GB108793A - Improvements in and relating to Electrical Discharge Devices. - Google Patents

Abstract

108,793. British Thomson - Houston Co., (General Electric Co.). Dec. 6, 1916. R÷ntgen-ray t u b e s ; v a c u u m tubes. -- In a R÷ntgen-ray tube, hot-cathode rectifier, or other tube, having a container which comprises a conductive section and an insulating section, a device is provided to prevent accumulation of a charge near the joint In one form of R÷ntgen-ray tube, a copper section 1 and a glass section 2 are joined by a platinum ring 3. From the copper section 1 a copper sleeve 6 extends into the glass section 2. Negative ions entering the narrow space between the sleeve 6 and the glass are collected by the positivelycharged sleeve. A tungsten filament 7 forming the cathode is connected to a central wire 9 and a molybdenum focussing-ring 8, supported by wires 10, 11 from a split cylinder 12 of iron or molybdenum on a re-entrant glass stem 14. A bridge 13 spaces the wires 9, 10, 11. Within the copper section 1 is a tungsten &c. anti-cathode 15 cooled from the back by water, air, &c. Opposite the anti-cathode is a side-tube 18 closed by a window of thin metal, glass, &c. The envelope is exhausted so highly that current is independent of positive ionization. Traces of oxide are removed by introducing hydrogen, heating externally, and re-exhausting In another form, the cathode rays strike a thin platinum, silver, or like window in the end of the metal section, the X-rays then passing through this window and through a cooling-jacket, which has an outer window of thin aluminium &c. If the inner window is very thin, the cathode rays may pass through it; in this case, the outer window is very thin, or the cooling-jacket may be omitted.