The Tektronix 154-0644-xx is a cathode-ray tube used in instruments specified up to 500 MHz. Suffix -05 has green P-31 phosphor, suffix -09 has blue P-11 phosphor.
It has distributed deflection plates. A domed scan-expansion mesh between the deflection plate structure and the accelerating anode provides both isolation and a two-times deflection magnification.
Typical acceleration voltage is 24 kV (−3 kV on cathode, +21 kV on post-acceleration anode).
As used in the 7904, the 154-0644-05 CRT has a deflection factor of 3 V/div and an impedance of 385 Ω.