In the summer of 1950, I was working at Holmdel, part of Bell Labs. My job was checking the attenuation and phase velocity of the 49 modes above X-band cut-off in a several hundred foot length of 6 inch circular wave guide.
The point of these tests was to check the possibility of using a 2" WG at K-band frequencies to get the bandwidth required for the "Picture Phone" being hyped by AT&T. I used a Tek scope with direct connection to the deflection plates.
I complained to a friend in the Bell tube department that there ought to be a way to get better sensitivity. Moving the plates closer together and bending them apart at the beam exit might work. We took a spare 5" CRT apart, moved and "bent" the deflection plates, put in a new cathode and re-activated it. It gave about twice the sensitivity. Some time later I noticed the new Tek scopes had CRTs using the "bent" plates.