Willi Bette

Excimer Lasers With Large Discharge Cross Section

The operating characteristics of a pulse forming network (PFN) for large volume excimer lasers comprising paralleled waterline capacitors are described. The PFN uses different kinds of switches such as thyratrons and a multichannel pseudo spark switch. The X-ray pre-ionizer is composed of a low ohmic pulse generator and an X-ray tube with a hollow cathode. To investigate the evolution and damping of gas inhomogenities, caused by the short laser discharge, optical interferometry with high time resolution is used. Results and conditions are presented for operating the excimer laser at different wavelengths with high energy output.

Fast Pulse Transformers In Laser Pulse Power Circuits

A new concept for fast pulse transformers is described. The transformers have been used in two applications with excimer lasers: a) To produce a short 100 MW/90 kV/100 ns pulse for driving a preionization X-ray source. b) To step up the voltage in a command charging circuit for charging a water pulse forming network within a few microseconds to an energy level of 100 Joule electrical energy per pulse. A report is given on the performance characteristics at repetition rates up to 100 Hz. A coupling factor close to unity and nearly ideal transformer efficiencies have been achieved.