This exhibit is a CV320 CRT the prototype was the CV967. The original buff paper label has been lost but the CRT arrived in an labelled paper bag. The device is a E4103/B/4 GEC experimental tube. The face is sensibly flat for 30 mm diameter.
Both anodes are connected together and need 800 Volts on them. With 800 Volts on the anodes the Y sensitivity is 0.09 mm/V and the X sensitivity is 0.1 mm/V. The grid voltage of -25 Volts is to achieve cut-off.
The detail picture shows the electron gun and Y deflection plates. The precision nature of the assembly is clear. This is why for television the easier to manufacture magnetically deflected tubes were chosen and developed.
The screen has a green trace.
The standard B9 base employs split pins for good contact with the socket.
Thanks to Patrick Atkin for spotting this CRT at a boot fair and donating it to the museum.
The end window envelope is 38 mm in diameter, and excluding the B9 base pins, is 138 mm tall.
References: Datasheet & 4018. Type CV320 was first introduced in 1936.