Open grid vs mesh grid as the extraction field structure in a streak camera image-converter tube

It is concluded that the dynamic range of a streak tube does not depend on whether it uses a fine-mesh or an open structure to provide the extraction field. An RCA C-73435 streak tube body was fitted with two extraction grid structures by replacing the conventional open grid with a steel plate containing two apertures. One aperture simulated the open grid structure; the other was a 2 x 20 mm slit covered with a fine mesh (40 wires per mm, 38% transmissive). The apertures were equal distances above and below the tube axis. Using 35-ps pulses, dynamic range curves were taken at 1.06 ..mu..m on one aperture at a time, while blocking the other aperture. As we anticipated, the tube saturated at nearly the same point for the open and mesh apertures. The noise levels for both apertures were almost equal and very close to the film fog level. Noise level was lower than for earlier measurements on other makes of tubes with a fine-mesh grid. The dynamic range for both apertures was in the order of 6000, which indicates that the lower dynamic range of other tubes must be due to something other than the use of a fine-mesh grid