A camera-tube diode-gun with very small beam divergence

A diode-gun having a special beam-defining aperture is proposed. The measured beam-divergence angles were 0.3-0.65° in the range of 10-25 V of G1 voltage, and the current-density profiles showed a steep edge. A camera tube using this diode-gun gave high-resolution characteristics with amplitude responses of 58 percent at the center and 47 percent at the corner, at 600 TV lines in the normal scanning area of the 1-in tube.