What is this from? Big button HV connector. Pin voltage notes like an engineering model. Second note about two layer blue/yellow phosphor coatings. Pin 7 missing but shown in drawing.

http://www.ebay.com/itm/Rare-Vtg-GE-General-Electric-TV-Television-Glass-Picture-Tube-GL-12GP7-Electron-/151134940434?pt=Vintage_Electronics_R2&hash=item2330582d12

Probably Radar. G7 phosphor is short persistence blue + long persistence yellow. So they would sweep the screen to show the angle of the radar beam which would show up as blue and increase the beam current on the spots on the screen where an aircraft is so those spots would stay on until the next sweep as yellow.

Yes, it's a radar CRT. I picked up a couple very similar 12FP7s from fair radio sales years ago. 7JP4s look puny next to them :)

http://farm3.staticflickr.com/2726/4372034312_fab15166a5_z.jpg (http://www.flickr.com/photos/70039806@N00/4372034312/)