlier part of the paper. The general emphasis of the paper is on the practical rather than the theoretical aspects of the application of relatively unsophisticated techniques and apparatus to both the solution of day-to-day production problems and to research and development projects.

Two techniques are used to obtain a direct readout of an ultrafast streak camera. The first method uses a linear solid state Reticon diode array and the second technique entails the use of a SEC vidicon camera. Both methods use fiber optics to couple the light from the output of the streak camera to the sensor. In addition, the SEC vidicon is interfaced to a PDP 11/40 graphics computer system for direct data processing. For both systems, data will be presented as to (1) dynamic range, (2) spatial resolution, (3) linearity, (4) signal processing techniques, and (5) problems and modifications of the devices including mechanical mounting procedure for attaching fiber optics directly to the array chip.

Temporally and spectrally resolved x-ray emission is an important diagnostic tool for the study of target heating and compression induced by sub-nanosecond laser pulses. In this paper we describe the use of the Livermore 15 psec x-ray streak camera to record x-ray emissions in the 1-10 keV range. In particular, we report significant progress during the past year in defining the camera as a quantitative diagnostic instrument, and its implementation for multi-channel, time resolved K-edge filter measurements. Data will be presented which describe x-ray emission from a laser imploded 87 pm diameter glass shell. Channels centered at 2.6, 4.0 and 5.3 keV provide temporal information which we relate to the absorption and compression phases of laser heating. The relative spectral content is found to be in agreement with standard, time integrated measurements.

In this paper we discuss use of the Livermore x-ray streak camera to temporally record x-ray pinhole images of laser compressed targets. Use is made of specially fabricated composite x-ray pinholes which are near diffraction limited for 6 Å x-rays, but easily aligned with a He-Ne laser of 6328 Å wavelength. With a 6 μm x-ray pinhole, the overall system can be aligned to 5 μm accuracy and provides implosion characteristics with space-time resolutions of approximately 6 μm and 15 psec. Acceptable criteria for pinhole alignment, requisite x-ray flux, and filter characteristics are discussed. Implosion characteristics are presented from our present experiments with 68 pm diameter glass microshell targets and 0.45 terawatt, 70 psec Nd laser pulses. Final implosion velocities in excess of 3 x 107 cm/sec are evident.

High speed optical measurements in the picosecond regime play a crucial role in any laser .fusion program. At KMS Fusion,image converter streak cameras have been used to study a high power neodymium glass laser system and to observe target response to the laser pulse. Experimental techniques and results ©I several studies will be discussed. A "pulse stacker" produced the desired pulse shape in 30 psec steps. These stacked trains were monitored at various points along the laser system. Perturbations of the pulse train as it propagates through the laser are most evident at the final output where examples of pulse splitting and breakup, which occur in extreme situations, will be shown. Target diagnostic studies include incident and nonabsorbed laser energy pulse shape and blast-wave photographs to determine absorbed energy.

Described here is the development of various hir7h-spe,,d image-converter cameras(TCC)in-tended for laser and laser plasma diagnostics. The complete set of th designed cameras covred in the linear streak mode the overall recording range of 10^-2- 10^-10 s and 10-12 - 5.10^-9 s in the single-frame mode. The maximum streak temporal resolution is about -1 10 s in the visible and near infrared spectral region. Special attention was paid to 10^-11 the high-speed ICC which provided the maximum streak resolution close to (1-3)•10 A and the minimum sinale-frame exposure of the order of 10^-9 s in the 1-10 Å spectral range. Cameras technical performances as well as their pulsed and supply electronics are brief-ly discussed.T:entioned also are some aspects of the ICC application in laser experirents.

The erosion of metals by sand and dust particles is an industrially important wear pro-cess. In order to study more closely the mechanisms by which impacting particles remove material from a metal surface, experiments were carried out in which hard steel spheres and square plates were fired at metal surfaces. Impact velocities varied from 50 to 350 ms ^-1. Photographs of the impact process taken at a framing rate of 5 x 10⁴ s^-1 with an Imacon image-converter framing camera provided qualitative information on the mechanisms of metal removal. The spherical particles removed metal by a ploughing process, and in certain cases the square plates removed metal by a machining action. Rotation of the square plates during impact was clearly seen in the photographs and had an important effect on the character of the indentation. Quantitative measurements of rebound velocities and rate of spin were made from the photographs; these correlated well with theoretical predictions.

The primary emphasis of this paper is on the application of high speed photography to the study of small-scale, early time events associated with small particle impacts. The term high speed photomicrography has been used to emphasize the fact that magnifications greater than unity are employed in'order to make details of the material response accessible to experimental investigation. The unique combination of this approach and the recently-developed exploding wire particle launch technology, with its inherently high degree of aiming and timing accuracy, offers exciting new possibilities for advancing the state of understanding of the impact process. Photographs obtained on particle impact tests are presented, and their interpretation is discussed. Detailed analysis has been performed for the case of 1 mm diameter glass particles impacting at normal incidence on Plexiglas and fused silica. Various stages of shock wave generation and propagation, damage development and the formation and propagation of various types of fracture are identified. Some other important effects in particle impact are discussed briefly and illustrated by high speed photomicrographs and post-test photomicrographs.

Hardened steel spherical particles 800 and 1000 um in diameter were firedonto blocks of soda lime and borosilicate (Pyrex) glasses at veloqtics up to 300 ms -l. The formation of the damage was photographed at a framing rate of 10's-± with a Beckman and Whitley rotating mirror framing camera to which a microscope was attached. The behaviour of the two glasses was very different; in pyrex glass distinct Hertzian cone cracks were formed, whereas in soda lime such cracks did not appear, but instead finger shaped splinter cracks were formed. Most of the damage occurred within 4-5 us of the impact and it was possible to resolve different modes of cracking during the loading and unloading parts of the impact. Qualitative quasistatic indentation analysis was found to explain the observations in the dynamic case reasonably well.

A vertical water jet leaving a nozzle and penetrating downward into a water body stored in a large container of plexiglas is investigated by using high speed photography. Due to the viscosity and movement of the jet, the front and periphery surfaces of the jet carry ambient air into the water. The air in the water forms bubbles around the jet, which reflect light and made the jet visible in the water. The water jet, impinging on the free water surface and penetrating into the water, causes the change of surface tension on the water surface, which produces the water surface oscillation. The oscillation of the water surface has two effects on the jet flow in the water: (a) Separating the jet front from the jet body. (b) Causing the jet flow to be unstable.

A streak photography technique is described to measure the velocity profile of a microscopic fluid stream forming a fiber in a spin line. Measurements have been made up to filament velocities of 400 meters per minute (image velocity of 8000 mtrs. /min. with 20x magnification), and measurements at greater speeds should be possible. This technique could be used with many existing high speed photography systems and applied to many velocity measuring situations.

One of the more widely used methods for the study of combustion phenomena is the deflexion-mapping method, in combination with Moire techniques. As combustion phenomena are essentially dynamic, multiple frames are generally needed to record the whole event. An exact superposition of each pair of frames may then be done, in order to deduce from the resulting Moire patterns, the change of the thermodynamic variables in the corresponding time interval. We present here a new technique by means of which the superposition of the pairs of frames can be done exactly. This superposition is obtained by comparing a reference speckle pattern registered in each frame with a standard. The reference speckle pattern is provided by an immobile auxiliary diffuser. After developing, a laser beam is directed through the reference region of the nearly superposed pairs of frames, and these are displaced one respect to the other until Young fringes disappear. This yields the criterion of correct superposition. A major advantage of this technique is that the filtering of the Moire patterns corresponding to each pair of frames, and the control of their correct superposition, are made simultaneously on the focal plane of a single lens in a simple optical setup.

A very fast (~ 10 psec) laser light source has been constructed which can be used to make shadowgraph, interferometry, and other diagnostic photographs useful in laser fusion studies. To produce this pulsed light source, a portion of the 100 psec main Nd:glass laser pulse is split off, sent through CS₂ cells to produce a frequency chirp, and then optically compressed by diffraction gratings. By frequency converting the output pulse, one can perform studies at frequencies other than the fundamental (i.e., harmonic or Raman-shifted frequencies). The compressed pulse is absolutely time-synchronized with the main laser pulse. Shadowgrams taken using this technique are shown.

An actively mode-locked Nd:glass ring laser system has been developed to produce a single 200 ps, 1.06 μm pulse synchronized to an intense 1 ns duration CO2 laser pulse. By controlling the build-up of the ring laser pulse and phase locking the modulators of both lasers, synchronization of output pulses to better than 400 ps has been achieved. This arrangement thus permits optical diagnosis of the time development of the CO2 laser produced plasmas. The second harmonic of the Nd:glass laser pulse has been used in inter-ferometric measurements of the electron density and Faraday rotation studies of the spontaneous magnetic field in the CO₂ laser produced plasmas on solid targets. The system will be described together with some preliminary results.

Former studies of high-speed events, e.g. sparkformation and laser produced plasmas by nanosecond light pulses revealed the necessity of shorter exposure times. - This can be done by aid of picosecond light pulses - either a single one or a train of pulses - generated in the cavity of a mode-locked neodymium or a ruby laser. - Schlierenphotos of laser triggered open-air sparks taken by multiple exposure with a series of pulses from a neodymium laser show the advantages of these techniques compared to one dimensional streak photographs. As another example, photos of a plasma induced by a series of ps-light-pulses on a metal surface are shown. - The application of single-pulse techniques is demonstrated by the study of a laser spark, induced by one or two ps pulses in air. In order to get sufficient power for breakdown, the single pulse extracted fro the mode-locked laser passes a two-stage ruby amplifier. - After focalisation, the main part of the pulse energy produces the break-down. The remaining part of the pulse passes a variable optical delay system, and serves as a light source for a schlieren system. In this way, single-shot schlierenphotos of laser sparks with life-times less than one nanosecond are obtained. For the study of later stages in spark development multiple exposure by a train of pulses is used. The above mentioned experimental arrangements are discussed in detail, the measurement of pulse duration by TPF and image converter is described, and some results about the plasma-behaviour are presented.

Technical photography, through such means as interferometry, Faraday rotation, and simple shadowgraphs, can provide significant data for understanding the absorption and transport of energy within laser produced plasmas. For plasmas produced by intepip, sub-vanosecond Nd laser pulses, one is required to study electron densities in the 10" to 1021 e/cc range, with density contour velocities of 106 to l0 cm/sec, and axial scale lengths of 1-20 μm. In this paper we describe the relationship between these plasma parameters and the requisite photographic system. We conclude that the system requires a probe wavelength in the middle ultraviolet, a pulse duration in the 10-100 picosecond regime, and large numerical aperture optics corrected for spherical aberrations. Results obtained at 2660 Å with holographic microinterferometry, Faraday rotation, and shadowgraphs are presented.

A pico-second single pulse which was extracted from a mode-locked dye laser was used for the background illumination for shadow and Schlieren photography of objects in laser-plasma experiments. Shock front propagation in transparent solid targets and blast wave propagation in the background gas, both of them being generated by 5ns/5J Nd-glass laser pulse, were photographically studied. The system had a temporal resolution of 5ps and a spatial resolution of 5μm.

The interaction of high-power laser radiation with material provides new interesting possibilities for the production of high pressures and temperatures causing heating, melting, evaporation, ablation and formation of dense plasmas. Experiments have been performed by using an electron beam preionized CO₂-laser delivering pulses with energies up to 30 J and pulse durations of about 5 ps. With this laser shock-wave formation inside different solid and liquid materials and the correlated phenomena of initiation and propagation of laser supported detonation-waves outside the target surface in the surrounding atmosphere were studied. l'wer densities are in the range of 106 to 108 W/cm2. Quantitative measurements, revealing the strength of the interaction, were carried out using high-speed photographic and cinematographic techniques, including a Cranz-Schardin-camera and a Beckman-Whitley rotating mirror streak- and framing-camera. In order to obtain highest time resolution during the initial phase of the interaction, an Imacon 600 image converter camera was used. Results are shown and evaluated for metallic targets and for materials which are trans-parent in the visible spectral range such as glass, plexiglass, water, and CS₂.

The results of the holographic investigation of the quality of fuel pulverization by automobile diesel injectors and of non-stationary gas dynamics fluxes in exhaust systems are discussed. The prospect of the use of optical holography methods for the high-speed processes research in diesels is shown.

The condensation of the bubbles ejected into a subcooled liquid is studied by means of high speed photographic shadowgraphy using a rotating prism camera with the speed of 3500 frames per second. The system pressures are parametrically varied in the range from vacuum to 10 ata and the subcooled temperature ranges from 10 to 70 deg. The picture shows that the penetration of an ejected bubble into the flattened lower boundary of the preceding bubble is most significant. The high velocity liquid jet is indicated by using tracers such as polystylene particles or condensed milk which was introduced in the liquid. From these results, it was confirmed that the average velocity of the liquid jet can be estimated quantitatively. Finally, the results from an experiment of bubble ejection into a narrow space between two glass plates is reported as a means to model the fluid motion two dimensionally. The penetration of the ejected bubble into the preceding bubble is clearly evident and it was certified that the effect of the penetration is very important factor for bubble condensation in a subcooled liquid.

Two types of high speed photogrammetry have been used to study the reflection of spherical blast waves from real and "ideal" surfaces. The spherical blast waves were produced by 500 kg charges. In each experiment two identical charges were simultaneously detonated, suspended one above the other so that the distance between them was twice the height of the lower charge above the ground. Observations were made of the blast wave from the lower charge as it reflected from the ground surface, and of the waves from the two charges as they interacted along the plane of symmetry between the charges. Since there was no energy loss in the interaction of the two waves, this could be considered as an "ideal" reflection. The refraction (shadow-graph) images of the shock fronts were photographed at 4000 pps against a 15 m high backdrop of black and white stripes. The positions of the shocks at regular time intervals were calculated and used to determine the shock velocities and thus the pressure, density and entropy behind each shock. On the other side of the charges an array of approximately 250 smoke puffs was generated. The puffs acted as tracers of the air flow within the blast waves and the 5000 pps photographic records of their positions were used to determine the particle velocities and densities throughout the waves.

This research is part of a study of the behaviour of high-velocity gas jets,particularly as regards their acoustic behaviour and noise generation. As a step towards understanding multiple jet configurations we have investigated a 2-jet situation. 2-D nozzles were designed so that they could be mounted side by side and operated separately. The nozzles could be moved by a vernier control from a separation of several centimeters till they were adjacent. Vertical motion of one jet and some rotation was also possible. The photographic approaches included a stroboscopic/TV method from which video recordings and a film were made and single flash high-resolution photography. Observation were made on the cell structure, oscillation phenomena and the way the two jets interacted both acoustically and aerodynamically.

Several kilojoule co-axial flash tubes and their 5-stage Marx generator are described. The maximum peak power input to the flash tubes is around 500 MWatts. Systematic time resolved measurements of flash tube characteristics for gas pressures from 20 to 210 Torr and for electrical pulses up to 80 KV are reported. Optimum E/p values have been obtained. Radio frequency preionisation was used, for the first time successfully in a flash tube, which resulted in the enhancement of the peak power output by up to a factor of at least 2 and the improvement of the flash tube operation. The dependence of the enhancement on the delay between preionising pulse and main pulse is analysed. Uniform discharges for E/p values as low as 10 volts/Torr.cm have been achieved for the first time in co-axial flash tubes using this technique. Advantages of this technique compared to previous pre-ionization techniques are considered. The system reported here appears to be superior in the following aspects: 1) Enhancement of peak output power, 2) Improvement of amplitude jitter of the flash tube output, 3) Life of the flash tube. Advantages of using such a system for high power lasers are discussed and comparisons with previous fast rise time co-axial flash tube systems are considered. The use of these flash tubes to pump iodine photodissociation laser and dye solutions is described.

A high-intensity self-shuttered point light source of coaxial configuration with restrained capillary is described. The principle involved is the use of an artifical transmission line with ignitron crowbar. The current and with it the light pulse can be clipped within the range 10-150 μsec to prevent double exposure in rotating mirror cameras. The onset of the light pulse is less than 2.5 μsec. The effective undesired afterglow amounts to about 3 iusec. The photoemission is fairly constant to provide uniform exposure density on film. The light output amounts to 3.5 x 106 candelas for a source diameter of 1.5 mm. The size of the point light source is stable both in axial and radial direction and prevented from flickering by a plexiglas disc which terminates the plasma and the conical aperture. The light source has been applied successfully for taking pictures of a 18 cm dia field of view in shadow-graph and interferometer arrangements using a Cordin high-speed framing camera model 330 at a speed of 2.5 p.seciframe.

The single or multiple spark gap COMBI SPARK serves for photographic recording of rapid events by means of either a single flash or of several time controlled spark gaps. When using a large size plate camera and superposition spacial separation of the object phases is effected by object movement. The instrument consists of spark head(s) and control unit. Firing of the flashes is effected over a retarder which can be steplessly adjusted over five decades. In case of multi spark gaps, the firing intervals between individual flashes can be adjusted independently from each other. The spark head contains triggerable spark gaps in coaxial design which are mounted in a pressure housing. Fillings with different gas mixtures can vary flash duration and light output. The COMBI SPARK can be employed both as front light or back light in motion analysis experiments in a wide variety of research fields, e. g. dynamic material stress, ballistics as well as shock wave investigations.

A photographic system of great simplicity is described which appears to have some advantages over conventional microscopic photography. The key element is a small-size light source of short-flash duration and considerable output. Two possible sources are described, (1) a guided air spark with an aperture hole, and (2) a xenon arc of small size. In addition to short exposure, because of the flash source characteristics, the ability of the system to cover a large area with high resolution may be useful. One inherent advantage of the silhouette system is depth-of-field at the subject. Two limitations are treated in this paper, the blur caused by an edge, and the light diffraction around a sharp edge. Theory shows that the definition and diffraction are both improved by a very close subject-to-film distance, as well as a small source size at a large distance from the film. Diffraction effects improve with shorter wave lengths of the exposing light, as is well known. There is some promise that the silhouette photography system may have advantages over the electron microscope since the subject need not be in a vacuum and; therefore, is not dead when studied.

The dynamic analysis of elements of mechanical systems is very important both from the operational aspect and from that of sensitivity to environmental disturbance. Thus determination of the transfer function T(jw) for the system under test is one of the most important aims of dynamic analysis. For an impulse at the input, linear systems respond their weight-function at the output with the Fourier transform of that giving the transfer function. All mechanical systems giving optically transformable translation as an output for an impulse at the input can be analysed using high-speed film recordings. We determined the transfer functions of electromechanical systems, to the elements of which transducers could not be fitted due to the disturbing effect of their mass. The characteristics of the weight-function and the shape of its spectra for the system under test can be estimated in advance; one can probably set a suitable duration for the recording, and the correct frame frequency to satisfy the requirements of Shannon's sampling law. After digitalisation the information stored in the film was processed by computer. The paper describes the applied measuring techniques, the experience gained, and the results obtained; some of the film shots recorded for analysis are to be presented for illustration purposes.

This report contains a description of a computerized spectroscopic data acquisition and analysis system used to analyze flare emissions and smoke absorption. The system enables the computer generation of system corrected and signal averaged plots of spectral radiant intensity versus wavelength in the case of flare emissions, and the generation of plots of transmittance versus wavelength as a function of time in the case of smoke obscuration experiments. The system consists of several commercially available components. A dual channel scanning spectrometer, presently set up for the 1.7 to 4.7 micrometer region, enables spectra to be obtained repetitively with scan times of 1, 50, 100, or 500 msec, and with a resolution (at the slowest scan times) of 0.004 micrometers. Two channels of spectroscopic data, a number of channels of radiometric data, and various synchronization pulses are recorded on a 14-channel analog tape recorder. The spectroscopic and radiometric data are then digitized, using as many as 2000 points per spectral scan per channel. System corrected, absolute intensity spectra are generated in the computer by calculations involv-ing the flare spectral data, spectra of a Globar source, and the radiometric data. The system is flexible in that a variety of gratings, filters, and detectors make it possible to use this system in the near ultraviolet, visible, near, and middle infrared.

The photochromic tracer technique is a flow visualization method, based on the introduction of a dark trace in a transparent liquid flow. This dark trace is formed as a result of the reaction of a photochromic indicator to an intense light flash. The light sources used are generally lasers, because they provide well-collimated light beams of high intensity in very short periods of time. The movement of the dark traces with flow is recorded on cine photographs, at up to 8,000 frames/s. Each subsequent series of frames contains the information describing the subsequent positions and shapes of the trace related to time. The photochromic tracer technique was described in detail by R.L. Hummel et al in series of papers (1,2,3).

This paper deals mainly with the results of observations by optical tracking which were done for the Japanese sounding rockets Mu-4S type series. We also introduce our optical tracking stations and apparatus used for the observations. 16mm movie films on the results of the earlier type series rockets Pencil, Kappa and Lambda which are still used were presented at the 5th and 9th Congresses on High-Speed Photography by Prof. Tsuneyoshi Uyemura. After that we have succeeded to put artificial satellites into their orbits around the earth using Lambda and Mu-series rockets. Mu-4 type rockets have diameters of 1.4m and lengths of 24m and are four staged rockets all stages of which have solid fuel motors, and the fourth stages carry the satellites. Six stations which are used for optical tracking for the Mu rockets are located around the Mu launcher, and in each station tracking apparatus such as various high-speed cameras are installed. We observed the rocket at the moment when it was just launched off and the behavior of the rocket after launching and during its journey, and also determined the trajectory of the rocket. The observation by the optical tracking system is performed in a completely separated manner from the rocket itself, and so we can continue observation even after the rocket happens to burst in an accident. Beyond this advantage the optical tracking method is at present the only method by which we can observe precisely the flying characteristics of the rocket in the early stage of its trajectory. On the other hand we cannot use the information other than the light emitted from the nozzle flame and the reflected light of the sun, and this means the trackability is deeply dependent upon the climate condition when launched.

The aperture for NASA's Space Telescope will be 2.4 meters. Although its form is conventional from an optical standpoint, it has substantial extensions of the state of the art, including provision for perfecting the optical figure of the primary mirror after it is placed in orbit, unique structural design and materials which render it immune to the severe thermal environment of space, and a pointing system which will control the direction of its line of sight to +0.007 arc-second (the head of a pin at 25 miles) for periods up to 10 hours. It will carry four or five science instruments at any one time, including cameras, spectrographs and photometers, all of which utilize electro-optical sensors, often operating in a photo-counting mode. Observational information will be transmitted to ground on a "near-real-time" basis through a data relay system which incorporates synchronous satellites and multiple ground stations. About 30 minutes of data will be available per orbit at a data rate of one megabit per second. There will be two on-board computers -- one to operate the science instruments and the other to operate the telescope. Command data is transmitted from the ground and engineering data transmitted back at a 50 kilobit per second data rate.

The technique described allows x-rays to be used to produce high-speed cine pictures of projectiles in flight and during target impact when surrounded by smoke, flame and intense light. A long pulse x-ray source together with a gated x-ray image intensifier is coupled to a high-speed cine camera permitting the production of sequential pictures at 22,000 frames per second, with exposure times down to one micro-second. Pictures of high velocity projectiles in flight are shown.

An Image Convertor Camera based on RCA C73435 tube with FO output window was built. Camera design is made on a modular base. A 25 mm microchannel plate Image Intensifier may be coupled to the Camera output by tapered FO cone with demagnification factor 2.5. Camera provides either direct (contact) or optical (lens) coup-ling to photographic film. Input optical heads are interchangeable for framing and streak modes. Internal power supply, power line input filter and proper body shielding ensure troubleless operation even in high-level EMI experiments. Interchangeable plug-ins form shutter and deflection pulses for 20, 50 and 100 nanosecond streak and single-frame operation. Camera will be used in experiments on Intense Electron Beam Accelerator at the Weizmann Institute of Science.

We have investigated the characterisitics of a number of different streak cameras (IMACON600, IMACON675, and Electrophotonics cameras). With the exception of image converter tubes of very poor quatum efficiency, all cameras show a smiliar intensity-dependent time resolution.

Some problems of digital image processing are discussed for pictures taken vith high--speed image-converter camera (ICU) in streak oDeration. Goneral asects of image proces-sing such as coding, filtration, restoration are briefly analysed. 'iathematical approach to the approximate estimation of an image-converter tube (ICT) response function is suggested. A solution for the restoration of images distorted by the IiT can be found by solving an integral equation (in terms of incorrectly formulated problem) describing the ICT imaging system. The regularization procedure for solution of this integral equation is described. Presented are some examples of the IT imar;e reconstruction on the basis of the developed image-transform technique.