Chabaud Tube

Ref. B9

This cold cathode tube by Victor Chabaud is 14” (35 cm) long with a four inch (10 cm) bulb and an engraved inscription “V. Chabaud, Paris, No.803”.

The date of manufacture uncertain, but could be traced back to probably around 1905. Regeneration is by the Villard osmo-regulator.

This tube has only two electrodes, the aluminium cathode and the platinum anode serving as an anti-cathode.

Note the peculiar conical shape of the anode structure, with the flat target on the posterior internal wall of the cone, facing a round anterior opening through which passes the electron beam. The generated X-rays come out of the cone by its wide inferior opening. This tube is probably the oldest known with a hooded anode.

“ … Of the tubes with small bulbs, that of Chabaud is probably the best. The bulb is about 4” diameter.…..is made with great care in every respect, and all metal parts, excepting, of course the cathode, are made of pure platinum. It is provided with an osmo-regulator which can be warmed while the tube is working, and so long as its maximum current is not exceeded, it can run continuously for hours. Though the first cost is high, in practice it is one of the most economical and reliable. It is admirably adapted for X-ray treatment, and radiography of the thinner parts of the body. The remarkable feature of this tube is that in normal conditions of working - passing about 0.5 milliampere when new, but rather more when old - the anode is at a red or nearly white heat, and shows little tendency to get softer with the increase of temperature”.

(Edward Reginald Morton - “A Textbook of Radiology”,  1918,  p.50)