Design and Improvement of Wate-Dielectric Helix Long Pulse Forming Line

Summary form only given. Based on a water-dielectric helix line, a 2.2 m long accelerator with a diameter of 0.4 m was designed and tested. The influence of the impedance mismatching between the joint section in pulse forming line and the helical line on the voltage waveform of the diode was analyzed. A high impedance annulus made of macromolecule material with an inner radius of 10cm and an outer radius of 18cm was added to the joint section. By making the impedance of the joint section be close to mat of the helical line and the electric length minimize, the upshot was eliminated, the fall time was minimized, and a square pulse with a rise time about 18 ns, a fall time about 40ns and a pulse top duration about 200 ns was obtained.