Destructive readout in image tubes.
In conventional analyses of the readout process in image tubes, the scanning electron beam is described by means of a passive aperture function. Since the generation of an output signal depends upon neutralization of stored positive charge elements by the electron beam, it is clear that the beam's action is not passive. A progressive diminution or erasure of the stored charge density accompanies the progress of the electron beam. In this paper, a simple linearized model of the readout process is developed which incorporates progressive erasure of the stored image. Sample calculations are presented for the case of point targets. The analysis discloses three principal effects of image erasure: (1) the output signal corresponding to a point target appears on several successive raster lines with an asymmetric variation in strength; (2) the output signal derived from a symmetric charge pattern on the storage target is asymmetric in time along a single raster line; (3) the output signal reaches its maximum value before the center of the electron beam reaches the peak of the stored charge pattern.
Miller
A
A
Physics Department, New Mexico State University, University Park, New Mexico 88070, USA.
Lzatt
J R
JR