GB1468137A - High intensity radiation source - Google Patents

Abstract

1468137 Discharge lamp CANADIAN PATENTS & DEVELOPMENT Ltd 12 June 1975 [13 June 1974] 25247/75 Heading H1D [Also in Division H2] A high intensity stabilized long arc source of radiation (U.V., visible, I.R.) comprises a cylindrical arc tube transparent at least in part, with two electrodes on the axis, means for injecting cooling liquid to form a wall inside the tube, and provision for inert gas injection: a starting circuit initiates an arc between the electrodes stabilized by the gas and constricted by the liquid, with positive dynamic impedance. The liquid, e.g. water, is forced helically along quartz tube 22 from annular chamber 39 in the constrictor block attached to but insulated from anode 24 to exit at 33 in the cathode block 23, to be cooled and recirculated; anode and cathode copper blocks 24, 23 also have internal liquid cooling by passages 37, 38, 27, 28. Rare gas at a pressure above atmosphere may be injected at either end helically in the same rotational sense; in the Fig. the linear gas flow is opposite to the liquid, entering annular chamber 31 from supply 30 and leaving through duct 44 for recirculation. The D.C. arc is struck by a high voltage surge between thoriated W cathode 26 and similar anode surface 49, and is maintained temporarily by a capacitor chain until the current from the supply can be built up (Figs. 3-6, not shown). Between thoriated W-lined constriction 47 and the anode surface 49 the arc is not stabilized by gas and is forced to wander annularly by magnet 48. In an A.C. or D.C. arc both electrodes may be so equipped. In a second embodiment (Fig. 7, not shown), gas and liquid flow in the same direction, both being collected from an expansion chamber round the anode, which now has no separate constriction in front of it.