The CV220 is a cold cathode four electrode neon discharge tube capable of producing very short duration pulses. The prototype is the 631-P1 and commercially it is the Ferranti NSP1. The circuit in the data-sheet suggests that the main use was in a stroboscope to inspect rotating machinery.
The KB/RC identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the RC identifies the maker as Ferranti, Chadderton, Oldham.
The anode at the top is supported by an insulated rod to ensure that the discharge is vertical.
The cathode and grid assembly in the centre.
The wide glass tube envelope is 29 mm in diameter, and excluding the UX4 base pins is 89 mm tall.
