High Voltage Capillary Discharge System for Excitation of Soft X-ray Laser

Abstract

Summary form only given. Characteristics of high voltage capillary discharge system for the excitation of capillary discharge soft X-ray laser, which has a high step-up ratio of discharge voltage to the charging voltage of primary capacitors, will be reported. The discharge system consists of a 2.2 muF LC inversion generator, a 2:54 step-up transformer, a 3 nF water capacitor, a self triggered gap switch and a load capillary. The LC generator and the pulse transformer are connected through a low stray inductance transmission line of about 400 nH. In addition, the chamber, in which the step-up transformer is set, is filled with 2 atm SF6 gas to increase dielectric strength. Consequently, leakage inductance of pulse transformer is decreased to about 300 nH. The low inductance, which exists between the primary LC generator and the secondary water capacitor, enables the water capacitor to be charged within 2.5 mus without saturation of the core of pulse transformer or much energy loss through the water. With this new system, the obtained step-up ratio of the water capacitor voltage to the initial charging voltage of a capacitor used in the LC generator is about 35. Therefore, when the charging voltage of primary capacitor is 20 kV, the charging voltage of 3 nF water capacitor reaches 700 kV. With this high voltage capillary discharge system, discharge current can be increased to generate high-density and high-temperature long plasma column in order to shorten the wavelength of the laser to EUV range.