Leaded Glass Bowl (ca. 1920s, 1930s)

This is a leaded glass "protection" bowl of unknown manufacture. Although it is of an open configuration and designed to house a "universal" type Coolidge tube, the photo shows a radiator type Coolidge tube (which would normally be housed in an enclosed shield rather than an open one). The "universal" Coolidge tube controls its temperature by radiating heat through its large glass bulb. That is why its shield has to be open. An enclosed shield would cause the "universal" tube to overheat.

Quoting the description of an identical device in a 1922 Fisher & Co. catalog:

"Made of moulded glass, containing about 50% lead, affording excellent protection to the operator. Large enough to accommodate either 6" or 7" X-Ray Tubes. This bowl is furnished on our Compression Stand No. 1005."

A Thompson & Plaster Accessories catalog of unknown date describes the Fischer unit as follows:

"The Protection Bowl is built of heavy Lead Glass, affording ample protection. The X-Ray Tube is held firmly in the bowl by double action clamps which are self-centering and quick acting."

The bowl's metal base would be connected to an arm that was attached to a stand as seen in the accompanying illustration. In most applications, a lead lined cone would be positioned beneath the bowl to collimate the beam.

Of course, there was X-ray leakage out the top and ends of the bowl—it wasn't a particularly good design. On the plus side, the leakage out the top would produce beautiful colors in any ceramic lamp shades above the unit (Dale Trout. Vignettes of Early Radiation Workers).