Villard
Tube (ca. 1900) |
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10”(25cms) long, 4”(10cms) bulb. Concave aluminum cathode. Platinum
anti-cathode (with a visible central focal spot). Flat disc anode. Made by Emil
Gundelach, bearing the DRP (Deutsches Reichspatent) No. 103100 dating
back to 1898. Basically similar in design to the “Bulbar
Focus Tube” described earlier, with
the addition of a regeneration device using Paul Villard’s osmotic method. Note the platinum wire electrode terminals looped around the neck of
the small copper dome-shaped external connections of the tube (picture
above, right). This regeneration device, introduced by Paul Villard (1860-1934) consists of a small capillary platinum (or
palladium) tube, closed at the external end while the other end is sealed
through the glass wall and communicates with the cavity of the x-ray tube.
With use the gas pressure inside the tube drops down and the tube becomes
“hard”, needing a higher voltage to operate. By heating the external part of
the capillary in a flame, gas diffuses through the capillary into the tube
and restores the correct pressure. The external part of the regeneration
device is usually seen protected by a small glass test-tube. |
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A similar tube pictured in a 1901 Catalogue
of Siemens & Halske A.-G.
(Price:
21.5 Marks) |
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