line-focus tubes of different sizes, shapes and makes, oil
immersed, ranging in output from 50 kV and 5 mA for the smallest, to 90 kV and 20 mA for the bigger ones,
used in dental units or low power portable x-ray equipment. Since the introduction in 1920 of the CDX shock-proof oil-immersed dental x-ray unit by
General Electric, and since the advent of the line
focus tubes in the twenties, the basic structure of these tubes has
not undergone any major changes.
Note the three types of anodes
used in the different tubes :
- the bare anode, with the
visible tungsten target.
- the hooded anode intended
to limit the x-ray beam and limit the
effect of “off-focal” radiation;
- the hooded anode with a beryllium
window, adding some filtration of soft x-rays.