Oil Immersed Low Power Tubes

           Hot-cathode 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 early 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.

Bare anode centered

by the Tungsten target.

Hooded anode. See the

target deep inside.

Hooded anode with

Beryllium window.

Note the “lead jacket” around the

middle part of this Machlett  tube,

seen in the lower right  corner  of

the group picture above