A highly sensitive framing streak camera which works in two types of operation, framing and streak, with 3 plug-ins (framing, fast, and slow streak) has been developed. In both operations, a gate extinction ratio of more than 1:107 has been achieved by double gate operation at the photocathode and the built-in micro channel plate. The framing plug-in has a framing speed up to 3 million frames/sec, with the shortest exposure time of 50 ns. The frame number can be easily changed. Exposure time and frame interval time can be set for each frame, respectively. The fast plug-in offers temporal resolution of better than 10 ps in the fastest sweep range and 25 mm useful photocathode length. The slow plug-in provides time windows from 50 ns to 10 ms/40 mm in 17 ranges.

We have designed and built an x-ray streak camera with subpicosecond time resolution. This camera attains its fast temporal resolution through a very strong extraction field, 100,000 V/cm, at the photocathode. It incorporates a narrow electron emission band photocathode that will also help the time resolution. The total time resolution has been calculated to be near 600 fs.

The channel capacity is the number of bits of information that can be encoded in a single sweep of a streak tube. Imitating the standard practice for digitizers, this channel capacity could serve as a figure of merit for comparing the relative values of streak tubes. An expression for tube channel capacity is developed in terms of its main performance characteristics.

CSC (Containerized Streak Camera) photonic analyzers have been under development by Thomson-CSF/DSE/DT/S.ASI since 1986 on the initiative of CEA-DAM-BIII (Research Center at Bruyeres-le-Chatel) for the study of the multi-phenomena related to nuclear experimentations characterized by bandwidths of greater than 1 GHz. After a review of this analyzer's features, which are inherent to its use in container, and the necessity of digitizing and transmitting the data within the exceedingly brief time preceding its destruction, we shall take a look at the developments in CSC design and the two succeeding generations of hardware. The present version and its characteristics will be given in detail. The presentation of a few experimental results show that the bandwidths actually measured on the 15 measuring channels are of the order of 1.5 GHz over the entire sweep for an analysis duration of 30 ns. Our paper will end by the definition of the targets set for the third generation CSC, now under development.

The gains of gated MCPIIs at high repetition rate (up to 10 kHz) were measured. Comparisons were made between the gain behavior of a standard ITT type F4111 MCPII and similar device incorporating a high strip current microchannel plate. The most notable effect observed for the standard MCPII is a decline in luminous gain with increasing gate repetition rate and with higher input irradiances. The intensifier with the higher strip current microchannel plate (MCP), on the other hand, exhibited little or no reduction in gain for gating frequencies up to 10 kHz under similar test conditions (60 pJ/cm2 input energy density). The charge storage capacity and recharge time of the standard MCPII are most likely the limiting factors in its ability to maintain a constant gain at high repetition rates. The limiting effect of the recharge time on the MCP gain is calculated and compared to the actual measurements.

Basic properties of a new streak camera and its test results are reported. To intensify images on its screen, we employed modular G1 tubes, the LD-A-1.0 and LD-A-0.33, enabling magnification of 1.0 and 0.33, respectively. If necessary, the LD-A-0.33 tube may be substituted by any other image intensifier of the LDA series, the choice to be determined by the size of the CCD matrix with fiber-optical windows. The reported camera employs a 12.5- mm-long CCD strip consisting of 1024 pixels, each 12 X 500 micrometers in size. Registered radiation was imaged on a 5 X 0.04 mm slit diaphragm tightly connected with the LD-S- 10 fiber-optical input window. Electrons escaping the cathode are accelerated in a 5 kV electric field and focused onto a phosphor screen covering a fiber-optical plate as they travel between deflection plates. Sensitivity of the latter was 18 V/mm, which implies that the total deflecting voltage was 720 V per 40 mm of the screen surface, since reversed-polarity scan pulses +360 V and -360 V were applied across the deflection plate. The streak camera provides full scan times over the screen of 15, 30, 50, 100, 250, and 500 ns. Timing of the electrically or optically driven camera was done using a 10 ns step-controlled-delay (0 - 500 ns) circuit.

Properties of an electron-optical single-frame camera enabling gating duration of 100 ns are reported. Gating is performed using the type LD-F-5 image intensifier tube. To intensify images on its screen, modular Gen I tubes LD-A-1.0 and LD-A-0.33 providing magnification of 1.0 and 0.33, respectively, were utilized. If necessary, the LD-A-0.33 tube may be substituted by any other image intensifier of the LDA series, the choice to be determined by type and size of an image-sensing CCD matrix with fiber-optical windows. The reported camera employs a 11 X 7.5 mm CCD matrix with 576 X 360 pixels. The LD-F-5 electron-optical shutter is controlled using radio-polar rectangular 100 ns pulses with an amplitude of 360 V, front and rear edge widths of 15 ns, and top slope within 3%. The system provides dynamic spatial resolution of around 20 l.p./mm, which is slightly worse than static resolution. The dynamic range of the registered optical signal is of the order of 300. The LD- F-5 output was intensified by the LD-A-1.0 and LD-A-0.33 tubes, whereupon it was sensed by the CCD matrix and recorded into a buffer memory. Data processing and documenting were performed using IBM PC/XT/AT with an interface system of data transfer from the buffer memory.

Experimental data are presented that show streak tubes to be shot noise limited. A definition of dynamic range is proposed, which the author believes to be simple and useful. In accordance with this definition and the experimental results, an expression for the dynamic range of a streak tube is developed.

Future multibeam laser-fusion experiments will require that beam powers be determined with better than 5% precision over a range approaching 40 to 1. In this paper, statistical, dispersive, and nonlinear factors which most influence such measurements are discussed. We conclude that such measurements can be made with 30-ps temporal resolution using optical streak cameras.

The MTASC (Microwave Transient Analyzer by Streak Camera) is designed for diagnosis of single-shot transient signals with a very wide bandwidth (> 10 GHz). The microwave electromagnetic signals are measured either in the form of voltage or current, or an electric or magnetic field. Since these signals possess both a broad bandwidth and expanded dynamic range, a multi-channel photonic analysis system is needed. Only photonic analysis covers such a broad bandwidth, which will be extended to more than 30 GHz in the future. Given that a dynamic range of around 60 dB cannot be measured directly, it is split by the sensing system which converts it into parallel channels applied simultaneously on the photonic analyzer. At first, passive sensors will be used in the system; later, in order to increase sensitivity, active sensors powered through optical fibers will be used.

The use of streak cameras for high-precision (picosecond) temporal measurements is planned for the Geodynamic Laser Ranging System. This paper analyzes the streak camera parameters which affect chronometry resolution, and three feasible versions of a picosecond chronometry system for space mission applications. Out of the three, the electronosensitive camera is considered to offer the best trade-off with respect to performance, size, and weight.

Two fast framing TV cameras have been characterized and compared as readout media for imaging of 40 mm diameter streak tube (P-11) phosphor screens. One camera is based upon a Focus-Projection-Scan (FPS) high-speed electrostatic deflected vidicon with 30-mm-diameter PbO target. The other uses an interline transfer charge-coupled device (CCD) with 8.8 X 11.4 mm rectangular Si target. The field-of-view (FOV), resolution, responsivity, and dynamic range provided by both cameras when exposed to short duration (approximately equals 10 microsecond(s) full width at half maximum (FWHM) transient illumination followed by a single field readout period of < 3 ms are presented.

A new version of a streak tube (named SCANCROSS) is proposed, for studies of short light flashes aimed at the elucidation of temporal light flux energy distribution. SCANCROSS differs from the existing streak tubes in that the photoelectrons escaping the photocathode surface are gathered in an aberration-free crossover due to an electrostatic field formed by a 'quasi-spherical' electron-optical system. At the crossover output, the electron beam aperture is compressed, the electron beam accelerates, and is focused on the phosphor screen plane. The two principal advantages of SCANCROSS are a low threshold photosensitivity at preset temporal resolution, and a wide sensing dynamic range.

A holographic technique ('light-in-flight' (LIF) holography) is described, which combines classic off-axis holography with the latest ultrashort-pulse laser technology to produce three-dimensional images with femtosecond temporal resolution. The LIF holography can be used to study the distortions of pulses moving through optical fibers (Abramson, 1987), visualize relativistic effects (Abramson, 1985), measure the shape and deformation of fast moving objects, and make observations through nonrigid scattering media (Spears et al., 1989). The technique can also be applied in ultrafast optical science, metrology, and medical imaging.

This paper discusses the design of a multispectral radiometer and camera implemented using a CCD imager, two Silicon photodiode radiometers and a rotating filter wheel equipped with six bandpass filters spaced throughout the visible and near-IR spectrum. One of the radiometers has a field-of-view matched to that of the camera to measure integrated scene radiance, whereas the other radiometer functions as a spot radiometer to measure small surface radiances. The system is synchronized with the 60 Hz camera video and transfers the 16-bit digitized data from the two radiometers once every video field through a parallel interface to a video data encoder. The encoder incorporates the data into the current video field for VCR recording and later playback and analysis. The system is designed for airborne use mounted underneath the wing of an aircraft. Its main purpose is to analyze the spectral radiances of various surfaces involved in high-speed videography experiments. The data obtained with the radiometer will be used to refine specifications for a high-speed, high-resolution solid state imager. However, applications extend to any field where fast, spectral measurements are required. A data set obtained for a sample application is presented to illustrate the performance of the system.

Video motion analysis has entered a new era with the introduction of the Kodak EKTAPRO EM Motion Analyzer, Model 1012, a high-speed solid-state video recording system. No longer confined to the limitations of film or tape for high-speed image acquisition, the electronic memory solid-state recorder offers new recording schemes never before possible. The EKTAPRO EM Motion Analyzer can be manually controlled by way of the keypad, or set into trigger dependent modes to allow the actual application to control the recording. Trigger parameters include switch closure, sound, temperature, change in illumination, or a change in voltage. By writing over old frames with new, it is possible to have the high-speed video system in a continuous record mode and ready to capture an intermittent or uncontrolled event without the constraints of recorders that are dependent on consumable media. This paper will focus on innovative recording techniques (Record, Record-Stop, Record-Trigger, Record-On- Command, Burst-Record-On-Command, and External Sync) and how the world of high-speed electronic image recording vastly differs from conventional high-speed tape and film methods.

The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

The current method of munitions systems testing uses film cameras to record airborne events such as store separation. After film exposure, much time is spent in developing the film and analyzing the images. If the analysis uses digital methods, additional time is required to digitize the images preparatory to the analysis phase. Because airborne equipment parameters such as exposure time cannot be adjusted in flight, images often suffer as a result of changing lighting conditions. Image degradation from other sources may occur in the film development process, and during digitizing. Advances in the design of charge-coupled device (CCD) cameras and mass storage devices, coupled with sophisticated data compression and transmission systems, provide the means to overcome these shortcomings. A system can be developed where the image sensor provides an analog electronic signal and, consequently, images can be digitized and stored using digital mass storage devices or transmitted to a ground station for immediate viewing and analysis. All electronic imaging and processing offers the potential for improved data quality, rapid response time and closed loop operation. This paper examines high speed, high resolution imaging system design issues assuming an electronic image sensor will be used. Experimental data and analyses are presented on the resolution capability of current film and digital image processing technology. Electrical power dissipation in a high speed, high resolution CCD array is also analyzed.

A wing mounted flow visualization instrument for use in measuring in-flight aerodynamic parameters that are a critical influence in the performance of modern aircraft is described. These parameters include shock waves, vortices, and the location of boundary layer transitions. The instrument incorporates a rapidly scanned sheet of laser light projected from a pod which illuminates the flow region of interest. The instrument can be rugged, compact, light weight, versatile, operate from available aircraft power, and be easily integrated with existing test aircraft. Flow field data is extracted from the light scattered from the scanning laser sheet by aerosols in the flow field, and from light scattered by the aircraft surface. The results of an analytical study are presented based upon an idealized F-15 configuration which confirms that current laser and camera technology can elucidate and record aerodynamic structures of interest to researchers and engineers.

In an effort to increase camera readout speed, we have developed a nonconventional vidicon tube scanning technique. Because all vidicon targets are round, acquiring a full view requires overscanning with a conventional square format scan, resulting in 22% of the video field time wasted. Furthermore, conventional scanning employs horizontal flyback, which for high frame rates can be more than 10% of the total field time. Our nonconventional scanning technique eliminates flyback time by utilizing a triangular waveform rather than a sawtooth for horizontal deflection. This triangle wave is amplitude modulated in order to scan only the (circular) area of interest. The vertical deflection is a staircase ramp, with a step occurring at the end of each horizontal line. This maintains even spacing and a parallel relationship between horizontal lines, as opposed to skewed lines with conventional scans. To display the video output, the X-Y monitor must also be driven with these waveforms in order to maintain the correct temporal and spatial position of the video data. Sweep rates of 400 lines in a 1 ms field have been demonstrated. Test results using this technique show a frame time reduction of approximately 30%, with no loss of resolution or dynamic range, and no increased video bandwidth requirements.

The detection of low X fluences up to 10 MeV requires increasing the capabilities of the radiographic reception. The efficiency determination of a calcium tungstate screen film pair implies the energy deposition knowledge. For this purpose, a collaboration with the Atomic Physics Center of Toulouse has begun in order to improve the efficiency owing to a parametric study of the energy deposition in the calcium tungstate by means of a Monte Carlo type code of the interaction of ionizing radiation with matter. For the interpretation of the data, software on a VAX 11/780 has been created. The following results, given for 3.8 MeV photons (equivalent energy for the GREC generator), are outlined: (1) a significant increase of the energy deposition in the intensifying screen when this one has a metal screen (Pb; W) in front of it; (2) for the tungsten metal screen, it exits a boundary thickness beyond which the energy deposition does not increase. Moreover, the radial energy deposition leads to the energy spread and the resolution study.

The emergence of lasers opened a new epoch in optical diagnostics of fast processes in many fields, and in gas dynamics in particular (holography, holographic and speckle interferometry, etc.). However, as to classical optical methods traditionally applied in gas dynamics, these new light sources, side by side with numerous advantages, have a certain demerit. High spatial coherency of a laser beam leads to the appearance of speckle structure in an image obtained with the help of interferometers or schlieren devices, which cannot be eliminated even with scatterer application. A new semiconductor laser with electron-beam pumping is free from such a demerit. Its quality and capabilities are illustrated by a flow pattern obtained at a ballistic range.

In flash x-ray photograph, boundary judgement of image is very important in measuring the collapsing parameter of a shaped charge and the experimental verification of numerical simulation. Thus, image processing has been developed on the experimental research of shaped charge. An example is given. It is found that the contrast of the photograph becomes higher and that the boundary curve equations can be obtained by image processing.

Laser-launched, miniature, pseudo-one-dimensional flyer plates are evaluated by three distinct optical techniques that may be incorporated into an optical diagnostic system to give a complete understanding of the plate performance. These techniques are: velocity interferometry, streak photography, and pulsed laser stereo photography.

Dealing with dynamic behavior of solids, detonator initiation, shock and detonation waves and other fast processes implies a number of new techniques. We are working on wave propagation at velocities of several km/s, with states existing for only a few microseconds or even nanoseconds. In this case performances of our fastest rotating mirror framing cameras are not high enough to observe states of surface or large discontinuity zones (problem of dynamic blur). We have developed a new laser technique called Instantaneous Image (I.I.). This technique consists in recording a single image in a short exposure time to minimize the dynamic blur of our fast phenomena. We use a Q-switched Nd:YAG laser made of an oscillator, a pre-amplifier, a 16 mm diameter amplifier and a KDP crystal. The available energy is in the order of 200 mJ at 532 nm for a ten nanoseconds pulse duration. A large amount of work has been done to minimize the non uniformity of the delivered light, to eliminate speckle defects and to collect the most illumination light by an optimized optic device. Under these conditions a large diameter field image (D equals 200 mm) can be achieved with a resolution better than 15 line pairs/mm. With a double proximity focused microchannel plate image intensifier (M.C.P.) it is possible to obtain faster shuttered times (a few nanoseconds) with a higher gain to observe poor reflective surfaces. But under these conditions the resolution decreases drastically to some line pairs per millimeter.

In this paper, experimental results are presented of using a small pulsed YAG laser to ignite detonating powder to produce the temperature field of transient combustion, and of using a method of serial pulsed laser interferometry to obtain time series interferograms of the combustion process of detonating powder. By means of a computer, a detecting method of fringes thinning is used to thin the fringes of time series interferograms, and fringe displacements are read automatically. The transient temperature distribution of the combustion field of detonating powder and the changes of temperature with time in the combustion process are calculated quantitatively.

Pulsed CO2 lasers are the most powerful infrared source of coherent radiation. Volume self-sustained discharge (VSD) is the simplest and most convenient method of pumping. But the main problem of such laser construction is obtaining the VSD. The results of experimental investigation of the influence of stepwise ionization on the contraction basic mechanisms in CO2 gas mixtures are presented in this paper.

By using a Q-switched YAG laser and an optical path delay set-up, we study the process in which as laser induces breakdown to produce plasma in air. We obtained time-resolved Mach- Zehnder interferograms and optical shadowgrams of the initial stage of the plasma, and shock waves produced in the process are obtained.

United Technologies Adaptive Optics Associates (AOA) in conjunction with EG&G Reticon has developed a 500 Hz, 256 X 256 Pixel Camera System with a PC/AT controller and memory card. This high frame rate camera, the MC4256, is a turn-key solution to a multitude of high-speed imaging problems, applicable to medical imaging, machine vision, and real time inspection and analysis for manufacturing processes. The MC4256 system can control and store up to 1024 frames of 8 bit data.

Recent advances in high-speed microscopy allow successful streak photography of nonreactive shock waves passing through individual explosive crystals. Measurement of the shock velocity both in the crystal and in the water surrounding the crystal allows us to determine the shock pressures. These diagnostic tools have the required temporal and spatial resolutions to enable us to study the microscopic processes in nonreactive and possibly reactive shock environments.

When optimizing equipment in which 'fast grating' is used, it is important to discriminate between the 'speed' of the module and the speed of the electrical gate-pulse unit. D.E.P. has therefore developed a method to measure the speed of the module independently of the gate- pulse unit. D.E.P. measures, during the switching on of the module, the time delay between the center and the edge of the module, which we call the iris delay. Even with an electrical gate-pulse of 3 nsec rise-time, we can measure an iris delay down to 0.2 nsec. The shortest pulse-width for which a module can be used is about 2 or 3 times the iris delay. This measurement is done with a pulsed solid state laser. The laser is fired with a variable delay with respect to the gate pulse on the tube.

High resolution x-ray streak camera built around bilamellar tubes have been developed for a long time in CEL-V2. The C850X camera is the last step of those studies. We describe here the different versions of the camera; we also present the experimental results (temporal resolution approximately equals 2 ps in conjunction with a dynamic spatial resolution > 15 1p/mm) obtained in ENSTA on a 60 fs UV laser, which match our theoretical predictions. The improvement of the C850X electronics have also been implemented on C750X (the P750X tube of the camera has the same structure as that of C850X, but its deflection plates are replaced by a 50(Omega) meander stripline, which allows higher sweep speeds). We present the status of that development, the improvements accomplished on the sweep circuit, and the first results obtained with that device.

A 14-bit scientific CCD camera has been used as a medium-speed streak camera through software modifications that preserve the high dynamic range and excellent sensitivity characteristic of these cameras. Line shift speeds as short as 8.1 microsecond(s) ec are found to have no detrimental effects on image quality as long as light intensity is kept below saturation levels. Examples of streak images from shock tube studies of reactive systems are presented.

The modern electron-optical system (EOS) consists of electron-optical camera and a readout system under computer control. The characterization of the electron-optical system includes a sensitivity, dynamic range (DR), modulation transfer function and noise calibration. Instead of usual DR definition we propose a definition of useful DR (UDR) which is connected to the number of distinguished intensity levels. We also consider the CCD linearity and pulse FWHM estimation by Gaussian approximation. We propose computer techniques for the modulation transfer function estimation using a test source at different pulse energy. Examples of calibration of different systems are presented.

We have measured the modulation transfer function (MTF) of fiber-optic bundles (reducers), minifiers (inverting, electrostatically focused imaging tube reducers), microchannel plate image intensifiers (MCPIs), and streak tubes as part of our ongoing device evaluation program aimed at precise characterization of various imaging elements used in fast cameras. This paper describes our measurement equipment and techniques and shows plots of MTF measurements for each of four types of fast-cameras elements tested.

The atm of the present work is a search and investigation of efficient photocathodes for detecting ultrasoft X-ray and UV radiation. This research is urgent first because these photocathodes are widely used in image converter tubes (ICT) which are important tools for laser plasita diagnostics. These photocathodes are peculiar for their being able to be for some time in the air without changing the emission characteristics, though on a long-term keeping under atmospheric conditions their parameters are deteriorated for different reasons (oxidation, moisture absorption). Therefore, when preserved for a long time they should be kept in vacuum. Besides laser plasma diagnostics, an interest to ultrasoft X-ray and UV region of spectrum is also encouraged by research on excimer lasers, plasma in systems with magnetic retaining, VHF discharges, and many other physical processes associated with generation of X-ray and UV emission. An increase of photodetector quantum yield in this research is an extremely important task, since it is the photocathode that determines to a great extent the effectiveness of radiation recording. Our major purpose was a search and study of more efficient photocathodes for ultrasoft X-ray and UV regions.

We have developed a fiducial system for rotating mirror streak cameras that utilizes light emitting diodes mounted at the slit position of the camera. The diodes are driven to the required high brightness by a unique pulse power circuit designed to provide high voltage, high current pulses 18 nanoseconds in length at a frequency of up to 2.5 megahertz. The availability of super bright light emitting diodes with a wavelength of 630 to 640 nanometers allows us to record fiducial pulses, at streaking speeds in excess of 20 mm per microsecond, on all the black and white films commonly used in high speed photography. The time marks on the film record are references to the real time of the experiment from a clock-driver that controls the start and frequency of the fiducial pulse train and by three adjustable and discreet blanked fiducials. This paper discusses the development of this system and describes the full setup as used at LLNL.

We have developed a system which allows repetitive events at frequencies up to 4 kHz to be imaged without aliasing. An off-the-shelf optomechanical imager (Inframetrics IR 600) is used in conjunction with a microcomputer and a specially developed hardware interface. The effective integration time of the system is equivalent to the horizontal line scan time (125 microsecond(s) ). Images are constructed by acquiring horizontal lines which are in phase with a reference signal emanating from the target. Multiple occurrences of a given line are displayed as a linear average so that the in-phase component appears amplified in the final image. Images of flame front propagation in an operating engine combustion chamber, and transient spatial heat distribution in a transistor operating at 2.5 kHz have been acquired.

An x-ray streak tube (XRST) for soft x-ray (0.1 - 10 keV) research and a streak camera with the XRST as a part of it are described. The streak tube is attached to a radiation source chamber, operating at 1 Pa pressure, via a pumping-out device with an ion pump, which provides operating pressure of 10-4 Pa in the streak tube. The pumping-out speed is 6 1/s. The pumping-out device has an inspection window through which changeable Au, CsI and CuI photocathodes and a cassette with a film (which separates the volume of the radiation source chamber from that of the streak tube) are installed into the streak tube. Production technology of these photocathodes and their characteristics are discussed in the paper. The streak camera operates in remote and manual control modes and has discrete sweep duration values in the 5 - 500 ns range. The image from the output screen of the streak camera is recorded by a contact type camera or a TV read-out system. The possibility of sweep duration values calibration directly before making measurements is provided in the streak camera.

A new idea based on the sampling transform for measuring very short time jitter of e1ec trical ultra fast pulses is presented in this paper. It is shown that the measurement of a very short time jitter may be replaced by the one of a low level and low speed waveform.