Digital Memory in Barrier-Grid Storage Tubes

Storage of information in barrier-grid tubes is accomplished by depositing an electrostatic charge pattern on a dielectric sheet with a cathoderay beam and detecting the charge pattern at a later time with the same beam. This type of tube obtains its name from a fine grid placed immediately in front of the dielectric sheet. The "barrier-grid" serves to inhibit the redistribution of secondary electrons emitted from the dielectric sheet and to shield the drift space from electrostatic disturbances which would otherwise result from the stored charge pattern and the application of writing signals. Use of this type of tube for "image" storage was described by Jensen and others. This paper describes the characteristics of a barrier-grid storage tube when used as a memory device for binary digital information. 1 2 A. S. Jensen, J. P. Smith, M. H. Mesner, and L. E. Flory, RCA Review, 9, pp. 112-135, March, 1948. A similar tube was described by R. B. DeLano, Jr., Convention Record of the I.R.E., Part 3, pp. 125-130, 1954. 1 2