Abstract :
The purpose of this instrument is to facilitate the observation and recording of objects moving at very high speeds and events taking place in extremely short times. In particular, it is intended to enable very fast repetitive motion to be observed stroboscopically, and such transient phenomena as burning high explosives to be recorded photographically. The equipment described has been designed in conjunction with an experimental image convertor tube (a development of type ME1201), and is intended as part of a comprehensive unit to exploit inherent capabilities. The static conditions necessary for focusing are discussed. Using the method desciibed, a resolution of 20 television lines/mm can be obtained at the image on the screen, with an electronic magnification variable between ×4and ×3/4. The focusing system used enables an erect image to be formed at certain magnifications. The arrangements for controlling the photographic exposure are described. Two alternative arrangements are available. The first is aimed at providing the shortest possible exposure for transient events; an effective shutter opening time of 1/20 microsec has been reached. In the second system, for stroboscopic observation, exposures down to one microsec are available at repetition rates up to 100 kc/s. In some applications a time-scale is desirable. This can be provided by moving the image across the screen at a known velocity. Three methods of producing a time scale in this manner are described. By these means writing speeds on the screen varying between 10 mm/sec and 90 km/sec can be obtained. The slower deflections, up to 500 m/sec, are virtually linear with time, while the faster speeds are obtained by using portions of either a continuous or damped-train sinusoidal deflection. Finally, some of the further developments of the equipment are reviewed, which preliminary experiments have suggested as being both possible and desirable.
