A rep-rated pulser for generating fast-rising pulsed magnetic fields

摘要

A pulser is described which drives an inductor assembly for generating a fast-rising pulsed magnetic field. It is capable of generating a 1 kG field in a 1 L volume with a 1 mu s risetime, a 20 mu s falltime, and a pulse width up to 50 mu s. The repetition rate is single shot to 4 kHz. Energy recovery is utilized to reduce power supply requirements. A thyratron high-voltage circuit provides the required fast risetime, and high-power semiconductors are used in an active crowbar circuit to form the proper pulse shape and to perform energy recovery. At 4 kHz, burst length can be up to 5 s, with correspondingly longer bursts at lower repetition rates. The presence of fast high-voltage transitions required careful attention to dI/dt sharing in the lower-voltage semiconductor circuits. A control unit provides all timing signals for operation of the pulser, and sets repetition rate and burst length. An upgraded version has been designed and extensively simulated which operates at up to 7 kHz with a field volume of 5 L.