This is a Raytheon CK1383 "dual-gun cathode ray recording storage tube" circa 1963. This is a advanced design of an early (before core memory) approach to data storage called a Williams Tube. While used in some early computers, the original Williams Tube approach had many drawbacks: among these are very short data retention, destructive reads, and cannot read and write at the same time.
The device shown here solves these issues: it has long retention times, reads are not destructive and it is capable of simultaneous read and write. The datasheet for this interesting device is very informative.