“Okco” Hot Cathode Tube

Ref. C5

Made by the Otto Kiesewetter Company, in Germany, this is a typical Coolidge type X-ray tube of the twenties. 20” (50 cm) long, four-inch (10 cm) bulb, cooled by a heat radiator mounted on the anode shaft protruding out of the glass tube.

It has a flat spiral filament inside a cup reflector and a heavy copper anode with a tungsten target.

Before the advent of the “Line Focus” design, the 6 KW output of this tube was about the maximum to be expected from an X-ray tube.

By comparison to early Coolidge tubes, with large 6-8” (15-20 cm) bulbs, this type of tube was sometimes referred to as “Baby Coolidge”.