Image Converter Tube Research Articles

A high-frequency discharge in an image converter tube

A glow discharge is described which has been observed between the rf excited deflection plates of a high vacuum imaging tube developed at THORN EMI, Electron Tube Division. Light emitted from the glow leads to serious deterioration of image quality. Possible causes of the discharge have been investigated by applying voltages up to 9 kV dc and 300 V, 100 MHz to the deflection plates and making observations of light output and dc pre-breakdown currents. The results have been interpreted using a model based on secondary electron resonance (multi-pacting) between the surfaces of the deflection plates; this produces a population of oscillating electrons. These electrons have long free paths and a significant probability of exciting low work function residual gas molecules. Methods of suppressing the discharge are discussed and include reducing the level of residual cesium, electrode coatings to suppress secondary electron emission and the application of electrostatic or magnetostatic fields.

Fast Beamprofile Measurement

The paper deals with a set-up utilizing synchrotron light which allows a fast measurement of beam width and beam height. The most important component of this device is a combination of an image-converter tube with an electron multiplying dynode system. The scan velocity is between .1 and .3 mm/μs and could be made even faster. This makes possible the measurements of acceptance, beam emittance, dynamical change of beam position and change of transverse beam dimensions during an accelarating cycle in an electron synchrotron. The device has also been used to measure fast cross section changes in the PETRA storage ring.

28. The design and performance of an ultrasonic image converter tube with a plastic faceplate and sensor

28. The design and performance of an ultrasonic image converter tube with a plastic faceplate and sensor

Raman lidar for analysis of industrial atmospheric pollutants

A Raman lidar has been developed for remote analysis of industrial plumes. The first test results were obtained. The Raman spectrum was excited by the fourth harmonic of a YAG laser. The signals received were recorded by a multichannel system which counts individual photoelectrons. A UMI-93 image converter tube combined with an isocon television camera tube or three FEU-106 photomultipliers were used as the light detectors. The gases SO/sub 2/, CO/sub 2/, N/sub 2/, O/sub 2/, and H/sub 2/O were recorded in a plume from a thermal power plant at a distance of 200 m. For a signal-to-noise ratio of 2, probed layer 22.5 m thick, distance of 100 m, and measurement time of approximately 3.5 min (10/sup 4/ laser pulses at a repetition frequency of 50 Hz), the sensitivity was 50 ppm.

Real time linewidth measurement of a continuously tunable multiatmosphere TE CO 2 laser

Frequency upconversion as a means of investigating the spectral characteristics of continuously tunable multiatmosphere TE CO 2 lasers has been demonstrated. Phase matched mixing in proustite of 10 μm laser radiation and the output of a single-mode Nd:YAG laser has permitted Fabry-Pérot interferograms, at the 0.96 μm sum frequency, to be recorded with the aid of a conventional image converter tube.

Recent developments in underwater imaging using the ultrasonic image converter tube

The Sokolov ultrasonic image converter provides a simple real time imaging system capable of good resolution and range in turbid water conditions. The tube is operated with anode potential target stabilisation and capacitive signal collection. Spurious signals at the ultrasound frequency are generated because of the stray capacitance of the scanned quartz surface. These signals are separated by modulating the electron beam at a different frequency and employing a head amplifier tuned to the intermediate frequency. Displayed images are free from fringes due to spurious signals and are unaffected by Doppler frequency shift. Factors which affect the resolution of an ultrasonic visualisation system are discussed.

Calibration and check of radiation pyrometers for the near-infrared region of the spectrum by means of standard temperature-calibrated lamps

Photoelectric radiation pyrometers for the 0.8–1.3-μ range and visual pyrometers with image converter tubes can be calibrated and checked by means of ordinary standard temperature-calibrated lamps with a tungsten filament equipped with a filter of 4-mm-thick SZS17 glass and 0.5-mm-thick NS6 glass. 2. For use as a standard source the lamp with the indicated filter should be preliminarily calibrated to brightness temperatures at any wavelength in the 0.8–1.3-μ range. 3. The described method of checking was adopted by GOST 18967-73 “Visual Micropyrometers with a Disappearing Filament. General Specifications,” and also GOST 8335-74 “General Industrial Pyrometers with a Disappearing Filament.”

Performance testing of electrostatically focused uv–visible image converters with deflection capability

Two prototype uv to visible image converter tubes with image deflection capability, produced by the En- glish Electric Valve Company, Ltd., have been tested with respect to performance parameters related to the photometric and imaging properties of the tubes. The two converters were electrostatically focused with a triode structure and were magnetically deflectable. The tests were executed at a facility for abso- lute intensity calibrations in the visible and vacuum uv spectral region available at the Max-Planck-Institut für Extraterrestrische Physik. Test procedures and results are reported.

Image-converter pattern tracker for variable retinal feedback experiments.

An optoelectronic device able to change the gain of the retinal feedback path from its natural value (−1) to any other value in the range −5, +5 is presented. The employement of an image-converter tube with coupled magnetic deflection circuit allows a large variety of targets to be used. Any type of artificial movements, moreover, can be imposed to the target itself. The device can be driven by any eye movement detector able to transduce the horizontal and vertical components of the eye rotation in the form of electrical signals. Experiments were performed to investigate the effects of varying the gain of the retinal feedback loop on the eye behaviour. Evidence was found for the existence of a range of values of such gain where the eye goes into spontaneous smooth sinusoidal-like oscillations. This phenomenon was examined with the control theory methods in terms of stability of the pursuit system. A correlation between the spontaneous oscillations and the well known learning capability of the visual system was found.

On the monitoring of laser radiation at 1.06μm

The design of a holder for an image converter tube, which is easy to construct in any university or laboratory workshop, is described. The performance of the system for monitoring the energy density distribution of laser beams at 1.06 mu m and in recording the spectra of neodymium systems is presented.

Laser Ranging System with 1-cm Resolution

A laser ranging system has been developed in which an image converter tube equipped with deflection plates is used to make a precise measurement of the fractional amount by which the time of flight of the ranging pulse exceeds an integral multiple N of the period of a stable oscillator. The value of N is determined in an auxiliary measurement. In short-range tests with a laboratory breadboard version of the system, time-of-flight uncertainties of about 45 psec were observed. The corresponding uncertainty in a range measurement is smaller than 7 mm.

Operation of a Grid-Shuttered Image Converter Tube in the Picosecond Region

Experiments have been carried out to investigate the performance of a standard, commercial, image converter tube (RCA C73435) in the picosecond region. Using a multikilovolt subnanosecond-rise time pulse generator, switched by a laser-triggered spark gap, to generate the deflection pulses, streak velocities of 1.6×1010 cm/sec and a streak-limited resolution of <5 psec have been obtained. Photocathode saturation and space charge effects are avoided with the use of low cathode currents, and, in order that photographic records can be obtained on high-speed film, a high-gain (106), four-stage magnetically focused image intensifier (EMI 9694) is optically coupled to the screen of the image converter tube. The over-all response time of the camera is also dependent on the transit time spread of the photoelectrons between the cathode and the screen and this is reduced by the application of accelerating voltages of 2500 V to the ICT grid. Evaluation of the camera system has been undertaken with the 1.06 μ fundamental output of a mode-locked neodymium glass laser. Mode-locked pulses of ∼6 psec duration were resolved.

Multiple Frame Image Converter Unit with up to Seven Frames per Trigger Using Solid State Design

Driving the RCA 4449A/C73435Q electrostatically focused image converter tube, the unit provides seven screen pictures of 25 mm height and 8 mm width in time intervals of 1–110 μsec and with 0.1–10 μsec exposures. The solid state circuitry generates +275 V p-p shutter pulses with 25 nsec risetime and a correctly timed balanced staircase waveform of 2400 V p-p.

IMAGE-CONVERTER STREAK CAMERA WITH PICOSECOND RESOLUTION

A streak camera incorporating a standard, readily available, image-converter tube has been developed and used for the direct measurement of 1.06-μ-wavelength picosecond pulses generated by a mode-locked neodymuim: glass laser.

Image-Converter Tube Camera with a Nanosecond Control System

Image-Converter tubes such as the electron-optical transducers PIM-UMI <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> have a limiting time resolution of about 3 ps which is limited only by the time of establishing the electron image in the plane of the screen. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> This time resolution was obtained in experiments with circular scanning of the image from miniature spark discharges. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> However, circular scanning has not found broad application in the field of physical experimentation, and the method of linear scanning of a slit aperture is now used for studying high-speed processes. Maximum time resolution of electron-optical transducers is reached for a scanning time of 1 to 1.5 ns; pulses of such duration can be applied to the control plates of the electron-optical transducers, the resonance frequencies of which are about 250 to 350 MHz.

A piezoelectric power supply for an infra-red image converter tube

A circuit has been developed enabling a hand operated piezoelectric high voltage generator to be used to operate an RCA 6929 image converter tube, using only five basic components - generator, diodes, spark gap, capacitor, and image converter. The complete system has been successfully incorporated into an infra-red telescope, which is independent of batteries or external electrical supplies, and has the additional advantages of cheapness, simplicity, and reliability.

716. Contrast fluctuations induced by ionic feedback in image converter tubes: A Fryszman and B Paszokowski, Bull Acad Polan Sci Sér Sci Tech, 15 (9), 1967, 817–821 ( in English)

716. Contrast fluctuations induced by ionic feedback in image converter tubes: A Fryszman and B Paszokowski, Bull Acad Polan Sci Sér Sci Tech, 15 (9), 1967, 817–821 ( in English)

An Underwater Acoustic “Television” System

It may not be widely known that, over the period 1949–1954, an experimental model of a closed-circuit underwater acoustic “television” system for use in muddy water, was developed in the United Kingdom under an Admiralty contract. The object to be viewed was irradiated with ultrasonic waves and a real acoustic image of the object was formed by a concave mirror. A special converter tube, rather similar to a television camera, transformed the image to a television picture. Two programs of work were pursued side by side: (a) the development of the image converter tube and electronic circuits, and (b) the design of the mirror assembly. Subsequently, the whole system was subjected to detailed investigation in a water tank and at sea, to determine the resolution, the maximum range obtainable and the appearances of a number of objects having simple shapes.

An electronic to ultrasonic image converter tube

This article describes in detail the elucidation of an equivalent RF-circuit diagram for an electronic ultrasonic image converter tube, and discusses practical aspects of the construction of the tube itself.

An electronic to ultrasonic image converter with enlarged image field

Most electronic ultrasonic image converter tubes suffer severe limitations which preclude their use in technology. This article describes ways in which these limitations can be overcome, and an efficient image convertor tube produced.