That's a DeForest  DL4 next to it for
size comparision
Raytheon 8602/CK1383A
Recording storage CRT

This is a storage and scan-conversion tube, not specifically intended
for computer use but could be used that way.  It's a variant of
the 7702 (7702 offers either magnetic or electrostatic focusing;
this one offers only magnetic).  It can be written-into, then will hold
the information for hours and provide thousands of readout
scans.  Has separate "write" and "read" guns. 
Typical use was "slowing-down" of radar video for transmission over phone lines.
This is an analog device with 1200 lines of resolution, so
in digital terms it was in the megapixel range, each pixel had
a shades-of-gray capability, which nominally
expands the equivalent digital capacity a lot more.