Influence of preionization on irradiation characteristics of pulsed xenon lamp

Summary form only given. High power xenon flashlamps are mainly used in laser inertial confinement fusion facility as the optical pump source. The preionization technique was used to fire the xenon flashlamps and to improve the radiant efficiency and gain of amplifier. It is difficult to find papers describing characteristics and mechanism of preionization. This work is devoted to study the characteristics of preionization and its mechanism during main discharge of high power xenon flashlamps. In experiments, electrical parameters of discharge are recorded by high voltage probe and rogowski coils. The radiation energy of flashlamps was obtained by a pyroelectric energy meter. The plasma channel profiles were captured by a high speed CCD camera. In addition, the spectral distribution in a flash was acquired by a spectrometer with CCD as detector. With proper time interval between preionization and main discharge, the radiant efficiency of flashlamps will increase by 3.8%~5.1%. While the interval is less than period of prepulse, the main capacitor will discharge the preionization circuit and the current through it oscillates badly. Meantime the radiant efficiency will decrease by more than 10%. Spectroscopy results indicate that the preionization pulse will improve the spectral distribution of flashlamp during main discharge. With preionization discharge, the blue shift of spectral distribution curve will be reduced, and it can improve the gain of amplifier.