Monocoque structure and large electrode beaded rob re-entrant seals for

Abstract

A pulsed high energy arc-tube flashlamp comprises a quartz flashlamp envelope that is about 2000 mm long and has an outside diameter of approximately forty-eight mm. Each end necks down to an outside diameter of about thirty-eight mm to accommodate an anode re-entrant seal assembly at one end and a cathode re-entrant seal assembly at the other end. Each anode and cathode comprises a beaded electrode rod of tungsten with an unusually large 0.25 inch diameter. A reflective metal paint or white oxide paint is added to the end necks to improve the lamp starting characteristics and to protect the cassette mounting o-ring and lamp cable junction box from radiation. A TEFLON shrink sleeve is shrunk over each outside end of the flashlamp envelope and such provides a small amount of cushion for the lamp mounts in the laser cassette. The monocoque body structure does not need separate lamp mounting bases, and thus overall provides a mechanically simpler and superior structure that is far more reliable. The prior art demonstrates that necking down glass envelopes of lamps is common practice, but here such necking down is limited to that diameter which just suits the external mounting base requirements. The re-entrant seal cup area provides a large volume reservoir for filling with RTV, which bonds the lead wire insulation to the quartz and provide cable support and additional electrical insulation to provide zero lamp insulation failure.