The 5RP Multiband Tube: An Intensifier-Type Cathode-Ray Tube for High-Voltage Operation

It is pointed out that, at the medium voltages employed in conventional cathode-ray oscillographs (3 to 4 kilovolts), full advantage cannot be taken of high-frequency circuit performance either by photographic recording or visual observation, due to insufficient trace intensity. A new tube, the multiband tube, is described which is essentially a high-voltage intensifier-type cathoderay tube. Its cylindrical shape and the subdivision of the intensifier electrode into several bands (multiband) reduce intensifier distortion to such an extent that the tube may be operated with good results at intensifier-to-second-anode voltage ratios of 10:1. A low-capacitance deflection system, with leads brought through the tube neck, makes it particularly useful for high-frequency applications, and its nearly flat face simplifies the lens problem for photographic recording and projection. The tube can be used as a replacement for 5CP tubes on standard equipment with little change, except the addition of an external intensifier voltage supply. Typical operation is at Eb2= 1500 volts, Eb3= 15,000 volts. Results are given and particular applications and modifications (projection, ultra-high-frequency tubes) are described.