Tube with Bauer Regulator (ca. 1912-1915) |
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The only markings on this tube are "2051" stamped on the target
and "1441" etched on the glass arm housing the cathode. The
overall length is 21" and the bulb is approximately 7 1/2" in
diameter.
Although the tube came from England, the regulator that it employs indicates that the tube was produced by Heinz Bauer, a German manufacturer of x-ray equipment. It is this regulator that makes the tube unique. |
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| The Bauer regulator (photo above right and diagram to right) was first described in the January 1907 issue of the Journal of the Rontgen Society. Its job was to "soften" the x-ray tube, i.e., increase the pressure of the gas inside the tube. Most regulators do this by heating up a chemical. The Bauer regulator is unusual because it employs a mercury valve that is operated with a rubber bulb - the bulb would be connected to the opening on the right end of the regulator. | 
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| Squeezing the bulb would push a column of mercury down a
glass tube inside the regulator so that a small opening in the tube is
uncovered (the opening is normally covered by the mercury). When the
opening is uncovered, a little air is allowed into the tube. Simple. The
diagram above right is a modified version of a drawing in GWC Kaye's X-Rays.
An advantage of this device is the fact that it allows the tube operator to adjust the tube pressure from a distance. The anticathode (entering the bulb from the right in the top photo) has a glass jacket extending most of the way along its length. This is to prevent stray electrons from striking the side of the anticathode and producing x-rays. If this occurred, the x-ray images would be somewhat blurry because the x-rays would be originating from too large an area. At least in theory. References GWC Kaye. X-Rays. Longmans, Gree and Co. London. 1929. H. Bauer. Improvements in Regenerative Devices for Apparatus for Producing Rontgen Rays. British Patent. No. 15,171. December 1912. (Patent kindly provided by Prof. Jean-Francois Loude). |
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