A fast and portable mega-volt source for pulsed power applications

Abstract

Summary form only given. Fast and portable pulse power systems especially in the megavolt range have always been in demand for years. Use of such fast rise time, high voltage generators are considered to be of great interest for variety of application like - driving portable X-ray sources and special free electron lasers. Their use with pulse forming lines results in the production of relatively compact particle beam accelerators. They have also been found useful in driving wide band electromagnetic radiators. In reference to above mentioned applications a battery powered and portable, nanosecond rise time megavolt system has been developed. In this system, 60 Watt SMPS DC to DC converter has been used for charging 0.24 /spl mu/F capacitor, which acts as a primary source of energy. The SMPS is driven by two normal 12 V Panasonic batteries and gives an output of 30 KV @ 2 mA. The capacitor is made to discharge into the primary of 'pulse transformer' through spark gap switch. It is an air-core transformer with the coupling coefficient of 0.66 which can produce maximum output voltage up to 1.5 MV. In the coaxial geometry, it has single turn primary to achieve fast rise time and multi-turn secondary. For attaining high reliability and repeatability, trade off has been made between good coupling coefficient and high voltage stand off while designing. Low leakage inductance and low distributed capacitance is also required in order to obtain fast rise time hence due considerations have been made in the design to fulfill the same. After making trade off among these parameters carefully, a pulse transformer with rise time of less than 10 ns has been designed and built. In the presented paper attempt has also been made to create the methodology of designing pulse transformers delivering high power impulses with faster rise times on secondary side.