Fig. 1. Schematic of the pulse-dilation framing tube

Fig. 2. Diagram of lenses arrangement. (a) Four lenses; (b) triplet lens; (c) bilens; (d) simple lens

Fig. 3. Schematic of B distribution on the axis of drift zone of four lenses frames

Fig. 4. Three-dimensional fitting diagrams and two-dimensional coordinate distribution of imaging field curvature. (a) Simple lens; (b) bilens; (c) triplet lens; (d) four lenses

Fig. 5. Photograph of experimental device

Fig. 6. Experimental result of the center cathode image with four lenses

Fig. 7. Enlarged views of some clearly mask with 2 lp/mm and 5 lp/mm

Fig. 8. Diagram of the spatial modulation system of mask varying with r